U.S. Environmental Protection Agency 

Documentation of OMB Review Under Executive Order 12866 

Title of Action: tate Implementation Plans: 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 

Docket#: EPA-HQ-OAR-2012-0322 I FRL#: 19924-05-0AR I RIN: §oso-AR68 

This action was submitted to the Office of Management and Budget (OMB) for review under Executive Order (E.O.) 

12866, titled Regulatory Planning and Review (58 FR 51735, October 4, 1993). Whenever EPA makes publicly available 

a regulatory action that was reviewed under E.O. 12866, section 6(a)(3)(E) of the E.O. directs the Agency to also: 

(1) Make available to the public a copy of the information that was provided to OMS's Office of Information and 

Regulatory Affairs (OIRA) for review under the E.O., i.e., the text of the draft regulatory action and, if applicable, 

an assessment of the potential costs and benefits, as well as additional information for those actions that are 

determined to be economically significant under the E.O. (Information requirements are described in sections 

6(a)(3)(B) and (C)). 

(2) Identify for the public any substantive changes between the draft submitted to OIRA and the action that was 

subsequently issued, using a method that is complete, clear, and simple. 

(3) Identify for the public those substantive changes made at the suggestion or recommendation of OIRA. 

For this regulatory action, were substantive changes made to information reviewed under E.O. 

12866? [Please check the appropriate answer.] 

Cl No. (In the docket, include the information identified in item (1) below.] 

lEI Yes. [In the docket, include the information identified in items (1) - (3) below.] 

Accordingly, the Agency has included this form and the following information in the public 

docket for this regulatory action: [Please check the appropriate information.] 

lEI (1) A copy of the information that was provided to OIRA for review under the E.O. 

lEI (2) Documentation of any substantive changes made to the draft regulatory text that was 

submitted to OIRA when compared with what was subsequently made publicly available. 

The documentation is provided on the pages following this form. Changes made at the 

suggestion or recommendation of OIRA, if any, are clearly identified through attribution to 

OIRA. EPA has used one or more of the following methods to note changes: (Select the 

appropriate option(s).] 

lEI (a) Red line-Strikeout- A copy of the draft regulatory action submitted, using redlinestrikeout to show the substantive changes that were made. 

[J (b) Hand Markup- A copy of the draft regulatory action submitted, using handwritten notes 

to show the substantive changes that were made. 

[J (c) Note to the file- A document that identifies the substantive changes that were made, 

with page and paragraph references to the draft regulatory action that was submitted. 

If you have any questions about this regulatory action or this documentation, please call the 

contact: 

Name: r-~isa tt -------------,1 Email: utton.lisa®epa.gov I Phone: (919) 541-3450 

Rev1sed 05/05/2010 
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6560-50-P 

ENVIRONMENTAL PROTECTION AGENCY 

40 CFR Part 52 

[EPA-HQ-OAR-2012-0322; FRL-9924-05-OAR] 

RIN 2060-AR68 

State Implementation Plans: 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 

AGENCY: Environmental Protection Agency (EPA). 

ACTION: Final rule. 

SUMMARY: The Environmental Protection Agency (EPA) is taking final action on a petition 

for rulemaking filed by the Sierra Club (Petitioner) that concerns how provisions in EPAapproved state implementation plans (SIPs) treat excess emissions during periods of startup, 

shutdown or malfunction (SSM). Further, the EPA is clarifying, restating and revising its 

guidance concerning its interpretation of the Clean Air Act (CAA or Act) requirements with 

respect to treatment of excess emissions that occur during periods of SSM. The EPA evaluated 

existing SIP provisions in a number of states for consistency with the EPA’s interpretation of the 

CAA and in light of recent court decisions addressing this issue. The EPA is issuing a finding 

that certain SIP provisions in 37 states (applicable in 46 statewide and local jurisdictions) are 

substantially inadequate to meet CAA requirements and thus is issuing a “SIP call” for each of 

those 37 states. Further, the EPA is establishing a due date for states subject to this SIP call 

action to submit corrective SIP revisions. Finally, this final action embodies the EPA’s updated 

SSM Policy as it applies to SIP provisions. The SSM Policy provides guidance to states for 
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compliance with CAA requirements for SIP provisions applicable to excess emissions during 

SSM events. 

DATES: The effective date of this final action is [INSERT DATE 30 DAYS AFTER 

PUBLICATION IN THE FEDERAL REGISTER]. The deadline for each affected state to 

submit its corrective SIP revision is November 22, 2016. 

ADDRESSES: The EPA has established a docket for this rulemaking under Docket ID No. 

EPA-HQ-OAR-2012-0322. All documents in the docket are listed in the 

http://www.regulations.gov index. Although listed in the index, some information is not publicly 

available, e.g., Confidential Business Information or other information whose disclosure is 

restricted by statute. Certain other material, such as copyrighted material, will be publicly 

available only in hard copy. Publicly available docket materials are available either electronically 

at http://www.regulations.gov or in hard copy at the U.S. Environmental Protection Agency, 

EPA Docket Center, William Jefferson Clinton West Building, Room 3334, 1301 Constitution 

Ave., NW, Washington, D.C. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., 

Monday through Friday, excluding legal holidays. The telephone number for the Public Reading 

Room is (202) 566-1744, and the telephone number for the Office of Air and Radiation Docket is 

(202) 566-1742. 

FOR FURTHER INFORMATION CONTACT: Ms. Lisa Sutton, U.S. EPA, Office of Air 

Quality Planning and Standards, State and Local Programs Group (C539-01), Research Triangle 

Park, NC 27711, telephone number (919) 541-3450, email address: sutton.lisa@epa.gov. 

SUPPLEMENTARY INFORMATION: 

For information related to a specific SIP, please contact the appropriate EPA Regional 

Office: 
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EPA 

Regional 

Office 

Contact for Regional Office (person, 

mailing address, telephone number) State 

I Alison Simcox, Environmental 

Scientist, EPA Region 1, 5 Post Office 

Square, Suite 100, Boston, MA 02109-

3912, (617) 918-1684. 

Connecticut, Massachusetts, 

Maine, New Hampshire, 

Rhode Island and Vermont. 

II Paul Truchan, EPA Region 2, 290 

Broadway, 25th Floor, New York, NY 

10007-1866, (212) 637-3711. 

New Jersey, New York, Puerto 

Rico and Virgin Islands. 

III Amy Johansen, EPA Region 3, 1650 

Arch Street, Philadelphia, PA 19103-

2029, (215) 814-2156. 

District of Columbia, 

Delaware, Maryland, 

Pennsylvania, Virginia and 

West Virginia. 

IV Joel Huey, EPA Region 4, Atlanta 

Federal Center, 61 Forsyth Street, SW, 

Atlanta, GA 30303-8960, (404) 562-

9104. 

Alabama, Florida, Georgia, 

Kentucky, Mississippi, North 

Carolina, South Carolina and 

Tennessee. 

V Christos Panos, Air and Radiation 

Division (AR-18J), EPA Region 5, 77 

West Jackson Boulevard, Chicago, IL 

60604-3507, (312) 353-8328. 

Illinois, Indiana, Michigan, 

Minnesota, Ohio and 

Wisconsin. 

VI Alan Shar (6PD-L), EPA Region 6, 

Fountain Place 12th Floor, Suite 1200, 

1445 Ross Avenue, Dallas, TX 75202-

2733, (214) 665-6691. 

Arkansas, Louisiana, New 

Mexico, Oklahoma and Texas. 

VII Lachala Kemp, EPA Region 7, Air 

Planning and Development Branch, 

11201 Renner Boulevard, Lenexa, KS 

66219-9601, (913) 551-7214. Alternate 

contact is Ward Burns, (913) 551-7960. 

Iowa, Kansas, Missouri and 

Nebraska. 

VIII Adam Clark, Air Quality Planning Unit 

(8P-AR) Air Program, Office of 

Partnership and Regulatory Assistance, 

EPA Region 8, 1595 Wynkoop Street, 

Denver, CO 80202-1129, (303) 312-

7104. 

Colorado, Montana, North 

Dakota, South Dakota, Utah 

and Wyoming. 

IX Lisa Tharp, EPA Region 9, Air 

Division, 75 Hawthorne Street (AIR-8), 

San Francisco, CA 94105-3920, (415) 

947-4142. 

Arizona, California, Hawaii, 

Nevada and the Pacific 

Islands. 
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EPA 

Regional 

Office 

Contact for Regional Office (person, 

mailing address, telephone number) State 

X Donna Deneen, Environmental 

Engineer, Office of Air, Waste and 

Toxics (AWT-107), EPA Region 10, 

1200 Sixth Avenue, Suite 900, Seattle, 

WA 98101-3140, (206) 553-6706. 

Alaska, Idaho, Oregon, and 

Washington. 

 

I. General Information 

A. Does this action apply to me? 

Entities potentially affected by this rule include states, U.S. territories, local authorities 

and eligible tribes that are currently administering, or may in the future administer, EPAapproved implementation plans (“air agencies”).1

 The EPA’s action on the petition for 

rulemaking filed by the Sierra Club with the EPA Administrator on June 30, 2011 (the Petition), 

is potentially of interest to all such entities because the EPA is addressing issues related to basic 

CAA requirements for SIPs. Through this rulemaking, the EPA is both clarifying and applying 

its interpretation of the CAA with respect to SIP provisions applicable to excess emissions 

during SSM events in general. In addition, the EPA is issuing findings that some of the specific 

SIP provisions in some of the states identified in the Petition and some SIP provisions in 

 

1

 The EPA respects the unique relationship between the U.S. government and tribal authorities 

and acknowledges that tribal concerns are not interchangeable with state concerns. Under the 

CAA and EPA regulations, a tribe may, but is not required to, apply for eligibility to have a tribal 

implementation plan (TIP). For convenience, the EPA refers to “air agencies” in this rulemaking 

collectively when meaning to refer in general to states, the District of Columbia, U.S. territories, 

local air permitting authorities and eligible tribes that are currently administering, or may in the 

future administer, EPA-approved implementation plans. This final action does not include action 

on any provisions in any TIP. The EPA therefore refers to “state” or “states” rather than “air 

agency” or “air agencies” when meaning to refer to one, some, or all of the states at issue in this 

rulemaking. The EPA also uses “state” or “states” rather than “air agency” or “air agencies” 

when quoting or paraphrasing the CAA or other document that uses that term even when the 

original referenced passage may have applicability to tribes as well. 
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additional states are substantially inadequate to meet CAA requirements, pursuant to CAA 

section 110(k)(5), and thus those states (named in section II.C of this document) are directly 

affected by this rulemaking. For example, where a state’s existing SIP includes an affirmative 

defense provision that would purport to alter the jurisdiction of the federal courts to assess 

monetary penalties for violations of CAA requirements, then the EPA is determining that the SIP 

provision is substantially inadequate because the provision is inconsistent with fundamental 

requirements of the CAA. This rule may also be of interest to the public and to owners and 

operators of industrial facilities that are subject to emission limitations in SIPs, because it will 

require changes to certain state rules applicable to excess emissions during SSM events. This 

action embodies the EPA’s updated SSM Policy concerning CAA requirements for SIP 

provisions relevant to excess emissions during SSM events. 

B. Where can I get a copy of this document and other related information? 

In addition to being available in the docket, an electronic copy of this notice will also be 

available on the World Wide Web. Following signature by the EPA Administrator, a copy of this 

notice will be posted on the EPA’s website, under “State Implementation Plans to Address 

Emissions During Startup, Shutdown and Malfunction,” at 

http://www.epa.gov/air/urbanair/sipstatus. The EPA’s initial proposed response to the Petition in 

the February 2013 proposal, the EPA’s revised proposed response to the Petition in the 

September 2014 supplemental notice of proposed rulemaking (SNPR) and the EPA’s response to 

significant adverse comments on these documents may be found in the docket for this action. 

C. How is the preamble organized? 

The information presented in this preamble is organized as follows: 

 I. General Information
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A. Does this action apply to me?

B. Where can I get a copy of this document and other related information?

C. How is the preamble organized?

D. What is the meaning of key terms used in this document?

II. Overview of Final Rule and Its Consequences

A. Summary

B. What the Petitioner Requested 

C. To which air agencies does this rulemaking apply and why?

D. What are the next steps for states that are receiving a finding of substantial 

inadequacy and a SIP call?

E. What are potential impacts on affected states and sources?

F. What happens if an affected state fails to meet the SIP submission 

deadline?

G. What is the status of SIP provisions affected by this SIP call action in the 

interim period starting when the EPA promulgates the final SIP call and 

ending when the EPA approves the required SIP revision?

III. Statutory, Regulatory and Policy Background

IV. Final Action in Response to Request to Rescind the EPA Policy Interpreting the 

CAA to Allow Affirmative Defense Provisions

A. What the Petitioner Requested

B. What the EPA Proposed

C. What Is Being Finalized in This Action

D. Response to Comments Concerning Affirmative Defense Provisions in 

SIPs

V. Generally Applicable Aspects of the Final Action in Response to Request for the 

EPA’s Review of Specific Existing SIP Provisions for Consistency with CAA 

Requirements

A. What the Petitioner Requested

B. What the EPA Proposed

C. What Is Being Finalized In This Action

D. Response to Comments Concerning the CAA Requirements for SIP 

Provisions Applicable to SSM Events 

VI. Final Action in Response to Request that the EPA Limit SIP Approval to the Text 

of State Regulations and Not Rely upon Additional Interpretive Letters from the 

State

A. What the Petitioner Requested

B. What the EPA Proposed

C. What Is Being Finalized In This Action

D. Response to Comments Concerning Reliance on Interpretive Letters in 

SIP Revisions

VII. Clarifications, Reiterations and Revisions to the EPA’s SSM Policy

A. Applicability of Emission Limitations During Periods of SSM

1. What the EPA Proposed

2. What is Being Finalized in This Action

3. Response to Comments
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B. Alternative Emission Limitations During Periods of Startup and Shutdown

1. What the EPA Proposed

2. What is Being Finalized in This Action

3. Response to Comments

C. Director’s Discretion Provisions Pertaining to SSM Events

1. What the EPA Proposed

2. What is Being Finalized in This Action

3. Response to Comments

D. Enforcement Discretion Provisions Pertaining to SSM Events

1. What the EPA Proposed

2. What is Being Finalized in This Action

3. Response to Comments

E. Affirmative Defense Provisions in SIPs During Any Period of Operation

F. Relationship Between SIP Provisions and Title V Regulations

G. Intended Effect of the EPA’s Action on the Petition

VIII. Legal Authority, Process and Timing for SIP Calls

A. SIP Call Authority Under Section 110(k)(5)

1. General Statutory Authority

2. Substantial Inadequacy of Automatic Exemptions

3. Substantial Inadequacy of Director’s Discretion Exemptions

4. Substantial Inadequacy of Improper Enforcement Discretion 

Provisions

5. Substantial Inadequacy of Affirmative Defense Provisions

B. SIP Call Process Under Section 110(k)(5)

C. SIP Call Timing Under Section 110(k)(5)

D. Response to Comments Concerning SIP Call Authority, Process and 

Timing

IX. What is the EPA’s final action for each of the specific SIP provisions identified in 

the Petition or by the EPA?

A. Overview of the EPA’s Evaluation of Specific SIP Provisions

B. Affected States in EPA Region I

C. Affected State in EPA Region II

D. Affected States in EPA Region III

E. Affected States and Local Jurisdictions in EPA Region IV

F. Affected States in EPA Region V

G. Affected States in EPA Region VI

H. Affected States in EPA Region VII

I. Affected States in EPA Region VIII

J. Affected States and Local Jurisdictions in EPA Region IX

K. Affected States in EPA Region X

X. Implementation Aspects of EPA’s SSM SIP Policy

A. Recommendations Concerning Alternative Emission Limitations for 

Startup and Shutdown

B. Recommendations for Compliance With Section 110(l) and Section 193 

for SIP Revisions
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XI. Statement of the EPA’s SSM SIP Policy as of 2015

A. Definitions

B. Emission limitations in SIPs must apply continuously during all modes of 

operation, without automatic or discretionary exemptions or overly broad 

enforcement discretion provisions that would bar enforcement by the EPA 

or by other parties in federal court through a citizen suit.

C. Emission limitations in SIPs may contain components applicable to 

different modes of operation that take different forms, and numerical 

emission limitations may have differing levels and forms for different 

modes of operation.

D. Recommendations for Development of Alternative Emission Limitations 

Applicable During Startup and Shutdown

E. Enforcement Discretion Provisions

F. Affirmative Defense Provisions in SIPs

G. Anti-Backsliding Considerations

XII. Environmental Justice Consideration

XIII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 

Order 13563: Improving Regulation and Regulatory Review

B. Paperwork Reduction Act (PRA)

C. Regulatory Flexibility Act (RFA)

D. Unfunded Mandates Reform Act (UMRA)

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with Indian Tribal 

Governments

G. Executive Order 13045: Protection of Children from Environmental 

Health Risks and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution or Use

I. National Technology Transfer and Advancement Act (NTTAA)

J. Executive Order 12898: Federal Actions to Address Environmental Justice 

in Minority Populations and Low-Income Populations

K. Determination Under Section 307(d)

L. Congressional Review Act (CRA)

XIV. Judicial Review

XV. Statutory Authority 

D. What is the meaning of key terms used in this document? 

For the purpose of this notice, the following definitions apply unless the context indicates 

otherwise: 

The terms Act or CAA or the statute mean or refer to the Clean Air Act. 
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The term affirmative defense means, in the context of an enforcement proceeding, a 

response or defense put forward by a defendant, regarding which the defendant has the burden of 

proof, and the merits of which are independently and objectively evaluated in a judicial or 

administrative proceeding. The term affirmative defense provision means more specifically a 

state law provision in a SIP that specifies particular criteria or preconditions that, if met, would 

purport to preclude a court from imposing monetary penalties or other forms of relief for 

violations of SIP requirements in accordance with CAA section 113 or CAA section 304. 

The term Agency means or refers to the EPA. When not capitalized, this term refers to an 

agency in general and not specifically to the EPA. 

The terms air agency and air agencies mean or refer to states, the District of Columbia, 

U.S. territories, local air permitting authorities with delegated authority from the state and tribal 

authorities with appropriate CAA jurisdiction. 

The term alternative emission limitation means, in this notice, an emission limitation in a 

SIP that applies to a source during some but not all periods of normal operation (e.g., applies 

only during a specifically defined mode of operation such as startup or shutdown). An alternative 

emission limitation is a component of a continuously applicable SIP emission limitation, and it 

may take the form of a control measure such as a design, equipment, work practice or operational 

standard (whether or not numerical). This definition of the term is independent of the statutory 

definitions in sections 111(h)(3) and 112(h)(3). The latter definitions pertain to the conditions 

under which the EPA may pursuant to sections 111 and 112 promulgate emission limitations, or 

components of emission limitations, that are not necessarily in numeric format. 
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The term automatic exemption means a generally applicable provision in a SIP that 

would provide that if certain conditions existed during a period of excess emissions, then those 

exceedances would not be considered violations of the applicable emission limitations. 

The term director’s discretion provision means, in general, a regulatory provision that 

authorizes a state regulatory official unilaterally to grant exemptions or variances from otherwise 

applicable emission limitations or control measures, or to excuse noncompliance with otherwise 

applicable emission limitations or control measures, which would be binding on the EPA and the 

public. 

The term EPA refers to the United States Environmental Protection Agency. 

The term emission limitation means, in the context of a SIP, a legally binding restriction 

on emissions from a source or source category, such as a numerical emission limitation, a 

numerical emission limitation with higher or lower levels applicable during specific modes of 

source operation, a specific technological control measure requirement, a work practice standard, 

or a combination of these things as components of a comprehensive and continuous emission 

limitation in a SIP provision. In this respect, the term emission limitation is defined as in section 

302(k) of the CAA. By definition, an emission limitation can take various forms or a 

combination of forms, but in order to be permissible in a SIP it must be applicable to the source 

continuously, i.e., cannot include periods during which emissions from the source are legally or 

functionally exempt from regulation. Regardless of its form, a fully approvable SIP emission 

limitation must also meet all substantive requirements of the CAA applicable to such a SIP 

provision, e.g., the statutory requirement of section 172(c)(1) for imposition of reasonably 

available control measures and reasonably available control technology (RACM and RACT) on 

sources located in designated nonattainment areas. 
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The term excess emissions means the emissions of air pollutants from a source that 

exceed any applicable SIP emission limitation. In particular, this term includes those emissions 

above the otherwise applicable SIP emission limitation that occur during startup, shutdown, 

malfunction or other modes of source operation, i.e., emissions that would be considered 

violations of the applicable emission limitation but for an impermissible automatic or 

discretionary exemption from such emission limitation. 

The term February 2013 proposal means the notice of proposed rulemaking that the EPA 

signed on February 12, 2013, and published in the Federal Register on February 22, 2013. The 

February 2013 proposal comprises the EPA’s initial proposed response to the Petition. The EPA 

subsequently issued the September 2014 SNPR that updated and revised the EPA’s February 

2013 proposal with respect to affirmative defense provisions in SIPs. 

The term malfunction means a sudden and unavoidable breakdown of process or control 

equipment. 

The term NAAQS means national ambient air quality standard or standards. These are the 

national primary and secondary ambient air quality standards that the EPA establishes under 

CAA section 109 for criteria pollutants for purposes of protecting public health and welfare. 

The term Petition refers to the petition for rulemaking titled, “Petition to Find Inadequate 

and Correct Several State Implementation Plans under Section 110 of the Clean Air Act Due to 

Startup, Shutdown, Malfunction, and/or Maintenance Provisions,” filed by the Sierra Club with 

the EPA Administrator on June 30, 2011. 

The term Petitioner refers to the Sierra Club. 

The term practically enforceable means, in the context of a SIP emission limitation, that 

the limitation is enforceable as a practical matter (e.g., contains appropriate averaging times, 
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compliance verification procedures and recordkeeping requirements). The term uses 

“practically” as it means “in a practical manner” and not as it means “almost” or “nearly.” In this 

notice, the EPA uses the term “practically enforceable” as interchangeable with the term 

“practicably enforceable.” 

The term shutdown means, generally, the cessation of operation of a source for any 

reason. In this notice, the EPA uses this term in the generic sense. In individual SIP provisions it 

may be appropriate to include a specifically tailored definition of this term to address a particular 

source category for a particular purpose. 

The term SIP means or refers to a State Implementation Plan. Generally, the SIP is the 

collection of state statutes and regulations approved by the EPA pursuant to CAA section 110 

that together provide for implementation, maintenance and enforcement of a national ambient air 

quality standard (or any revision thereof) promulgated under section 109 for any air pollutant in 

each air quality control region (or portion thereof) within a state. In some parts of this notice, 

statements about SIPs in general would also apply to tribal implementation plans in general even 

though not explicitly noted. 

The term SNPR means the supplemental notice of proposed rulemaking that the EPA 

signed and posted on the Agency website on September 5, 2014, and published in the Federal 

Register on September 17, 2014. Supplementing the February 2013 proposal, the SNPR 

comprises the EPA’s revised proposed response to the Petition with respect to affirmative 

defense provisions in SIPs. 

The term SSM refers to startup, shutdown or malfunction at a source. It does not include 

periods of maintenance at such a source. An SSM event is a period of startup, shutdown or 
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malfunction during which there are exceedances of the applicable emission limitations and thus 

excess emissions. 

The term SSM Policy refers to the cumulative guidance that the EPA has issued as of any 

given date concerning its interpretation of CAA requirements with respect to treatment of excess 

emissions during periods of startup, shutdown and malfunction at a source in SIP provisions. The 

most comprehensive statement of the EPA’s SSM Policy prior to this final action is embodied in 

a 1999 guidance document discussed in more detail in this final action. That specific guidance 

document is referred to as the 1999 SSM Guidance. The final action described in this notice 

embodies the EPA’s updated SSM Policy for SIP provisions relevant to excess emissions during 

SSM events. In section XI of this notice, the EPA provides a statement of the Agency’s SSM SIP 

Policy as of 2015. 

The term startup means, generally, the setting in operation of a source for any reason. In 

this notice, the EPA uses this term in the generic sense. In an individual SIP provision it may be 

appropriate to include a specifically tailored definition of this term to address a particular source 

category for a particular purpose. 

II. Overview of Final Rule and Its Consequences 

A. Summary 

The EPA is in this notice taking final action on a petition for rulemaking that the Sierra 

Club filed with the EPA Administrator on June 30, 2011. The Petition concerns how air agency 

rules in EPA-approved SIPs treat excess emissions during periods of SSM of industrial process 

or emission control equipment. Many of these rules were added to SIPs and approved by the 

EPA in the years shortly after the 1970 amendments to the CAA, which for the first time 

provided for the system of clean air plans that were to be prepared by air agencies and approved 
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by the EPA. At that time, it was widely believed that emission limitations set at levels 

representing good control of emissions during periods of so-called “normal” operation (which, 

until no later than 1982, was meant by the EPA to refer to periods of operation other than during 

startup, shutdown, maintenance or malfunction) could in some cases not be met with the same 

emission control strategies during periods of startup, shutdown, maintenance or malfunction.2

Accordingly, it was common for state plans to include provisions for special, more lenient 

treatment of excess emissions during such periods of startup, shutdown, maintenance or 

malfunction. Many of these provisions took the form of absolute or conditional statements that 

excess emissions from a source, when they occur during startup, shutdown, malfunction or 

otherwise outside of the source’s so-called “normal” operations, were not to be considered 

violations of the air agency rules; i.e., these emissions were considered exempt from legal 

control. 

Excess emission provisions for startup, shutdown, maintenance and malfunctions were 

often included as part of the original SIPs that the EPA approved in 1971 and 1972. In the early 

1970s, because the EPA was inundated with proposed SIPs and had limited experience in 

processing them, not enough attention was given to the adequacy, enforceability and consistency 

of these provisions. Consequently, many SIPs were approved with broad and loosely defined 

provisions to control excess emissions. Starting in 1977, however, the EPA discerned and 

 

2

 Since at least 1982, however, the EPA has used the term “normal” in the SSM Policy in the 

ordinary sense of the word to distinguish between predictable modes of source operation such as 

startup and shutdown and genuine “malfunctions,” which are by definition supposed to be 

unpredictable and unforeseen events and which could not have been precluded by proper source 

design, maintenance and operation. See, e.g., 1982 SIP Guidance, Attachment at 2, in which the 

EPA states, “[s]tart-up and shutdown of process equipment are part of the normal operation of a 

source and should be accounted for in the design and implementation of the operating procedure 

for the process and control equipment.” 
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articulated to air agencies that exemptions for excess emissions during such periods were 

inconsistent with certain requirements of the CAA. The EPA also realized that such provisions 

allow opportunities for sources to emit pollutants during such periods repeatedly and in 

quantities that could cause unacceptable air pollution in nearby communities with no legal 

pathway within the existing EPA-approved SIP for air agencies, the EPA, the public or the courts 

to require the sources to make reasonable efforts to reduce these emissions. The EPA has been 

more careful after 1977 not to give new approval to SIP provisions that are inconsistent with the 

CAA and has issued several guidance memoranda to advise states on how to avoid impermissible 

provisions3 as they expand and revise their SIPs. The EPA has also found several SIPs to be 

deficient because of problematic SSM provisions and called upon the affected states to amend 

their SIPs. However, in light of the other high-priority work facing both air agencies and the 

EPA, the EPA had not until the February 2013 proposal initiated a broader effort to require a 

larger number of states to remove impermissible provisions from their SIPs and to adopt other, 

approvable approaches for addressing excess emissions when appropriate. Public interest groups, 

including the Petitioner, have sued the EPA in several state-specific cases concerning SIP issues, 

and they have been urging the EPA to give greater priority generally to addressing the issue of 

 

3

 The term “impermissible provision” as used throughout this notice is generally intended to refer 

to a SIP provision that the EPA now believes to be inconsistent with requirements of the CAA. 

As described later in this notice (see section VIII.A), the EPA is proposing to find a SIP 

“substantially inadequate” to meet CAA requirements where the EPA determines that the SIP 

includes an impermissible provision. 
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SSM provisions in SIPs. In one of these SIP cases, the EPA entered into a settlement agreement 

requiring it to respond to the Petition from the Sierra Club. A copy of the settlement agreement is 

provided in the docket for this rulemaking.4 

The EPA emphasizes that there are other approaches that would be consistent with CAA 

requirements for SIP provisions that states can use to address emissions during SSM events. 

While automatic exemptions and director’s discretion exemptions from otherwise applicable 

emission limitations are not consistent with the CAA, SIPs may include criteria and procedures 

for the use of enforcement discretion by air agency personnel. Similarly, SIPs may, rather than 

exempt emissions during SSM events, include emission limitations that subject those emissions 

to alternative numerical limitations or other technological control requirements or work practice 

requirements during startup and shutdown events, so long as those components of the emission 

limitations meet applicable CAA requirements. In this action, the EPA is again articulating its 

interpretation of the statute in the SSM Policy that reflects these principles and is applying this 

interpretation to issue a SIP call for specific existing provisions in the SIPs of 37 states. In some 

cases, the EPA’s review involved a close reading of the provision in the SIP and its context to 

discern whether it was in fact an exemption, a statement regarding exercise of enforcement 

discretion by the air agency or an affirmative defense. Each state will ultimately decide how to 

address the SIP inadequacies identified by the EPA in this final action. The EPA acknowledges 

that for some states, this rulemaking entailed the EPA’s evaluation of SIP provisions that may 

 

4 See Settlement Agreement executed November 30, 2011, in the rulemaking docket at EPA-HQOAR-2012-0322-0039, to address a lawsuit filed by Sierra Club and WildEarth Guardians in the 

United States District Court for the Northern District of California: Sierra Club et al. v. Jackson, 

No. 3:10-cv-04060-CRB (N.D. Cal.). A subsequent Modification to the Settlement Agreement 

specifies a deadline of May 22, 2015, for signature on the final action to respond to the Petition. 
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date back several decades. Aware of that fact, the EPA is committed to working closely with 

each of the affected states to develop approvable SIP submissions consistent with the guidance 

articulated in the updated SSM Policy in this final action. Section IX of this notice presents the 

EPA’s analysis of each specific SIP provision at issue in this action. The EPA’s review also 

involved interpretation of several relevant sections of the CAA. While the EPA has already 

developed and has been implementing the SSM Policy that is based on its interpretation of the 

CAA, this action provides the EPA an opportunity to update the SSM Policy and its basis in the 

CAA through notice and comment. To that end, section XI of this notice contains a restatement 

of the EPA’s SSM Policy as revised and updated for 2015. Also, supplementary to the February 

2013 proposal, the EPA provided a background memorandum to summarize the legal and 

administrative context for this action which is available in the docket for this rulemaking.5

 This 

final notice is intended to clarify how states can resolve the identified deficiencies in their SIPs 

as well as to provide all air agencies guidance as they develop SIPs in the future. 

In summary, the EPA is agreeing with the Petitioner that many of the identified SIP 

provisions are not permissible under the CAA. However, in some cases the EPA is instead 

concluding that an identified SIP provision is actually consistent with CAA requirements. In 

 

5 See Memorandum, “Statutory, Regulatory, and Policy Context for this Rulemaking,” 

February 4, 2013, in the rulemaking docket at EPA-HQ-OAR-2012-0322-0029. The EPA notes 

that with respect to the legal basis for affirmative defense provisions in SIPs, the Agency has 

revised its views as a result of a court decision, as explained in more detail in the SNPR. Thus, 

the portions of that background memorandum that concern affirmative defense provisions are no 

longer germane to this action. 
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addition, the EPA notes, this final action does not include a final finding of substantial 

inadequacy and SIP call for specific SIP provisions included in the February 2013 proposal for 

several air agencies. The state of Kentucky has already submitted, and the EPA has approved, 

SIP revisions that corrected the problematic provisions applicable in the Jefferson County 

(Louisville, Kentucky) area.6

 The state of Wyoming has already submitted, and the EPA has 

approved, SIP revisions that corrected the problematic provisions applicable statewide.7

 The 

state of North Dakota has likewise already submitted, and the EPA has approved, SIP revisions 

that corrected a portion of the problematic provisions applicable statewide.8

 

Of the 41 states for which SIP provisions were identified by the Petition or identified 

independently by the Agency in the SNPR, the EPA is issuing a SIP call for 37 states. The EPA 

is aware of other SSM-related SIP provisions that were not identified in the Petition but that may 

be inconsistent with the EPA’s interpretation of the CAA. For SIP provisions that have potential 

defects other than an impermissible affirmative defense, the EPA elected to focus on the 

provisions specifically raised in the Petition. The EPA may address these other provisions later 

in a separate notice-and-comment action. States are encouraged to consider the updated SSM 

Policy laid out in this final action in reviewing their own SIP provisions. With respect to 

affirmative defense provisions, however, the EPA elected to identify some additional provisions 

not included in the Petition because that is necessary to minimize potential confusion relating to 

 

6 See “Approval and Promulgation of Implementation Plans; Kentucky; Approval of Revisions to 

the Jefferson County Portion of the Kentucky SIP; Emissions During Startups, Shutdowns, and 

Malfunctions,” 79 FR 33101 (June 10, 2014). 

7 See “Approval and Promulgation of Implementation Plans; Wyoming; Revisions to the Air 

Quality Standards and Regulations,” 79 FR 62859 (October 21, 2014). 

8 See “Approval and Promulgation of Implementation Plans; North Dakota; Revisions to the Air 

Pollution Control Rules,” 79 FR 63045 (October 21, 2014). 
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other recent rulemakings and court decisions that pertain generally to affirmative defense 

provisions. Therefore, in order to give updated and comprehensive guidance with respect to 

affirmative defense provisions, the EPA has also addressed additional affirmative defense 

provisions in 17 states in the SNPR and in this final action. 

B. What the Petitioner Requested 

The Petition includes three interrelated requests concerning the treatment in SIPs of 

excess emissions by sources during periods of SSM. 

First, the Petitioner argued that SIP provisions providing an affirmative defense for 

monetary penalties for excess emissions in judicial proceedings are contrary to the CAA. Thus, 

the Petitioner advocated that the EPA should rescind its interpretation of the CAA expressed in 

the SSM Policy that allows appropriately drawn affirmative defense provisions in SIPs. The 

Petitioner made no distinction between affirmative defenses for excess emissions related to 

malfunction, startup or shutdown. Further, the Petitioner requested that the EPA issue a SIP call 

requiring states to eliminate all such affirmative defense provisions in existing SIPs. As 

explained later in this final notice, the EPA has decided to fully grant this request. Although the 

EPA initially proposed to grant in part and to deny in part this request in the February 2013 

proposal, a subsequent court decision concerning the legal basis for affirmative defense 

provisions under the CAA caused the Agency to reexamine this question. As a result, the EPA 

issued the SNPR to present its revised interpretation of the CAA with respect to this issue and to 

propose action on the Petition and on specific existing affirmative defense provisions in the SIPs 

of 17 states consistent with the reasoning of that court decision. In this final action, the EPA is 

revising its SSM Policy with respect to affirmative defenses for violations due to excess 

emissions that occur during startup, shutdown, malfunction or other modes of source operation. 
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The EPA believes that SIP provisions that function to alter the jurisdiction of the federal courts 

under CAA section 113 and section 304 to determine liability and to impose remedies are 

inconsistent with fundamental legal requirements of the CAA, especially with respect to the 

enforcement regime explicitly created by statute. 

Second, the Petitioner argued that many existing SIPs contain impermissible provisions, 

including automatic exemptions from applicable emission limitations during SSM events, 

director’s discretion provisions that in particular provide discretionary exemptions from 

applicable emission limitations during SSM events, enforcement discretion provisions that 

appear to bar enforcement by the EPA or citizens for such excess emissions and inappropriate 

affirmative defense provisions that are not consistent with the CAA or with the recommendations 

in the EPA’s SSM Policy. The Petitioner identified specific provisions in SIPs of 39 states that it 

considered inconsistent with the CAA and explained the basis for its objections to the provisions. 

As explained later in this final notice, the EPA agrees with the Petitioner that some of these 

existing SIP provisions are legally impermissible and thus finds such provisions “substantially 

inadequate”9

 to meet CAA requirements. Among the reasons for the EPA’s action is to eliminate 

SIP provisions that interfere with enforcement in a manner prohibited by the CAA. 

Simultaneously, where the EPA agrees with the Petitioner, the EPA is issuing a SIP call that 

directs the affected state to revise its SIP accordingly. For the remainder of the identified 

provisions, however, the EPA disagrees with the contentions of the Petitioner and is thus denying 

the Petition with respect to those provisions and taking no further action. The EPA’s action 

issuing the SIP calls on this portion of the Petition will assure that these SIPs comply with the 

 

9

 The term “substantially inadequate” is used in the CAA and is discussed in detail in section 

VIII.A of this notice. 
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fundamental requirements of the CAA with respect to the treatment of excess emissions during 

periods of SSM. The majority of the state-specific provisions affected by this SIP call action are 

inconsistent with the EPA’s longstanding interpretation of the CAA through multiple iterations 

of its SSM Policy. With respect to SIP provisions that include an affirmative defense for 

violations of SIP requirements, however, the EPA has revised its prior interpretation of the 

statute that would have allowed such provisions under certain very limited conditions. Based 

upon an evaluation of the relevant statutory provisions in light of more recent court decisions, the 

EPA is issuing a SIP call to address existing affirmative defense provisions that would operate to 

alter or eliminate the jurisdiction of courts to assess liability and impose remedies and that would 

thereby contradict explicit provisions of the CAA relating to judicial authority. 

Third, the Petitioner argued that the EPA should not rely on interpretive letters from 

states to resolve any ambiguity, or perceived ambiguity, in state regulatory provisions in SIP 

submissions. The Petitioner reasoned that all regulatory provisions should be clear and 

unambiguous on their face and that any reliance on interpretive letters to alleviate facial 

ambiguity in SIP provisions can lead to later problems with compliance and enforcement. 

Extrapolating from several instances in which the basis for the original approval of a SIP 

provision related to excess emissions during SSM events was arguably not clear, the Petitioner 

contended that the EPA should never use interpretive letters to resolve such ambiguities. As 

explained later in this proposal, the EPA acknowledges the concern of the Petitioner that 

provisions in SIPs should be clear and unambiguous. However, the EPA does not agree with the 

Petitioner that reliance on interpretive letters in a rulemaking context is never appropriate. 

Without the ability to rely on a state’s interpretive letter that can in a timely way clarify 

perceived ambiguity in a provision in a SIP submission, however small that ambiguity may be, 
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the EPA may have no recourse other than to disapprove the state’s SIP submission. Thus, the 

EPA is denying the request that actions on SIP submissions never rely on interpretive letters. 

Instead, the EPA explains how proper documentation of reliance on interpretive letters in noticeand-comment rulemaking nevertheless addresses the practical concerns of the Petitioner. 

C. To which air agencies does this rulemaking apply and why? 

In general, the final rule may be of interest to all air agencies because the EPA is 

clarifying, restating and revising its longstanding SSM Policy with respect to what the CAA 

requires concerning SIP provisions relevant to excess emissions during periods of SSM. For 

example, the EPA is granting the Petitioner’s request that the EPA rescind its prior interpretation 

of the CAA that, as stated in prior guidance in the SSM Policy, allowed appropriately drawn 

affirmative defense provisions applicable to malfunctions. The EPA is also reiterating, clarifying 

or revising its prior guidance with respect to several other issues related to SIP provisions 

applicable to SSM events in order to ensure that future SIP submissions, not limited to those that 

affected states make in response to this action, are fully consistent with the CAA. For example, 

the EPA is reiterating and clarifying its prior guidance concerning how states may elect to 

replace existing exemptions for excess emissions during SSM events with properly developed 

alternative emission limitations that apply to the affected sources during startup, shutdown or 

other normal modes of source operation (i.e., that apply to excess emissions during those normal 

modes of operation as opposed to during malfunctions). This action also addresses the use of 

interpretive letters for purposes of resolving an actual or perceived ambiguity in a SIP 

submission during the EPA’s evaluation of the SIP revision at issue. 

In addition, this final action is directly relevant to the states with SIP provisions relevant 

to excess emissions that the EPA has determined are inconsistent with CAA requirements or with 
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the EPA’s interpretation of those requirements in the SSM Policy. In this final action, the EPA is 

either granting or denying the Petition with respect to the specific existing SIP provisions in each 

of 39 states identified by the Petitioner as allegedly inconsistent with the CAA. The 39 states (for 

which the Petitioner identified SIP provisions applicable in 46 statewide and local jurisdictions 

and no tribal areas)10 are listed in table 1, “List of States with SIP Provisions for Which the EPA 

Either Grants or Denies the Petition, in Whole or in Part.” After evaluating the Petition, the EPA 

is granting the petition with respect to one or more provisions in 35 of the 39 states listed, and 

these are the states for which the action on the Petition, according to table 1, is either “Grant” or 

“Partially grant, partially deny.” Conversely, the EPA is denying the petition with respect to all 

provisions that the Petitioner identified in 4 of the 39 states, and these (Idaho, Nebraska, Oregon 

and Wyoming) are the states for which the final action on the Petition, according to table 1, is 

“Deny.” 

Table 1. List of States with SIP Provisions for Which the EPA Either Grants or Denies the 

Petition, in Whole or in Part 

EPA 

Region State Final action on petition 

I Maine ......................................................... Grant 

New Hampshire ......................................... Partially grant, partially deny 

Rhode Island .............................................. Grant 

II New Jersey ................................................. Partially grant, partially deny 

III Delaware .................................................... Grant 

District of Columbia .................................. Partially grant, partially deny 

Virginia ...................................................... Grant 

West Virginia ............................................. Grant 

 

10 The state has the primary responsibility to implement SIP obligations, pursuant to CAA 

section 107(a). However, as CAA section 110(a)(2)(E) allows, a state may authorize and rely on 

a local or regional government, agency or instrumentality to carry out the SIP or a portion of the 

SIP within its jurisdiction. As a result, some of the SIP provisions at issue in this rulemaking 

apply to specific portions of a state. Thus, in certain states, submission of a corrective SIP 

revision may involve rulemaking in more than one jurisdiction. 
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IV Alabama ..................................................... Grant 

Florida ........................................................ Grant 

Georgia ...................................................... Grant 

Kentucky .................................................... Partially grant, partially deny 

Mississippi ................................................. Grant 

North Carolina ........................................... Grant 

South Carolina ........................................... Partially grant, partially deny 

Tennessee ................................................... Grant 

V Illinois ........................................................ Grant 

Indiana ....................................................... Grant 

Michigan .................................................... Grant 

Minnesota .................................................. Grant 

Ohio ........................................................... Partially grant, partially deny 

VI Arkansas .................................................... Grant 

Louisiana ................................................... Grant 

New Mexico .............................................. Grant 

Oklahoma ................................................... Grant 

VII Iowa ........................................................... Partially grant, partially deny 

Kansas ........................................................ Grant 

Missouri ..................................................... Partially grant, partially deny 

Nebraska .................................................... Deny 

VIII Colorado .................................................... Grant 

Montana ..................................................... Grant 

North Dakota ............................................. Partially grant, partially deny 

South Dakota ............................................. Grant 

Wyoming ................................................... Deny 

IX Arizona ...................................................... Partially grant, partially deny 

X Alaska ........................................................ Grant 

Idaho .......................................................... Deny 

Oregon ....................................................... Deny 

Washington ................................................ Grant 

For each state for which the final action on the Petition is either “Grant” or “Partially 

grant, partially deny,” the EPA finds that certain specific provisions in each state’s SIP are 

substantially inadequate to meet CAA requirements for the reason that these provisions are 

inconsistent with the CAA with regard to how the state treats excess emissions from sources 

during periods of SSM. With respect to the affirmative defense provisions identified in the 

Petition, the EPA finds that they improperly impinge upon the statutory jurisdiction of the courts 
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to determine liability and impose remedies for violations of SIP emission limitations. The EPA 

believes that certain specific provisions in these SIPs fail to meet fundamental statutory 

requirements intended to attain and maintain the NAAQS, protect prevention of significant 

deterioration (PSD) increments and improve visibility. Equally importantly, the EPA believes 

that the same provisions may undermine the ability of states, the EPA and the public to enforce 

emission limitations in the SIP that have been relied upon to ensure attainment or maintenance of 

the NAAQS or to meet other CAA requirements. 

For each state for which the final action on the Petition is either “Grant” or “Partially 

grant, partially deny,” the EPA is also in this final action calling for a SIP revision as necessary 

to correct the identified deficient provisions. The SIP revisions that the states are directed to 

make will rectify a number of different types of defects in existing SIPs, including automatic 

exemptions from emission limitations, impermissible director’s discretion provisions, 

enforcement discretion provisions that have the effect of barring enforcement by the EPA or 

through a citizen suit and affirmative defense provisions that are inconsistent with CAA 

requirements. A corrective SIP revision addressing automatic or impermissible discretionary 

exemptions will ensure that excess emissions during periods of SSM are treated in accordance 

with CAA requirements. Similarly, a corrective SIP revision addressing ambiguity in who may 

enforce against violations of these emission limitations will also ensure that CAA requirements 

to provide for enforcement are met. A SIP revision to remove affirmative defense provisions will 

assure that the SIP provision does not purport to alter or eliminate the jurisdiction of federal 

courts to assess liability or to impose remedies consistent with the statutory authority provided in 

CAA section 113 and section 304. The particular provisions for which the EPA is requiring SIP 

revisions are summarized in section IX of this notice. Many of these provisions were added to 
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the respective SIPs many years ago and have not been the subject of action by the state or the 

EPA since. 

For each of the states for which the EPA is denying or is partially denying the Petition, 

the EPA finds that the particular provisions identified by the Petitioner are not substantially 

inadequate to meet the requirements pursuant to CAA section 110(k)(5), because the provisions: 

(i) are, as they were described in the Petition and as they appear in the existing SIP, consistent 

with the requirements of the CAA; or (ii) are, as they appear in the existing SIP after having been 

revised subsequent to the date of the Petition, consistent with the requirements of the CAA; or 

(iii) have, subsequent to the date of the Petition, been removed from the SIP. Thus, in this final 

rule, the EPA is taking no action to issue a SIP call with respect to those states for those 

particular SIP provisions. 

In addition to evaluating specific SIP provisions identified in the Petition, the EPA has 

independently evaluated additional affirmative defense provisions in the SIPs of six states 

(applicable in nine statewide and local jurisdictions).11 As explained in the SNPR, the EPA 

determined that this approach was necessary in order to take into consideration recent judicial 

decisions concerning affirmative defense provisions and CAA requirements. As the result of this 

 

11 The six states in which the EPA independently evaluated affirmative defense provisions are: 

California; South Carolina, New Mexico, Texas, Washington and West Virginia. The EPA 

evaluated the New Mexico SIP with respect to provisions applicable to the state and 

Albuquerque-Bernalillo County. The EPA evaluated the Washington SIP with respect to 

provisions applicable to the state, the Energy Facility Site Evaluation Council and the Southwest 

Clean Air Agency. 
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evaluation, the EPA finds that specific affirmative defense provisions in 17 states (applicable in 

23 statewide and local jurisdictions) are substantially inadequate to meet CAA requirements for 

the reason that these provisions impinge upon the statutory jurisdiction of the federal courts to 

determine liability and impose remedies for violations of SIP emission limitations.12 By 

improperly impinging upon the jurisdiction of the federal courts, the EPA believes, these 

provisions fail to meet fundamental statutory requirements intended to attain and maintain the 

NAAQS, protect PSD increments and improve visibility. As with the affirmative defense 

provisions identified in the Petition, the EPA believes that these provisions may undermine the 

ability of states, the EPA and the public to enforce emission limitations in the SIP that have been 

relied upon to ensure attainment or maintenance of the NAAQS or to meet other CAA 

requirements. 

In this final action, the EPA is issuing a SIP call to each of 37 states (for provisions 

applicable in 46 statewide and local jurisdictions) with respect to these provisions. The 37 states 

are listed in table 2, “List of All States with SIP Provisions Subject to SIP Call.” The EPA 

emphasizes that this SIP call action pertains to the specific SIP provisions identified and 

 

12 The 17 states for which the EPA finds that specific affirmative defense provisions are 

substantially inadequate to meet CAA requirements are counted as follows: The EPA evaluated 

affirmative defense provisions identified by the Petitioner for 14 states: Alaska; Arizona; 

Arkansas; Colorado; District of Columbia; Georgia; Illinois; Indiana; Kentucky; Michigan; 

Mississippi; New Mexico; Virginia; and Washington. The EPA evaluated affirmative defense 

provisions that it independently identified among two states identified by the Petitioner: South 

Carolina; and West Virginia. Further, the EPA independently identified and evaluated 

affirmative defense provisions in two states that were not included in the Petition: California; and 

Texas. In the final action, the EPA is finding one or more affirmative defense provisions to be 

substantially inadequate in all but one of the 18 states for which the EPA evaluated affirmative 

defense provisions; for one state, Kentucky, the affirmative defense provision, which was 

applicable in Jefferson County, was corrected prior to the EPA’s issuing its SNPR. 
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discussed in section IX of this document. The actions required of individual states in response to 

this SIP call action are discussed in more detail in section IX of this action. 

Table 2. List of All States With SIP Provisions Subject to SIP Call 

EPA 

Region State Area 

I Maine ......................................................... State 

 New Hampshire .......................................... State 

 Rhode Island .............................................. State 

II New Jersey ................................................. State 

III Delaware .................................................... State 

 District of Columbia ................................... State 

 Virginia ...................................................... State 

 West Virginia ............................................. State 

IV Alabama ..................................................... State 

 Florida ........................................................ State 

 Georgia ....................................................... State 

 Kentucky .................................................... State 

 Mississippi ................................................. State 

 North Carolina ............................................ State and Forsyth County 

 South Carolina ............................................ State 

Tennessee ................................................... State, Knox County and 

Shelby County 

V Illinois ........................................................ State 

 Indiana ........................................................ State 

 Michigan .................................................... State 

 Minnesota ................................................... State 

 Ohio ............................................................ State 

VI Arkansas ..................................................... State 

 Louisiana .................................................... State 

New Mexico ............................................... State and AlbuquerqueBernalillo County 

 Oklahoma ................................................... State 

 Texas .......................................................... State 

VII Iowa ............................................................ State 

 Kansas ........................................................ State 

 Missouri ..................................................... State 

VIII Colorado ..................................................... State 

 Montana ..................................................... State 

 North Dakota .............................................. State 

 South Dakota .............................................. State 

IX Arizona ....................................................... State and Maricopa County 
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California ................................................... Eastern Kern APCD, Imperial 

County APCD and San 

Joaquin Valley Unified 

APCD 

X Alaska ......................................................... State 

Washington ................................................ State, Energy Facility Site 

Evaluation Council and 

Southwest Clean Air Agency 

D. What are the next steps for states that are receiving a finding of substantial inadequacy 

and a SIP call? 

The EPA is finalizing a finding of substantial inadequacy and issuing a SIP call for the 

states listed in table 2 (see section II.C of this document). The EPA is also establishing a 

deadline by which these states must make a SIP submission to rectify the specifically identified 

deficiencies in their respective SIPs. Pursuant to CAA section 110(k)(5), the EPA has authority 

to set a SIP submission deadline that is up to 18 months from the date of the final finding of 

substantial inadequacy. After considering comment on this issue, the EPA is in this final rule 

establishing a deadline of November 22, 2016, by which each affected state is to respond to the 

SIP call. The deadline falls 18 months from the date of signature and dissemination of this final 

finding of substantial inadequacy. Thereafter, the EPA will review the adequacy of that new SIP 

submission in accordance with the CAA requirements of sections 110(a), 110(k)(3), 110(l) and 

193, including the EPA’s interpretation of the CAA reflected in the SSM Policy as clarified and 

updated through this rulemaking. The EPA believes that states should be provided the maximum 

time allowable under CAA section 110(k)(5) in order to have sufficient time to make appropriate 

SIP revisions following their own SIP development process. Such a schedule will allow for the 

necessary SIP development process to correct the deficiencies yet still achieve the necessary SIP 
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improvements as expeditiously as practicable consistent with the maximum time allowed by 

statute. 

E. What are potential impacts on affected states and sources? 

The issuance of a SIP call requires an affected state to take action to revise its SIP. That 

action by the state may, in turn, affect sources as described later in this notice. The states that are 

receiving a SIP call in this final action will in general have options as to exactly how to revise 

their SIPs. In response to a SIP call, a state retains broad discretion concerning how to revise its 

SIP, so long as that revision is consistent with the requirements of the CAA. Some provisions 

that are affected by this SIP call, for example an automatic exemption provision, have to be 

removed entirely and an affected source could no longer depend on the exemption to avoid all 

liability for excess emissions during SSM events. Some other provisions, for example a 

problematic enforcement discretion provision, could either be removed entirely from the SIP or 

retained if revised appropriately to apply only to state enforcement personnel, in accordance with 

the EPA’s interpretation of the CAA as described in the EPA’s SSM Policy. The EPA notes that 

if a state removes a SIP provision that pertains to the state’s exercise of enforcement discretion, 

this removal would not affect the ability of the state to apply its traditional enforcement 

discretion in its enforcement program. It would merely make the exercise of such discretion 

case-by-case in nature, as is the normal form of such discretion. 

In addition, affected states may choose to consider reassessing particular emission 

limitations, for example to determine whether those emission limitations can be revised such that 

well-managed emissions during planned operations such as startup and shutdown would not 

exceed the revised emission limitation, while still protecting air quality and meeting other 

applicable CAA requirements. Such a revision of an emission limitation will need to be 
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submitted as a SIP revision for the EPA approval if the existing limitation to be changed is 

already included in the SIP or if the existing SIP relies on the particular existing emission 

limitation to meet a CAA requirement. In such instances, the EPA would review the SIP revision 

for consistency with all applicable CAA requirements. A state that chooses to revise particular 

emission limitations, in addition to removing or revising the aspect of the existing SIP provision 

that is inconsistent with CAA requirements, could include those revisions in the same SIP 

submission that addresses the SSM provisions identified in the SIP call, or it could submit them 

separately. 

The implications for a regulated source in a given state, in terms of whether and how it 

would potentially have to change its equipment or practices in order to operate with emissions 

that comply with the revised SIP, will depend on the nature and frequency of the source’s SSM 

events and how the state has chosen to revise the SIP to address excess emissions during SSM 

events. The EPA recognizes that after all the responsive SIP revisions are in place and are being 

implemented by the states, some sources may need to take steps to control emissions better so as 

to comply with emission limitations continuously, as required by the CAA, or to increase 

durability of components and monitoring systems to detect and manage malfunctions promptly. 

The EPA Regional Offices will work with states to help them understand their options 

and the potential consequences for sources as the states prepare their SIP revisions in response to 

this SIP call. 

F. What happens if an affected state fails to meet the SIP submission deadline? 

If, in the future, the EPA finds that a state that is subject to this SIP call action has failed 

to submit a complete SIP revision as required, or the EPA disapproves such a SIP revision, then 

the finding or disapproval would trigger an obligation for the EPA to impose a federal 
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implementation plan (FIP) within 24 months after that date. That FIP obligation would be 

discharged without promulgation of a FIP only if the state makes and the EPA approves the 

called-for SIP submission. In addition, if a state fails to make the required SIP revision, or if the 

EPA disapproves the required SIP revision, then either event can also trigger mandatory 18-

month and 24-month sanctions clocks under CAA section 179. The two sanctions that apply 

under CAA section 179(b) are the 2-to-1 emission offset requirement for all new and modified 

major sources subject to the nonattainment new source review program and restrictions on 

highway funding. More details concerning the timing and process of the SIP call, and potential 

consequences of the SIP call, are provided in section VIII of this notice. 

G. What is the status of SIP provisions affected by this SIP call action in the interim period 

starting when the EPA promulgates the final SIP call and ending when the EPA approves the 

required SIP revision? 

When the EPA issues a final SIP call to a state, that action alone does not cause any 

automatic change in the legal status of the existing affected provision(s) in the SIP. During the 

time that the state takes to develop a SIP revision in response to the SIP call and the time that the 

EPA takes to evaluate and act upon the resulting SIP submission from the state pursuant to CAA 

section 110(k), the existing affected SIP provision(s) will remain in place. The EPA notes, 

however, that the state regulatory revisions that the state has adopted and submitted for SIP 

approval will most likely be already in effect at the state level during the pendency of the EPA’s 

evaluation of and action upon the new SIP submission. 

The EPA recognizes that in the interim period, there may continue to be instances of 

excess emissions that adversely affect attainment and maintenance of the NAAQS, interfere with 

PSD increments, interfere with visibility and cause other adverse consequences as a result of the 
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impermissible provisions. The EPA is particularly concerned about the potential for serious 

adverse consequences for public health in this interim period during which states, the EPA and 

sources make necessary adjustments to rectify deficient SIP provisions and take steps to improve 

source compliance. However, given the need to resolve these longstanding SIP deficiencies in a 

careful and comprehensive fashion, the EPA believes that providing sufficient time consistent 

with statutory constraints for these corrections to occur will ultimately be the best course to meet 

the ultimate goal of eliminating the inappropriate SIP provisions and replacing them with 

provisions consistent with CAA requirements. 

III. Statutory, Regulatory and Policy Background 

The Petition raised issues related to excess emissions from sources during periods of 

SSM, and to the correct approach to these excess emissions in SIPs. In this context, “excess 

emissions” are air emissions that exceed the otherwise applicable emission limitations in a SIP, 

i.e., emissions that would be violations of such emission limitations. The question of how to 

address excess emissions correctly during SSM events has posed a challenge since the inception 

of the SIP program in the 1970s. The primary objective of state and federal regulators is to 

ensure that sources of emissions are subject to appropriate emission controls as necessary in 

order to attain and maintain the NAAQS, protect PSD increments, improve visibility and meet 

other statutory requirements. Generally, this is achieved through enforceable emission limitations 

on sources that apply, as required by the CAA, continuously. 

Several key statutory provisions of the CAA are relevant to the EPA’s evaluation of the 

Petition. These provisions relate generally to the basic legal requirements for the content of SIPs, 

the authority and responsibility of air agencies to develop such SIPs and the EPA’s authority and 

responsibility to review and approve SIP submissions in the first instance, as well as the EPA’s 
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authority to require improvements to a previously approved SIP if the EPA later determines that 

to be necessary for a SIP to meet CAA requirements. In addition, the Petition raised issues that 

pertain to enforcement of provisions in a SIP. The enforcement issues relate generally to what 

constitutes a violation of an emission limitation in a SIP, who may seek to enforce against a 

source for that violation, and whether the violator should be subject to monetary penalties as well 

as other forms of judicial relief for that violation. 

The EPA has a longstanding interpretation of the CAA with respect to the treatment of 

excess emissions during periods of SSM in SIPs. This statutory interpretation has been 

expressed, reiterated and elaborated upon in a series of guidance documents issued in 1982, 

1983, 1999 and 2001. In addition, the EPA has applied this interpretation in individual 

rulemaking actions in which the EPA: (i) approved SIP submissions that were consistent with the 

EPA’s interpretation;13 (ii) disapproved SIP submissions that were not consistent with this 

interpretation;14 (iii) itself promulgated regulations in FIPs that were consistent with this 

 

13 See “Approval and Promulgation of Implementation Plans; Texas; Excess Emissions During 

Startup, Shutdown, Maintenance, and Malfunction Activities,” 75 FR 68989 (November 10, 

2010). 

14 See “Approval and Promulgation of State Implementation Plans; Michigan,” 63 FR 8573 

(February 20, 1998). 
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interpretation;15 or (iv) issued a SIP call requiring a state to revise an impermissible SIP 

provision.16 

The EPA’s SSM Policy is a policy statement and thus constitutes guidance. As guidance, 

the SSM Policy does not bind states, the EPA or other parties, but it does reflect the EPA’s 

interpretation of the statutory requirements of the CAA. The EPA’s evaluation of any SIP 

provision, whether prospectively in the case of a new provision in a SIP submission or 

retrospectively in the case of a previously approved SIP submission, must be conducted through 

a notice-and-comment rulemaking in which the EPA will determine whether or not a given SIP 

provision is consistent with the requirements of the CAA and applicable regulations.17 

The Petition raised issues related to excess emissions from sources during periods of 

SSM, and the consequences of failing to address these emissions correctly in SIPs. In broad 

terms, the Petitioner expressed concerns that the exemptions for excess emissions and the other 

types of alleged deficiencies in existing SIP provisions “undermine the emission limits in SIPs 

and threaten states’ abilities to achieve and maintain the NAAQS, thereby threatening public 

health and public welfare, which includes agriculture, historic properties and natural areas.”18

The Petitioner asserted that such exemptions for SSM events are “loopholes” that can allow 

dramatically higher amounts of emissions and that these emissions “can swamp the amount of 

pollutants emitted at other times.”19 In addition, the Petitioner argued that these automatic and 

 

15 See “Federal Implementation Plan for the Billings/Laurel, MT, Sulfur Dioxide Area,” 73 FR 

21418 (April 21, 2008). 

16 See “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah State 

Implementation Plan Revision,” 76 FR 21639 (April 18, 2011). 

17 See generally Catawba County, North Carolina et al. v. EPA, 571 F.3d 20, 33–35 (D.C. Cir. 

2009) (upholding the EPA’s process for developing and applying its guidance to designations). 

18 Petition at 2. 

19 Petition at 12. 
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discretionary exemptions, as well as other SIP provisions that interfere with the enforcement 

structure of the CAA, undermine the objectives of the CAA. 

The EPA notes that the types of SIP deficiencies identified in the Petition are not legal 

technicalities. Compliance with the applicable requirements is intended to achieve the air quality 

protection and improvement purposes and objectives of the CAA. The EPA believes that the 

results of automatic and discretionary exemptions in SIP provisions, and of other provisions that 

interfere with effective enforcement of SIPs, are real-world consequences that adversely affect 

public health. Commenters on the February 2013 proposal provided illustrative examples of 

impacts that these types of SIP provisions have on the communities located near sources that rely 

on automatic or discretionary exemptions for excess emissions during SSM events, rather than 

by designing, operating and maintaining their sources to meet the applicable emission 

limitations. These comments also illustrated the ways in which such exemptions, incorrect 

enforcement discretion provisions and affirmative defense provisions have interfered with the 

enforcement structure of the CAA by raising inappropriate impediments to enforcement by 

states, the EPA, or citizens. 

The EPA’s memorandum providing a detailed discussion of the statutory, regulatory and 

policy background for this action can be found in the docket for this rulemaking.20 

 

20 See Memorandum, “Statutory, Regulatory, and Policy Context for this Rulemaking,” February 

4, 2013, in the rulemaking docket at EPA-HQ-OAR-2012-0322-0029. 
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IV. Final Action in Response to Request to Rescind the EPA Policy Interpreting the 

CAA to Allow Affirmative Defense Provisions 

A. What the Petitioner Requested 

The Petitioner’s first request was for the EPA to rescind its SSM Policy element 

interpreting the CAA to allow affirmative defense provisions in SIPs for excess emissions during 

SSM events.21 Related to this request, the Petitioner also asked the EPA: (i) to find that SIPs 

containing an affirmative defense to monetary penalties for excess emissions during SSM events 

are substantially inadequate because they do not comply with the CAA; and (ii) to issue a SIP 

call pursuant to CAA section 110(k)(5) to require each such state to revise its SIP.22

Alternatively, if the EPA denies these two related requests, the Petitioner asked the EPA: (i) to 

require states with SIPs that contain such affirmative defense provisions to revise them so that 

they are consistent with the EPA’s 1999 SSM Guidance for excess emissions during SSM 

events; and (ii) to issue a SIP call pursuant to CAA section 110(k)(5) to states with provisions 

inconsistent with the EPA’s interpretation of the CAA.23 

The Petitioner requested that the EPA rescind its SSM Policy element interpreting the 

CAA to allow SIPs to include affirmative defenses for violations due to excess emissions during 

any type of SSM events because the Petitioner contended there is no legal basis for the Agency’s 

interpretation. Specifically, the Petitioner cited to two statutory grounds, CAA sections 113(b) 

and 113(e), related to the type of judicial relief available in an enforcement proceeding and to the 

factors relevant to the scope and availability of such relief, that the Petitioner claimed would bar 

 

21 Petition at 11. 

22 Id. 23 Petition at 12. 
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the approval of any type of affirmative defense provision in SIPs. The Petitioner drew no 

distinction between affirmative defense provisions for malfunctions versus affirmative defense 

provisions for startup and shutdown or other normal modes of operation; in the Petitioner’s view 

all are equally inconsistent with CAA requirements. 

In the Petitioner’s view, the CAA “unambiguously grants jurisdiction to the district 

courts to determine penalties that should be assessed in an enforcement action involving the 

violation of an emissions limit.”24 The Petitioner first argued that in any judicial enforcement 

action in a district court, CAA section 113(b) provides that “such court shall have jurisdiction to 

restrain such violation, to require compliance, to assess such penalty, . . . and to award any other 

appropriate relief.” The Petitioner reasoned that the EPA’s SSM Policy is therefore 

fundamentally inconsistent with the CAA because it purports to remove the discretion and 

authority of the district courts to assess monetary penalties for violations if a source is shielded 

from monetary penalties under an affirmative defense provision in the approved SIP.25 The 

Petitioner concluded that the EPA’s interpretation of the CAA in the SSM Policy element 

allowing any affirmative defenses is impermissible “because the inclusion of an affirmative 

defense provision in a SIP limits the courts’ discretion—granted by Congress—to assess 

penalties for Clean Air Act violations.”26 

Second, in reliance on CAA section 113(e)(1), the Petitioner argued that in a judicial 

enforcement action in a district court, the statute explicitly specifies a list of factors that the court 

is to consider in assessing penalties.27 The Petitioner argued that the EPA’s SSM Policy 

 

24 Petition at 10. 

25 Id. 26 Id. 27 Petition at 11. 
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authorizes states to create affirmative defense provisions with criteria for monetary penalties that 

are inconsistent with the factors that the statute specifies and that the statute explicitly directs 

courts to weigh in any judicial enforcement action. By specifying particular factors for courts to 

consider, the Petitioner reasoned, Congress has already definitively spoken to the question of 

what factors are germane in assessing monetary penalties under the CAA for violations. The 

Petitioner concluded that the EPA has no authority to allow a state to include an affirmative 

defense provision in a SIP with different criteria to be considered in awarding monetary penalties 

because “[p]reventing the district courts from considering these statutory factors is not a 

permissible interpretation of the Clean Air Act.”28 A more detailed explanation of the 

Petitioner’s arguments appears in the 2013 February proposal.29 

B. What the EPA Proposed 

In the February 2013 proposal, consistent with its interpretation of the Act at that time, 

the EPA proposed to deny in part and to grant in part the Petition with respect to this overarching 

issue. As a revision to the SSM Policy as embodied in the 1999 SSM Guidance, the EPA 

proposed a distinction between affirmative defenses for unplanned events such as malfunctions 

and planned events such as startup and shutdown. The EPA explained the basis for its initial 

proposed action in detail, including why the Agency then believed that there was a statutory 

basis for narrowly drawn affirmative defense provisions that met certain criteria applicable to 

malfunction events but no such statutory basis for affirmative defense provisions applicable to 

startup and shutdown events. In the February 2013 proposal, the EPA also proposed to deny in 

part and to grant in part the Petition with respect to specific affirmative defense provisions in the 

 

28 Petition at 11. 

29 See February 2013 proposal, 78 FR 12459 at 12468 (February 22, 2013). 
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SIPs of various states identified in the Petition consistent with that interpretation. With respect to 

these specific existing SIP provisions, the EPA distinguished between those provisions that were 

consistent with the Agency’s interpretation of the CAA as set forth in 1999 SSM Guidance and 

were limited to malfunction events and other affirmative defense provisions that were not limited 

to malfunctions or otherwise not consistent with the Agency’s interpretation of the CAA and 

included one or more deficiencies. 

Subsequent to the February 2013 proposal, however, a judicial decision by the U.S. Court 

of Appeals for the District of Columbia Circuit (D.C. Circuit) in NRDC v. EPA concerning the 

legal basis for affirmative defense provisions in the EPA’s own regulations caused the Agency to 

reconsider the legal basis for any affirmative defense provisions in SIPs, regardless of the type of 

events to which they apply, the criteria they may contain or the types of judicial remedies they 

purport to limit or eliminate.30 Thus, the EPA issued an SNPR to revise its proposed response to 

the Petition with respect to whether affirmative defense provisions in SIPs are consistent with 

fundamental legal requirements of the CAA.31 In the SNPR, the EPA also revised its proposed 

response related to each of the specific affirmative defense provisions identified in the Petition. 

Changes to the proposed response included revision of the basis for the proposed finding of 

substantial inadequacy for many of the provisions (to incorporate the EPA’s revised 

interpretation of the CAA into that basis). Other changes to the proposed response included 

reversal of the proposed denial of the Petition for some provisions that the Agency previously 

believed to be consistent with CAA requirements but subsequently determined were not 

authorized by the Act under the analysis prompted by the NRDC v. EPA decision. In order to 

 

30 See NRDC v. EPA, 749 F.3d 1055 (D.C. Cir. 2014). 

31 See SNPR, 79 FR 55919 (September 17, 2014). 
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provide comprehensive guidance to all states concerning affirmative defense provisions in SIPs 

and to avoid confusion that may arise due to recent court decisions relevant to such provisions 

under the CAA, the EPA also addressed additional existing SIP affirmative defense provisions of 

which it was aware although the provisions were not specifically identified in the Petition. The 

EPA initially examined the specific affirmative defense provisions identified by the Petitioner in 

14 states but subsequently broadened its review to include additional provisions in four states, 

including two states that were not included in the Petition. Most importantly, the EPA provided a 

detailed explanation in the SNPR as to why it now believes that the logic of the court in the 

NRDC v. EPA decision vacating the affirmative defense in an Agency emission limitation under 

CAA section 112 likewise extends to affirmative defense provisions in SIPs. 

C. What Is Being Finalized in This Action 

The EPA is taking final action to grant the Petition on the request to rescind its SSM 

Policy element that interpreted the CAA to allow states to elect to create affirmative defense 

provisions in SIPs. The EPA is also taking final action to grant the Petition on the request to 

make a finding of substantial inadequacy and to issue SIP calls for specific existing SIP 

provisions that include an affirmative defense as identified in the SNPR. The specific SIP 

provisions at issue are discussed in section IX of this notice. These existing affirmative defense 

provisions include some provisions that the EPA had previously determined were consistent with 

the CAA as interpreted in the 1999 SSM Guidance and other provisions that were not consistent 

even with that interpretation of the CAA. As explained in the SNPR, the EPA has now concluded 

that the enforcement structure of the CAA, embodied in section 113 and section 304, precludes 

any affirmative defense provisions that would operate to limit a court’s jurisdiction or discretion 

to determine the appropriate remedy in an enforcement action. These provisions are not 
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appropriate under the CAA, no matter what type of event they apply to, what criteria they 

contain or what forms of remedy they purport to limit or eliminate. 

The EPA is revising its interpretation of the CAA with respect to affirmative defenses 

based upon a reevaluation of the statutory provisions that pertain to enforcement of SIP 

provisions in light of recent court opinions. Section 113(b) provides courts with explicit 

jurisdiction to determine liability and to impose remedies of various kinds, including injunctive 

relief, compliance orders and monetary penalties, in judicial enforcement proceedings. This grant 

of jurisdiction comes directly from Congress, and the EPA is not authorized to alter or eliminate 

this jurisdiction under the CAA or any other law. With respect to monetary penalties, CAA 

section 113(e) explicitly includes the factors that courts and the EPA are required to consider in 

the event of judicial or administrative enforcement for violations of CAA requirements, 

including SIP provisions. Because Congress has already given federal courts the jurisdiction to 

determine what monetary penalties are appropriate in the event of judicial enforcement for a 

violation of a SIP provision, neither the EPA nor states can alter or eliminate that jurisdiction by 

superimposing restrictions on that jurisdiction and discretion granted by Congress to the courts. 

Affirmative defense provisions by their nature purport to limit or eliminate the authority of 

federal courts to determine liability or to impose remedies through factual considerations that 

differ from, or are contrary to, the explicit grants of authority in section 113(b) and section 

113(e). Accordingly, pursuant to section 110(k) and section 110(l), the EPA cannot approve any 

such affirmative defense provision in a SIP. If such an affirmative defense provision is included 

in an existing SIP, the EPA has authority under section 110(k)(5) to require a state to remove that 

provision. 
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States have great discretion to devise SIP provisions, but they do not have discretion to 

create provisions that contradict fundamental legal requirements of the CAA. The jurisdiction of 

federal courts to determine liability and to impose statutory remedies for violations of SIP 

emission limitations is one such fundamental requirement. The court in the recent NRDC v. EPA

decision did not remand the regulation to the EPA for better explanation of the legal basis for an 

affirmative defense; the court instead vacated the affirmative defense and indicated that there 

could be no valid legal basis for such a provision because it contradicted fundamental 

requirements of the CAA concerning the jurisdiction of courts in judicial enforcement of CAA 

requirements. A more detailed explanation of the EPA’s basis for determining that affirmative 

defense provisions in SIPs are similarly contrary to the requirements of the CAA appears in the 

SNPR.32 

Couching an affirmative defense provision in terms of merely defining whether or not the 

emission limitation applies and thus whether or not there is a “violation,” as suggested by some 

commenters, is also problematic. If there is no “violation” when certain criteria or conditions for 

an “affirmative defense” are met, then there is in effect no emission limitation that applies when 

the criteria or conditions are met; the affirmative defense thus operates to create an exemption 

from the emission limitation. As explained in the February 2013 proposal, the CAA requires that 

emission limitations must apply continuously and cannot contain exemptions, conditional or 

otherwise. This interpretation is consistent with the decision in Sierra Club v. Johnson 

concerning the term “emission limitation” in section 302(k). Characterizing the exemptions as an 

 

32 See 79 FR 55919 at 12931–34 (September 17, 2014). 
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“affirmative defense” runs afoul of the requirement that emission limitations must apply 

continuously. 

The EPA recognizes that the original policy objectives behind states’ affirmative defense 

provisions were likely well-intentioned, e.g., to encourage better source design, maintenance and 

operation through the incentive of being shielded from certain statutory remedies for violations 

under certain specified conditions. Nevertheless, creation of SIP provisions that would operate to 

limit or eliminate the jurisdiction of courts to determine liability or to impose remedies provided 

for by statute is inconsistent with the enforcement structure of the CAA. The EPA emphasizes 

that the absence of an affirmative defense provision in a SIP, whether as a freestanding generally 

applicable provision or as a specific component of a particular emission limitation, does not 

mean that all exceedances of SIP emission limitations will automatically be subject to 

enforcement or automatically be subject to imposition of particular remedies. Pursuant to the 

CAA, all parties with authority to bring an enforcement action to enforce SIP provisions (i.e., the 

state, the EPA or any parties who qualify under the citizen suit provision of section 304) have 

enforcement discretion that they may exercise as they deem appropriate in any given 

circumstances. For example, if the event that causes excess emissions is an actual malfunction 

that occurred despite reasonable care by the source operator to avoid malfunctions, then each of 

these parties may decide that no enforcement action is warranted. In the event that any party 

decides that an enforcement action is warranted, then it has enforcement discretion with respect 

to what remedies to seek from the court for the violation (e.g., injunctive relief, compliance 

order, monetary penalties or all of the above), as well as the type of injunctive relief and/or 
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amount of monetary penalties sought.33 Further, courts have the discretion under section 113 to 

decline to impose penalties or injunctive relief in appropriate cases as explained below. 

Similarly, the absence of an affirmative defense provision in a SIP does not alter the legal 

rights of sources under the CAA. In the event of an enforcement action for an exceedance of a 

SIP emission limit, a source can elect to assert any common law or statutory defenses that it 

determines is supported, based upon the facts and circumstances surrounding the alleged 

violation. Under section 113(b), courts have explicit authority to impose injunctive relief, issue 

compliance orders, assess monetary penalties or fees and impose any other appropriate relief. 

Under section 113(e), courts are required to consider the enumerated statutory factors when 

assessing monetary penalties, including “such other factors as justice may require.” For example, 

if the exceedance of the SIP emission limitation occurs due to a malfunction, that exceedance is a 

violation of the applicable emission limitation, but the source retains the ability to defend itself in 

an enforcement action and to oppose the imposition of particular remedies or to seek the 

reduction or elimination of monetary penalties, based on the specific facts and circumstances of 

the event. Thus, elimination of a SIP affirmative defense provision that purported to take away 

the statutory jurisdiction of the court to exercise its authority to impose remedies does not disarm 

sources in potential enforcement actions. Sources retain all of the equitable arguments they could 

previously have made under an affirmative defense provision; they must simply make such 

arguments to the reviewing court as envisioned by Congress in section 113(b) and section 

 

33 The EPA notes that only the state and the Agency have authority to seek criminal penalties for 

knowing and intentional violation of CAA requirements. The EPA has this explicit authority 

under section 113(c). 
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113(e). Congress vested the courts with the authority to judge how best to weigh the evidence in 

an enforcement action and determine appropriate remedies. 

Removal of such impermissible SIP affirmative defense provisions is necessary to 

preserve the enforcement structure of the CAA, to preserve the jurisdiction of courts to 

adjudicate questions of liability and remedies in judicial enforcement actions and to preserve the 

potential for enforcement by states, the EPA and other parties under the citizen suit provision as 

an effective deterrent to violations. In turn, this deterrent encourages sources to be properly 

designed, maintained and operated and, in the event of violation of SIP emission limitations, to 

take appropriate action to mitigate the impacts of the violation. In this way, as intended by the 

existing enforcement structure of the CAA, sources can mitigate the potential for enforcement 

actions against them and the remedies that courts may impose upon them in such enforcement 

actions, based upon the facts and circumstances of the event. 

D. Response to Comments Concerning Affirmative Defense Provisions in SIPs 

The EPA received numerous comments concerning the portion of the Agency’s proposed 

response to the Petition in the February 2013 proposal that addressed the question of whether 

affirmative defense provisions are consistent with CAA requirements for SIPs. As explained in 

the SNPR, those particular comments submitted on the original February 2013 proposal are no 

longer germane, given that the EPA has substantially revised its initial proposed action on the 

Petition and its basis, both with respect to the overarching issue of whether such provisions are 

valid in SIPs under the CAA and with respect to specific affirmative defense provisions in 

existing SIPs of particular states. Accordingly, as the EPA indicated in the SNPR, it considers 

those particular comments on the February 2013 proposal no longer relevant and has determined 

that it is not necessary to respond to them. Concerning affirmative defense provisions, the 
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appropriate focus of this rulemaking is on the comments that addressed the EPA’s revised 

proposal in the SNPR. 

With respect to the revised proposal concerning affirmative defense provisions in the 

SNPR, the EPA received numerous comments, some supportive and some critical of the 

Agency’s proposed action on the Petition as revised in the SNPR. Many of these comments 

raised conceptual issues and arguments concerning the EPA’s revised interpretation of the CAA 

with respect to affirmative defense provisions in SIPs in light of the NRDC v. EPA decision and 

concerning the EPA’s application of that interpretation to specific affirmative defense provisions 

discussed in the SNPR. For clarity and ease of discussion, the EPA is responding to these 

overarching comments grouped by issue. 

1. Comments that the EPA is misapplying the decision of the D.C. Circuit in NRDC v. EPA

to SIP provisions because the decision only applies to the Agency’s own regulations pursuant to 

CAA section 112. 

Comment: Many commenters stated that the EPA’s reliance on the D.C. Circuit’s 

decision in NRDC v. EPA is misplaced in the SNPR because the opinion is limited to disapproval 

of a Maximum Achievable Control Technology (MACT) standard’s affirmative defense for 

unavoidable malfunctions. The commenters noted that the NRDC v. EPA decision did not 

address the issue of affirmative defense provisions in SIPs. The commenters argued that the D.C. 

Circuit’s opinion only stands for the narrow proposition that the EPA may not include an 
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affirmative defense to civil penalties in a National Emission Standard for Hazardous Air 

Pollutants (NESHAP)34 under CAA section 112. 

One commenter noted that the EPA, in the SNPR, stated that the NRDC v. EPA decision 

did not turn on any factors specific to CAA section 112 as support for the EPA applying the 

decision to SIPs. However, the commenter argued that this fact is not probative because neither 

party raised any argument specific to CAA section 112 and it is reasonable for a court to limit its 

analysis to the arguments presented before it. 

One commenter also noted that the EPA is not bound to apply D.C. Circuit law to actions 

reviewable in other circuits. 

Response: As explained in the SNPR, the EPA believes the reasoning of the court in the 

NRDC v. EPA decision indicates that states, like the EPA, have no authority in SIP provisions to 

alter the jurisdiction of federal courts to assess penalties for violations of CAA requirements 

through affirmative defense provisions.35 If states lack authority under the CAA to alter the 

jurisdiction of the federal courts through affirmative defense provisions in SIPs, then the EPA 

lacks authority to approve any such provision in a SIP. 

 

34 The NESHAPs are found in 40 CFR part 61 and 40 CFR part 63. The NESHAPs promulgated 

after the 1990 CAA Amendments are found in 40 CFR part 63. These standards require 

application of technology-based emissions standards referred to as Maximum Achievable 

Control Technology (MACT). Consequently, these post-1990 NESHAPs are also referred to as 

MACT standards. 

35 See 79 FR 55929–30; 55931–34. 
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The EPA agrees with the commenters’ statement that the NRDC v. EPA decision 

pertained to a challenge to the EPA’s NESHAP regulations issued pursuant to CAA section 112 

to regulate hazardous air pollutants from sources that manufacture Portland cement. However, 

the EPA disagrees with the commenters’ contention that, because the NRDC v. EPA decision was 

based on a NESHAP, it is somehow inappropriate for the EPA to rely on the reasoning of the 

D.C. Circuit’s decision as a basis for this action. 

As acknowledged by a commenter, the EPA explained in the SNPR that the NRDC v. 

EPA decision did not turn on the specific provisions of CAA section 112.36 However, the 

commenter missed the import of this point. Although the NRDC v. EPA decision analyzed the 

legal validity of an affirmative defense provision created by the EPA in conjunction with a 

specific NESHAP, the court based its decision upon the provisions of sections 113 and 304. 

Sections 113 and 304 pertain to enforcement of the CAA requirements more broadly, including 

to enforcement of SIP requirements. The court addressed section 112 and not sections germane 

specifically to SIPs, as only that section was before it. The EPA has applied the NRDC court’s 

analysis to sections 113 and 304 with respect to SIPs and has concluded that the NRDC court’s 

analysis is the better reading of the statutory provisions. 

The affirmative defense provision in the Portland Cement NESHAP required the source 

to prove, by a preponderance of the evidence in an enforcement proceeding, that the source met 

specific criteria concerning the nature of the event. These specific criteria required to establish 

the affirmative defense in the Portland Cement NESHAP are functionally the same as the criteria 

that the EPA previously recommended to states for SIP provisions in the 1999 SSM Guidance 

 

36 SNPR, 79 FR 55919 at 55932. 
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and that the EPA repeated in the February 2013 proposal notice. Accordingly, the EPA believes 

that the opinion of the court in NRDC v. EPA has significant impacts on the Agency’s SSM 

Policy with respect to affirmative defense provisions. The reasoning by the NRDC court, as 

logically extended to SIP provisions, indicates that neither states nor the EPA have authority to 

alter either the rights of other parties to seek relief or the jurisdiction of federal courts to impose 

relief for violations of CAA requirements in SIPs. The EPA believes that the court’s decision in 

NRDC v. EPA compelled the Agency to reevaluate its interpretation of the CAA as described in 

the SNPR. 

The EPA also disagrees with commenters who suggested that a decision of the D.C. 

Circuit should have no bearing on actions that affect states in other Circuits. The CAA vests 

authority with the D.C. Circuit to review nationally applicable regulations and any action of 

nationwide scope or effect, so the EPA believes it is appropriate to apply the reasoning of the 

NRDC court, which interprets CAA sections 113 and 304, to determine the legality of affirmative 

defense provisions in this national action.37 

2. Comments that the EPA is misapplying the decision of the D.C. Circuit in NRDC v. EPA

to SIP provisions because the court did not address the legality of affirmative defense provisions 

in SIPs. 

Comment: Many commenters alleged that the EPA inappropriately relied on the D.C. 

Circuit’s decision in NRDC v. EPA in the SNPR because the court specifically stated that its 

decision did not address whether affirmative defense provisions in SIPs were appropriate. The 

commenters pointed to the second footnote in the decision, in which the court explicitly stated: 

 

37 CAA section 307(b)(1). 
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“We do not here confront the question whether an affirmative defense may be appropriate in a 

State Implementation Plan.”38 Accordingly, the commenters argued that the NRDC v. EPA

decision is “non-binding” with respect to SIP provisions. 

Response: The EPA disagrees that the footnote relied upon by commenters renders 

application of the legal interpretation of the NRDC court to SIP provisions improper. The EPA 

specifically acknowledged and discussed the footnote in the NRDC v. EPA decision in the SNPR. 

The EPA explained its view of the significance of the footnote: “footnote 2 in the opinion does 

not signify that the court intended to take any position with respect to the application of its 

interpretation of the CAA to SIP provisions, let alone to suggest that its interpretation would not 

apply more broadly.” As discussed in the SNPR in detail, the EPA believes the logic of the 

court’s decision in NRDC v. EPA regarding the interpretation of sections 113 and 304 concerning 

affirmative defenses does extend to SIP provisions. 

3. Comment that the EPA is inappropriately relying on the NRDC v. EPA decision because 

the D.C. Circuit’s decision was decided in error. 

Comment: One commenter alleged that the EPA’s reliance on the NRDC v. EPA decision 

is misplaced because the court in that decision mistakenly relied on section 304(a) when holding 

that the EPA cannot restrict the jurisdiction of the courts with affirmative defense provisions. 

The commenter alleged that Congress did not intend to give the judiciary “fully-unfettered 

discretion” in section 304(a) because such a reading cannot be squared with section 304(b), 

which provides that “[n]o action can be commenced ... if the Administrator or State has 

commenced and is diligently prosecuting a civil action in a court of the United States.” 

 

38 749 F.3d 1055, 1064, n.2. 
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Response: The EPA does not agree with the commenter’s premise that the NRDC court 

erred by not considering section 304(b) as well as section 304(a). As the court correctly 

reasoned, section 304(a) authorizes any person to bring an enforcement action for violations of 

emission limitations. Section 304(f) defines the term “emission limitation” for this purpose very 

broadly. Section 304(b) does not alter the rights of any person who has given proper notice to 

bring such an action under section 304(a), unless the EPA or the state is diligently prosecuting a 

civil action to require compliance. The fact that section 304(b) limits the ability of any person to 

bring an enforcement action (as opposed to intervening in such action) if the EPA or the state is 

pursuing enforcement has no bearing upon whether the EPA or a state could seek to alter or 

eliminate the jurisdiction of the courts to determine liability or to impose remedies for violations 

of SIP emission limitations in judicial enforcement. 

The EPA also does not believe that this rulemaking is the appropriate forum in which to 

challenge the court’s decision. If the commenter believes that the D.C. Circuit’s holding in 

NRDC v. EPA was in error for this reason, the commenter should have pursued possible remedy 

through the judicial system, for example by requesting that the D.C. Circuit grant rehearing en 

banc to reconsider the NRDC v. EPA decision. 

4. Comments that the court’s reasoning in the NRDC v. EPA decision does not apply to 

affirmative defenses in SIP provisions because if a source qualifies for an affirmative defense, 

then there has been no violation. 

Comment: Several commenters stated that the D.C. Circuit’s analysis in the NRDC v. 

EPA opinion is based on statutory language that indicates Congress intended the courts, not the 

EPA, to decide what constitutes an appropriate penalty once a violation has occurred. The 

commenters argued that if a SIP provision contains an affirmative defense, and if a source meets 
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the requirements to qualify for that affirmative defense, then there is no violation of the SIP 

requirements. One commenter contended that if there is no violation, then the courts have no 

jurisdiction to award any remedies and thus there can be no concern that the affirmative defense 

provision alters or eliminates the jurisdiction of the courts. Another commenter argued that 

affirmative defense provisions in the context of a SIP can be described as limitations on the 

application of an emission limitation to the conditions under which the emission reduction 

technology can be effectively operated. The commenters stated that the NRDC court did not 

address the EPA’s or states’ authority to establish requirements that determine, in the first 

instance, whether a violation has occurred. 

Response: The EPA disagrees with the commenters’ arguments that affirmative defense 

provisions are appropriate in SIPs if they merely define what constitutes a violation. As 

explained in detail in the SNPR, the EPA believes that SIP provisions with affirmative defenses 

that operate to limit or eliminate the jurisdiction of the courts to determine liability and to impose 

remedies are not consistent with CAA requirements. Under the commenters’ theory, such 

provisions would not improperly impinge on the jurisdiction of the courts to impose remedies for 

violations by redefining what constitutes a “violation.” 

First, the EPA does not agree that all affirmative defense provisions in the SIPs at issue in 

this action are constructed in this way. Some, including those that the EPA previously approved 

as consistent with the Agency’s 1999 SSM Guidance, explicitly provide that the excess 

emissions that occur are still violations, but a source could be excused from monetary penalties if 

the source met the criteria for the affirmative defense. Under the EPA’s prior interpretation of the 

CAA, the legal basis for any affirmative defense started with the fact that the excess emissions 

still constituted a violation and injunctive relief would still be available as appropriate. As 
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explained in the SNPR and this notice, the EPA no longer interprets the CAA to allow even 

narrowly drawn affirmative defense provisions in SIPs, let alone those advocated by the 

commenters that would provide a complete bar to any type of judicial remedy provided for in 

section 113(b). 

Second, even if a specific affirmative defense provision were worded in the way that the 

commenters’ claim, then that provision would be deficient for other reasons. Under the 

commenters’ premise, if certain criteria are met then there is no “violation” for excess emissions 

during SSM events. The EPA’s view is that this formulation of an affirmative defense in effect 

means that there is no emission limitation that applies when the criteria are met, i.e., the 

affirmative defense operates to create a conditional exemption for emissions from the source 

during SSM events. Such an approach would be inconsistent with the decision in Sierra Club v. 

Johnson concerning the term “emission limitation” in section 302(k). Exemptions for emissions 

during SSM events, whether automatic or conditional based upon the criteria of an affirmative 

defense, are inconsistent with the requirement for continuous controls on sources. 

Finally, the EPA believes that the commenters’ premise that an affirmative defense 

provision merely defines what a violation is also runs afoul of other fundamental requirements 

for SIP provisions. To the extent any such provision would allow state personnel to decide, 

unilaterally, whether excess emissions during an SSM event constitute a violation (e.g., through 

application of an “affirmative defense”), this would interfere with the ability of the EPA or other 

parties to enforce for violations of SIP requirements. The EPA interprets the CAA to prohibit SIP 

provisions that impose the enforcement discretion decisions of a state on other parties. This 

includes provisions that are structured or styled as an affirmative defense but in effect allow ad 
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hoc conditional exemptions from emission limitations and preclude enforcement for excess 

emission during SSM events. 

5. Comments that the NRDC v. EPA decision, which concerned an emission limitation 

under section 112, does not apply in the context of section 110, because section 110 affords 

states flexibility in how to develop emission limitations in SIP provisions. 

Comment: Commenters argued that the EPA’s extension of the logic of the NRDC v. EPA

decision to affirmative defenses in SIP provisions is incorrect because the EPA’s NESHAP 

standards are governed by section 112, whereas SIP provisions are governed by section 110. 

Under the latter, commenters asserted, states are afforded wide discretion in how to develop 

emission limitations.39 The commenters stated that section 110 governs the development of state 

SIPs to satisfy the NAAQS, which may address many different types of sources, major and 

minor, industrial and non-industrial, small and large, and old and new. The commenters alleged 

that states have independent authority to include affirmative defenses in SIP provisions, so long 

as the provisions are otherwise approvable, because the state has met its section 110 planning 

responsibilities and the SIP is enforceable. 

Response: The EPA agrees with the commenters that section 110 governs the 

development of state SIPs and that states are accorded great discretion in determining how to 

meet CAA requirements in SIPs. However, as explained in the February 2013 proposal, the 

SNPR and sections IV.D.13 and V.D.2 of this document, states are obligated to develop SIP 

provisions that meet fundamental CAA requirements. The EPA has the responsibility to review 

SIP provisions developed by states to ensure that they in fact meet fundamental CAA 

 

39 See, e.g., Train v. NRDC, 421 U.S. 60, 79 (1975). 
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requirements. As explained in the SNPR and this notice, the EPA no longer believes that 

affirmative defense provisions meet CAA requirements. Based on the logic of the court’s opinion 

in the NRDC v. EPA decision, the better reading of the statute is that such provisions have the 

effect of limiting or eliminating the statutory jurisdiction of the courts to determine liability or 

impose remedies. 

The EPA also disagrees with the commenters’ arguments that “emission limitations” 

under section 112 and section 110 are not comparable with respect to meeting fundamental CAA 

requirements. As an initial matter, both section 112 MACT standards and section 110 SIP 

emission limitations can be composed of various elements that include, among other things, 

numerical emission limitations, work practice standards and monitoring and recordkeeping 

requirements. However, whether or not there are other components that are part of the emission 

limitation to make it apply continuously is not relevant for purposes of determining whether an 

affirmative defense provision that provides relief from penalties for a violation of either a MACT 

standard under section 112 or a SIP provision under section 110 is consistent with the CAA. 

As explained in the SNPR, the EPA has revised its interpretation of the CAA with respect 

to affirmative defense provisions in SIPs, based upon the logic of the court in the NRDC v. EPA

decision. Section 304(a) sets forth the basis for a civil enforcement action and section 113(a)(1) 

does the same for administrative or judicial enforcement actions brought by the EPA. Sections 

113(b) and 304(a) provide the federal district courts with jurisdiction to hear civil enforcement 

cases. Furthermore, section 113(e) confers jurisdiction on the district court in a civil enforcement 

case to determine the amount of penalty to be assessed where a violation has been established. 

6. Comments that the NRDC v. EPA decision does not pertain to the appropriateness of 

affirmative defense provisions in the context of state administrative or civil enforcement. 
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Comment: Some commenters noted that the NRDC court only reviewed whether 

affirmative defense provisions could be used to limit CAA citizen suit remedies in judicial 

enforcement actions. The commenters alleged that the use of an affirmative defense in a citizen 

suit under federal regulations does not dictate the appropriateness of similar provisions in the 

context of state administrative or civil actions. According to the commenters, a SIP represents an 

air quality management system and the state administrative process is distinct from federal 

citizen suits. Similarly, the commenters believed that SIP emission limitations are enforceable 

via state regulation penalty provisions that are separate from the CAA civil penalty provisions. 

Because the NRDC court spoke only to the appropriateness of affirmative defense provisions in 

the context of federal citizen suits, the commenters asserted, the decision is inapplicable in the 

EPA’s SIP call action. 

Response: The EPA agrees that the court in the NRDC v. EPA decision did not speak 

directly to the issue of whether states can establish affirmative defenses to be used by sources 

exclusively in state administrative enforcement actions or in judicial enforcement in state courts. 

The reasoning of the NRDC court indicates only that such provisions would be inconsistent with 

the CAA in the context of judicial enforcement of SIP requirements in federal court. Indeed, the 

NRDC court suggested that if the EPA elected to consider factors comparable to the affirmative 

defense criteria in its own administrative enforcement proceedings, it may be able to do so. The 

implication of the commenters, however, is that the EPA should interpret the CAA to allow 

affirmative defenses in SIP provisions, so long as it is unequivocally clear that sources cannot 

assert the affirmative defenses in federal court enforcement actions and cannot assert the 

affirmative defenses in enforcement actions brought by any party other than the state. 
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The EPA of course agrees that states can exercise their own enforcement discretion and 

elect not to bring an enforcement action or seek certain remedies, using criteria analogous to an 

affirmative defense. It does not follow, however, that states can impose this enforcement 

discretion on other parties by adopting SIP provisions that would apply in federal judicial 

enforcement, or in enforcement brought by the EPA or other parties. To the extent that the state 

developed an “enforcement discretion” type provision that applied only in its own administrative 

enforcement actions or only with respect to enforcement actions brought by the state in state 

courts, such a provision may be appropriate. This authority is not unlimited because the state 

could not create affirmative defense provision that in effect undermines its legal authority to 

enforce SIP requirements. Section 110(a)(2)(C) requires states to have a program that provides 

for enforcement of the state’s SIP, and enforcement discretion provisions that unreasonably limit 

the state’s own authority to enforce the requirements of the SIP would be inconsistent with 

section 110(a)(2)(C). The EPA’s obligations with respect to SIPs include determining whether 

states have adequate enforcement authority. 

7. Comments that the EPA’s proposal is inappropriate because it runs counter to previous 

court decisions, including the decision of the U.S. Court of Appeals for the Fifth Circuit (Fifth 

Circuit) in Luminant Generation v. EPA. 

Comment: Many commenters on the SNPR argued that the decision of the Fifth Circuit in 

Luminant Generation v. EPA precludes the EPA’s proposed action concerning affirmative 

defenses in SIP provisions, in general and with respect to the provisions in the Texas SIP in 

particular. The commenters noted that the court upheld the EPA’s approval of an affirmative 

defense provision for unavoidable excess emissions during unplanned SSM events in the Texas 
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SIP.40 The commenters argued that the Fifth Circuit ruled that in approving the Texas SIP 

affirmative defense provision, the EPA “acted neither contrary to law nor in excess of its 

statutory authority.”41 According to the commenters, the court specifically considered and 

rejected arguments by litigants concerning sections 113 and 304. Some commenters argued that 

the court also considered and “decisively rejected” the legal arguments articulated by the EPA in 

the SNPR. The commenters alleged that the Luminant Generation v. EPA decision demonstrates 

that affirmative defenses for malfunctions are permissible in SIP provisions. The commenters 

contended that, because the Fifth Circuit in Luminant Generation v. EPA specifically considered 

whether an affirmative defense provision applicable to malfunctions included in a SIP violates 

the CAA, unlike the D.C. Circuit in NRDC v. EPA, the EPA should follow the Luminant 

Generation v. EPA decision rather than the D.C. Circuit decision in NRDC v. EPA. 

Some commenters also pointed out that the D.C. Circuit, in the recent NRDC v. EPA

decision, mentioned and cited the Luminant Generation v. EPA opinion and did not expressly 

disagree with the Fifth Circuit’s holding. One commenter noted that if the NRDC court believed 

that the issue it was deciding was the same as the issue decided in Luminant Generation v. EPA, 

the D.C. Circuit would have explicitly stated that it was declining to follow the Fifth Circuit on 

the issue instead of acknowledging that the issue upon which the Fifth Circuit ruled was not 

before the D.C. Circuit. 

Several commenters also argued that, because the Fifth Circuit previously determined in 

Luminant Generation v. EPA that the Texas SIP affirmative defense provision at issue in this SIP 

 

40 714 F.3d 841 (5th Cir. 2013). 

41 Id. at 853. The EPA notes that the Fifth Circuit also upheld the Agency’s disapproval of the 

affirmative defense provisions that the state sought to create for “planned” events. 
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call action is consistent with CAA sections 113 and 304, the EPA does not have any legal 

authority under the CAA to finalize the action proposed in SNPR. Some commenters further 

stated that the EPA lacks authority to disagree with the Fifth Circuit’s determination of the law 

as applied to a state within the Fifth Circuit’s jurisdiction. These commenters believed that if the 

EPA were to finalize the action discussed in the SNPR with respect to the affirmative defense for 

malfunctions in the Texas SIP, this action would violate the mandate rule. Some commenters 

also alleged that courts outside the Fifth Circuit, including the D.C. Circuit, will apply principles 

of claim preclusion, or res judicata, to give effect to the Fifth Circuit’s prior adjudication on the 

legal basis for the affirmative defense in the Texas SIP. One commenter claimed that the EPA’s 

“failure” to address how the holdings in Luminant Generation v. EPA will no longer apply and 

how the EPA is exempt from the court’s mandate render the theories presented in the SNPR 

unsupported as a basis for the SIP call action. 

Some commenters alleged that the EPA is bound by its own prior representations before 

the Fifth Circuit, in which it asserted and defended its approval of the affirmative defense 

provision for malfunctions in the Texas SIP, under the doctrine of judicial estoppel.42 Similarly, 

the commenters alleged that under the doctrine of issue preclusion, or collateral estoppel, the 

EPA is precluded from re-litigating the issues previously considered and determined by the Fifth 

Circuit, regardless of where any subsequent challenge to this final action is brought. 

Some commenters also cited to other Circuit opinions that have upheld the EPA’s 

approvals of affirmative defense provisions for malfunctions.43 The commenters alleged that 

 

42 See, e.g., New Hampshire v. Maine, 532 U.S. 742, 749 (2001). 

43 See Montana Sulphur & Chemical Co. v. EPA, 666 F.3d 1174 (9th Cir. 2012); Arizona Public 

Service Co. v. EPA, 562 F.3d 1116 (10th Cir. 2009). 
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other than calling the NRDC v. EPA decision a newer decision, the EPA did not explain its 

justification for relying on the NRDC v. EPA opinion instead of following the three circuit court 

decisions that are directly on point. 

Response: The EPA disagrees with the commenters’ arguments concerning the 

application of the court’s decision in Luminant Generation v. EPA to this SIP call action. As 

explained in the SNPR, the EPA acknowledges that it has previously approved affirmative 

defenses in SIP provisions or, when appropriate, promulgated affirmative defenses in FIPs. The 

EPA also acknowledged that its approval of an affirmative defense provision applicable to 

“unplanned events” (i.e., malfunctions) in a Texas SIP submission was upheld in 2012 by the 

U.S. Court of Appeals for the Fifth Circuit. In that litigation, the EPA argued that sections 113 

and 304 do not preclude appropriately drawn affirmative defense provisions for malfunctions in 

SIPs. Importantly, in upholding the EPA’s approval of the affirmative defense, the Fifth Circuit 

determined that Chevron step 1 was not applicable to this case and “turn[ed] to step two of 

Chevron”44 in holding that the Agency’s interpretation of the CAA at that time was a 

“permissible interpretation of section [113], warranting deference.”45 The Fifth Circuit did not 

determine that the EPA’s interpretation at the time of the Luminant Generation v. EPA decision 

was the only or even the best permissible interpretation. It is clearly within the EPA’s legal 

authority to now revise its interpretation to a different, but still permissible, interpretation of the 

 

44 714 F.3d at 852. 

45 Id. at 853. 
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statute.46 The EPA has explained at length in the SNPR, and elsewhere in this final rulemaking, 

its reasons for changing its previous interpretation of the CAA to permit narrowly drawn 

affirmative defenses applicable only to penalties and has explained why it now believes that the 

reasoning of the court in the NRDC v. EPA decision is the better reading of the CAA. 

Some commenters allege that the Fifth Circuit considered and rejected the legal 

arguments articulated by the EPA in the SNPR to support the Agency’s new interpretation that 

affirmative defenses in SIP provisions are inconsistent with the Act. The EPA disagrees with 

commenters’ assertions. As explained above, in the Luminant Generation v. EPA decision the 

Fifth Circuit analyzed the EPA’s former interpretation of the CAA under step 2 of Chevron and 

found that the Agency’s position was reasonable. The Fifth Circuit held that the CAA did not 

dictate the outcome put forth by environmental petitioners in the Luminant Generation v EPA

case; the court did not hold that the Agency could not reasonably interpret the CAA provisions at 

issue to come to the new position articulated in the SNPR and other sections of this notice. In 

fact, the Fifth Circuit upheld the EPA’s reading of the statute to preclude affirmative defense 

provisions for planned events in the same decision as a reasonable interpretation of the CAA. 

In the SNPR, the EPA also addressed the discussion in the NRDC v. EPA decision that 

referred to the earlier Luminant Generation v. EPA decision and explained its view that the court 

 

46 See, e.g., Nat’l Cable & Telecomms. Ass’n v. Brand X Internet Servs., 545 U.S. 967 (2005) and 

FCC v. Fox Television Stations, Inc., 556 U.S. 502 (2009). The Agency also notes that 

commenters’ position, that the EPA cannot now change its interpretation of the CAA, is at odds 

with the SIP call provision established by Congress in section 110(k)(5). That provision provides 

the EPA with authority to issue a SIP call “whenever” it determines that an existing SIP is 

substantially inadequate to meet CAA requirements. In other words, section 110(k)(5) expressly 

envisions cases where the EPA has previously approved a SIP provision as meeting CAA 

requirements, and one that the EPA may have even defended in court, but later determines that 

the provision no longer meets CAA requirements, and section 110(k)(5) gives the EPA authority 

to issue a SIP call in these situations. 
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in NRDC v. EPA did not suggest that its interpretation of the CAA would not apply more broadly 

to SIP provisions. It simply declined to address that issue. As to commenters’ allegation that the 

EPA should follow the Luminant court’s reasoning because that court addressed the specific 

issue of affirmative defenses in SIP provisions, the EPA explained in detail in the SNPR and in 

section IV.D.1 of this notice why it now believes that the NRDC court’s reasoning is applicable 

here and why it believes this is the better interpretation of sections 113 and 304. 

The EPA acknowledges that other Circuits have also upheld affirmative defense 

provisions promulgated by the Agency in FIPs.47 Those decisions were also based upon an 

interpretation of the CAA that the Agency no longer holds. The EPA further notes that the 

affirmative provisions at issue in the other Circuit opinions cited by the commenters are not at 

issue in this action. However, the EPA may elect to address these provisions in a separate 

rulemaking.

The EPA also disagrees with commenters’ allegations that this final SIP call action 

violates the mandate rule. The mandate rule generally governs how a lower court handles a 

higher court’s decision on remand. The Agency believes that the mandate rule is inapplicable 

here. Similarly, the Agency believes that the principles of res judicata, judicial estoppel and 

collateral estoppel (issue preclusion) raised by commenters are all inapplicable in this situation. 

For reasons the EPA has fully explained in this rulemaking, the Agency is adopting a revised 

interpretation of the CAA. This necessarily changes the issues or claims that may be raised in 

any future litigation concerning the Agency’s action here or subsequent Agency actions taken 

pursuant to this changed interpretation. As noted previously, the Agency’s ability to change its 

 

47 See Montana Sulphur & Chemical Co. v. EPA, 666 F.3d 1174 (9th Cir. 2012); Arizona Public 

Service Co. v. EPA, 562 F.3d 1116 (10th Cir. 2009). 
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interpretation of the statute is well established, even if courts have previously upheld the 

Agency’s former interpretation as reasonable under step 2 of the Chevron analysis. 

8. Comments that affirmative defense provisions are needed or appropriate because sources 

cannot control malfunctions or the excess emissions that occur during them. 

Comment: Several commenters claimed that by requiring states to remove affirmative 

defense provisions, the EPA will create a situation where sources have no potential relief from 

liability for exceedances resulting from excess emissions during malfunctions. The commenters 

argued that this will effectively expose sources to penalties for emissions that are not within the 

sources’ control. The commenters alleged that the EPA’s proposal is unreasonable because it 

fails to consider the infeasibility of controlling emissions during malfunction periods. The 

commenters believe that because malfunction events are uncontrollable by definition, removing 

affirmative defense provisions applicable to malfunctions will not reduce emissions but instead 

will only expose facilities to potential enforcement for uncontrollable exceedances. 

Response: The EPA disagrees that without affirmative defense provisions, sources will 

have no “relief” from liability for violations during actual malfunctions. To the extent that 

sources have an actual malfunction, sources retain the ability to raise this fact in the event of an 

enforcement action related to the malfunction. Congress has already provided courts with 

explicit jurisdiction and authority to determined liability and to impose appropriate remedies, 

based on the facts and circumstances surrounding the violation. To the extent that there are 

extenuating circumstances that justify not holding a source responsible for a violation or 

imposing particular remedies as a result of a violation, sources retain the ability to raise these 

facts to the court. In addition, the absence of an affirmative defense provision in the SIP does not 

impede a violating source from taking appropriate actions to minimize emissions during a 
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malfunction, so as to mitigate the potential remedies that a court may impose as a result of the 

violation. 

Furthermore, the EPA disagrees with the commenters’ premise that states have authority 

to create affirmative defense provisions in SIPs because some sources may otherwise be subject 

to enforcement actions for emissions during malfunctions. As explained in the SNPR in detail, 

the EPA has concluded that there is no legal basis for affirmative defenses in SIP provisions, 

including affirmative defenses applicable to malfunction events. Because such affirmative 

defense provisions purport to alter or eliminate the statutory jurisdiction of courts to determine 

liability and to assess appropriate remedies for violations of SIP requirements, these provisions 

are not permissible. 

9. Comments that there will not be any reduction in overall emissions from the EPA’s SIP 

call action because states will need to revise emission limitations to allow more emissions if 

affirmative defense provisions are removed from the SIPs. 

Comment: Commenters on the SNPR questioned whether the elimination of affirmative 

defenses in SIP provisions would result in any reductions of emissions from sources. Several 

commenters asserted that affirmative defense provisions allow states to lower emission 

limitations overall. Thus, the commenters claimed that elimination of the affirmative defense 

provisions would obligate states to raise affected emission limitations so that sources could 

comply with them continuously. Another commenter criticized the EPA’s approach as requiring 

each state to reframe the existing episodic emissions provisions of its SIP as alternative emission 

limitations, rather than as more limited and conditional affirmative defenses. This commenter 

asserted that structuring the provisions as an affirmative defense allows a state to impose more 
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stringent numerical limitations without penalizing sources for unavoidable emissions when those 

emissions do not compromise the underlying air quality objectives. 

Several commenters also disagreed with the EPA’s belief that removal of affirmative 

defense provisions would reduce emissions. One commenter noted that some affirmative defense 

provisions require a source to evaluate impacts on NAAQS compliance as part of asserting the 

affirmative defense; the commenter contended that forgoing these provisions would thus reduce 

the incentive for owners and operators to minimize emissions during malfunctions so that they 

could qualify for the affirmative defense. Several commenters noted that many sources 

immediately investigate excess emissions events and implement measures intended to prevent 

recurrence. Nevertheless, those commenters asserted that because malfunction events are 

uncontrollable by definition, removing an affirmative defense applicable to malfunctions will not 

reduce emissions. Commenters also argued that an assumption that elimination of the affirmative 

defense provisions will reduce emissions is flawed because, given the stringent applicability 

criteria for a “narrowly drawn” affirmative defense, a facility has no assurance that an 

affirmative defense will apply to any particular malfunction event and that even if the affirmative 

defense was available, it would not shield the facility from compliance orders or other injunctive 

relief (or from criminal prosecution). 

Response: The commenters’ arguments concerning whether elimination of affirmative 

defense provisions will or will not reduce emissions during SSM events and will or will not 

reduce incentives for sources to minimize emissions during SSM events do not address the legal 

basis for any such affirmative defense provisions. As the commenters correctly observed, the 

EPA’s 1999 SSM Guidance reflected the Agency’s prior interpretation of the CAA to permit 

such affirmative defense provisions, so long as they were sufficiently narrowly drawn, applied 
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only to monetary penalties and required the source to prove that it met the applicable criteria to 

the trier of fact in an enforcement proceeding. The EPA’s arguments for why appropriate 

affirmative defense provisions could be consistent with CAA requirements included that they 

could provide an incentive for sources to be properly designed, maintained and operated to 

minimize emissions at all times. 

As explained in the SNPR, however, the EPA has determined that affirmative defenses 

are impermissible in SIP provisions because they operate to alter or eliminate the statutory 

jurisdiction of the courts. The EPA has reached this conclusion in light of the court’s decision in 

NRDC v. EPA. Because affirmative defense provisions are inconsistent with the enforcement 

structure of the CAA, the EPA is making the finding that such provisions are substantially 

inadequate to meet legal requirements of the CAA. In order to make the finding that these 

provisions fail to meet legal requirements of the CAA, the EPA is not required to determine or 

estimate emission reductions that will or will not result from the removal of such provisions from 

the affected SIPs. The EPA’s obligation would not change even if commenters were correct in 

their view that emissions reductions will not result from the removal of the impermissible 

affirmative defense provisions. The EPA’s interpretation of its authority under section 110(k)(5) 

is discussed in detail in section VIII.A of this notice. 

The EPA agrees that in response to this SIP call directing the removal of affirmative 

defense provisions, the affected states may elect to revise affected SIP emission limitation. In so 

doing, the states may determine that it is appropriate to revise the emission limitations in other 

respects, so long as they do so consistent with CAA requirements. For example, affected states 

may elect to create alternative emission limitations that apply to sources during startup and 

shutdown. The EPA’s guidance for this approach is discussed in detail in VII.B.2 of this 
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document. Alternatively, states may elect to overhaul an affected SIP emission limitation entirely 

to account for the removal of the affirmative defense in some other way. However, states will 

need to comply with the applicable substantive requirements for the type of SIP provision at 

issue and the EPA will review those SIP revisions in accordance with the requirements of the 

CAA, including section 110(k)(3), section 110(l) and section 193. 

10. Comments that the elimination of affirmative defense provisions will result in sources’ 

facing inconsistent treatment by courts or states when excess emissions are emitted during 

malfunction events. 

Comment: Commenters claimed that the concept and framework for affirmative defense 

provisions are consistent from state to state and that by removing these provisions, sources will 

be subject to inconsistent treatment of excess emissions during SSM in different states. The 

commenters noted that the EPA recognized in the February 2013 proposal and SNPR that states 

may elect to revise their deficient SIP provisions differently in response to the SIP call and thus 

the commenters expressed concern that the potential difference in treatment among states will 

lead to “inconsistent regulation of air pollution across the country.” 

Commenters further argued that without the consistent regulatory framework provided by 

an affirmative defense provision, each court is likely to evaluate SSM events differently in the 

context of enforcement actions. The commenters suggested that allowing each court to consider 

the facts and circumstances of the emission event in its penalty evaluation without a governing 

framework could lead to inconsistent enforcement throughout the country. 

Response: The EPA disagrees that it is inappropriate to allow states to determine how 

best to revise their SIPs in response to this SIP call, consistent with CAA requirements. As 

discussed in this document, and as many commenters have also noted, the structure of the CAA 
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is based upon cooperative federalism. Under this structure, Congress gave states broad discretion 

to develop SIP provisions as necessary to attain and maintain the NAAQS and meet other CAA 

objectives, so long as the SIPs also meet statutory requirements. The very nature of the SIP 

program is that similar sources can be treated differently in different states, because the states 

have discretion with respect to developing their SIP provisions consistent with CAA 

requirements. Thus, whether or not the affirmative defense provisions at issue in this action 

added some level of “consistent” treatment of sources across the nation (a statement with which 

the EPA does not agree) is not relevant for purposes of this SIP call.48 Rather, for the reasons 

explained in the SNPR and in this notice, the EPA has determined that affirmative defense 

provisions are inconsistent with the fundamental legal requirements of the CAA. For that reason, 

the EPA is requiring the affected states to revise their SIPs to remove the affirmative defense 

provisions identified in this action. States have discretion in how they revise their SIPs in this 

context as in all other contexts. 

As to the concern that different courts might evaluate liability for violations during SSM 

events differently in the absence of affirmative defense provisions, the EPA notes that this is not 

the relevant question. The potential for inconsistent treatment by the courts is not a basis for 

allowing states to retain SIP provisions that are inconsistent with the legal requirements of the 

CAA. In any event, the EPA disagrees that elimination of affirmative defenses in SIP provisions 

make it more likely that there would be “inconsistent enforcement” because of a lack of a 

 

48 The EPA notes that the actual affirmative defense provisions at issue in this action are very 

dissimilar; some are based on the EPA’s interpretation of the CAA in the 1999 SSM Guidance, 

but the majority of the provisions are relatively unique from state to state. Accordingly, the EPA 

disagrees with the commenters’ basic premise that the affirmative defense provisions are 

consistent from state to state. 
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“regulatory framework.” The enforcement structure of the CAA embodied in section 113 and 

section 304 already provides a structure for enforcement of CAA requirements in federal courts. 

For example, the CAA already provides uniform criteria for courts to apply, based upon the facts 

and circumstances of individual enforcement actions. Similar to an affirmative defense 

provision, section 113(e) already enumerates the factors that courts are required to consider in 

determining appropriate penalties for violations and thus there is a consistent statutory 

framework. In essence the commenters object to the fact that in any judicial enforcement case, 

the court will determine liability and remedies based on the facts and circumstances of the case. 

However, this is an inherent feature of the enforcement structure of the CAA, regardless of 

whether there is an affirmative defense provision at issue. 

11. Comments that the EPA should have acted in a single, comprehensive rulemaking rather 

than issuing the supplemental notice of proposed rulemaking. 

Comment: Commenters asserted that the EPA’s issuance of two separate proposals 

instead of one proposal has prevented states and industry from knowing the entire proposed 

regulatory action. The commenters claimed that if the EPA is going to issue a SIP call to states 

concerning the treatment of emissions during SSM events, then it should do so in a single 

comprehensive rulemaking. The commenters argued this is necessary because states consider 

different options when revising SIP provisions and that thereafter states will have to work with 

affected sources to revise permits. 

Response: The EPA disagrees with the argument that states, industry, individuals and 

other interested parties have not had an opportunity to know and comment upon the Agency’s 

entire action. The EPA’s February 2013 proposal was intended to cover a broad range of issues 

related to the correct treatment of emissions during SSM events in SIP provisions 
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comprehensively. Because of an intervening court decision that affected the substance of the 

EPA’s initial proposed action, it was necessary to issue a supplemental proposal. The EPA 

disagrees that the issuance of the SNPR adversely affected the ability of interested parties to 

understand the Agency’s proposed action, because the SNPR only affected one aspect of the 

original proposed action. As the EPA explained in the SNPR: “In this SNPR, we are 

supplementing and revising what we earlier proposed as a response to the Petitioner’s requests 

but only to the extent the requests narrowly concern affirmative defense provisions in the SIPs. 

We are not revising or seeking further comment on any other aspects of the February 2013 

proposed action.”49 

As to the commenters’ concern that the EPA should take action in a single 

comprehensive rulemaking, the Agency is doing so. This SIP call action addresses all aspects of 

the Petition and it is based upon both the February 2013 proposal and the SNPR. As advocated 

by the commenters, the EPA’s objective in this SIP call action is to provide states with 

comprehensive and up to date guidance concerning the correct treatment of emissions during 

SSM events in SIP provisions, consistent with CAA requirements as interpreted by recent court 

decisions. The EPA agrees with the commenters that providing states comprehensive guidance in 

this rulemaking is important to assist states in revising their SIP provisions consistent with CAA 

requirements. Any necessary changes to permits to reflect the removal of affirmative defense 

provisions from the underlying SIP will occur later, after the SIP provisions have been revised. 

 

49 79 FR 55919 at 55923. 
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12. Comments that the EPA has not proven that the existence of affirmative defense 

provisions in SIPs is resulting in specific environmental impacts or interference with attainment 

and maintenance of the NAAQS. 

Comment: Several commenters argued that the EPA has failed to demonstrate that the 

affirmative defense provisions at issue in this action have contributed to a specific NAAQS 

violation or otherwise caused harm to public health or the environment. The commenters contend 

that, because of the narrow scope of affirmative defense provisions, it is unlikely that their 

existence would cause or contribute to any violations of the NAAQS. Some commenters further 

noted that some states have experienced improved ambient air quality conditions, despite having 

SIPs in place with affirmative defense provisions at issue in this action. 

The commenters alleged that without providing specific record-based evidence of the 

impacts caused by affirmative defense provisions, it is unreasonable for the EPA to determine 

that existing provisions are substantially inadequate or otherwise not in compliance with the 

CAA. Some commenters further alleged that the EPA has no authority to issue a SIP call without 

“find[ing] that the applicable implementation plan ... is substantially inadequate to attain or 

maintain the relevant [NAAQS].” 

Response: As explained in the February 2013 proposal, the SNPR and this notice, the 

EPA does not interpret its authority under section 110(k)(5) to require proof that a deficient SIP 

provision caused a specific violation of the NAAQS at a particular monitor on a particular date, 

or that a deficient SIP provision undermined a specific enforcement action. Section 110(k)(5) 

explicitly authorizes the EPA to make a finding that a SIP provision is substantially inadequate 

to “comply with any requirement of” the CAA, in addition to the authority to do so where a SIP 

is inadequate to attain and maintain the NAAQS or to address interstate transport. In light of the 
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court’s decision in NRDC v. EPA, the EPA has reexamined the question of whether affirmative 

defenses are consistent with CAA requirements for SIP provisions. As explained in this action, 

the EPA has concluded that such provisions are inconsistent with the requirements of section 113 

and section 304. Accordingly, the EPA has the authority to issue SIP calls to states, requiring 

that they revise their SIPs to eliminate the specific affirmative defense provisions identified in 

this action. Issues related to the EPA’s authority under section 110(k)(5) are discussed in more 

detail in section VIII.A of this document. 

13. Comments that the EPA is violating the principles of cooperative federalism through this 

action. 

Comment: Several commenters stated that the EPA’s action with respect to affirmative 

defenses in SIP provisions is inconsistent with the system of cooperative federalism 

contemplated by the CAA. The commenters alleged that this action is at odds with established 

CAA and judicial precedent that states have broad discretion in developing SIP provisions, with 

the EPA’s role being limited. Some commenters further alleged that the EPA’s action has the 

effect of unlawfully directing states to impose a particular control measure. The commenters 

argued that the EPA must defer to a state’s choice on how to meet the relevant NAAQS, through 

whatever SIP provisions they elect to develop. One commenter argued that states have 

independent authority to include affirmative defense policies in their SIPs, even if the D.C. 

Circuit has held that the EPA may not include affirmative defense provisions in federal 

regulations. 

Response: The EPA agrees that the CAA is based upon the principle of cooperative 

federalism but disagrees with the commenters’ characterization of the respective authorities and 

responsibilities of states and the Agency. As explained in the February 2013 proposal, and in 
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section V.D.2 of this notice, the EPA has the authority and the obligation to ensure that SIP 

provisions meet fundamental CAA requirements, when initially submitted and later. In the case 

of affirmative defenses in SIP provisions, the EPA has determined that such provisions do not 

comply with CAA requirements because they operate to alter or eliminate the statutory 

jurisdiction of the courts, contrary to section 113 and section 304. The states have broad 

discretion to create SIP provisions but must do so consistent with CAA requirements. By issuing 

this SIP call, the EPA is not in any way compelling states to impose any specific SIP control 

measure on any specific source but merely requiring states to revise their SIP provisions to make 

them consistent with CAA requirements. 

14. Comments that the EPA failed to account adequately for the amount of time and 

resources that will be required to revise state SIPs. 

Comment: Many commenters asserted that the EPA’s SNPR did not address or recognize 

that removal of affirmative defense provisions from SIPs will impose enormous burdens on 

states because they will need to revise SIPs to create alternative emission limitations in lieu of 

the affirmative defenses. Commenters contended that removal of the affirmative defense 

provisions will necessarily require state air pollution control agencies to make extensive 

revisions to SIPs and that in many states, such changes will have to be reviewed by the state 

legislature. Commenters explained that such an effort could not reasonably be completed in 

many states within the 18 months the EPA proposed to provide for SIP revisions in response to 

the final SIP call. Commenters also stated that the SSM provisions that the EPA proposed to 

require states to remove from their SIPs have been incorporated into thousands of title V 

operating permits and that those title V permits would, in turn, need to be modified if the 
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affirmative defense provisions are removed from the approved SIPs. Commenters indicated that 

states might also need to amend an even larger number of minor source permits. 

Commenters also indicated that in conjunction with removal of affirmative defenses, 

states will also have to reevaluate the emission limitations currently contained in their SIPs to 

determine if those limitations are still are consistent with federal and state law (e.g., represent 

reasonably available control technology). Some commenters expressed the view that the EPA 

must indicate that states will not be required to remove the identified affirmative defense 

provisions from their SIPs until the state has had time to consider whether emission limitations in 

state regulations and in construction and operating permits need to be modified and to obtain any 

necessary EPA approval for the modified requirements. Commenters also argued that the EPA’s 

suggestion that states subject to a SIP call could simply remove an existing affirmative defense 

provision and rely on enforcement discretion to address “unavoidable” exceedances is wrong and 

that states adopt emission limitations under state administrative rules that require the agency to 

provide a record to support the level of the emission limitation. 

Response: The EPA disagrees that it did not acknowledge that correction of the deficient 

SIP provisions at issue in this action will take time and resources. For this reason, the EPA is 

providing states with the maximum 18 months permitted by section 110(k)(5) to respond to this 

SIP call. In addition, the EPA is endeavoring to provide states with clear and comprehensive 

guidance concerning the proper treatment of excess emissions during SSM events in SIP 

provisions in order to make this process more efficient. 

The EPA acknowledges that some states, in conjunction with removal of affirmative 

defense provisions, may elect to undertake a more comprehensive revision of affected SIP 

emission limitations. In so doing, the states may need to undertake a more resource intensive 
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approach than those states that merely elect to eliminate the affirmative defense provisions. In 

addition, the EPA also recognizes that states may eventually need to revise permits to reflect the 

elimination of affirmative defense provisions from underlying SIP provisions that may have been 

reflected in permits. The EPA discussed these issues in the both the February 2013 proposal and 

in the SNPR. 

Despite the potential burden on states, as the EPA explained in the February 2013 

proposal and the SNPR, the Agency believes that it is obligated and authorized to issue this SIP 

call action to affected states to require the removal of affirmative defense provisions. The EPA is 

not in this action evaluating or determining whether SIP emission limitations should or should 

not be revised in light of the removal of affirmative defenses and is not required to do so. The 

states have discretion to determine how best to revise the deficient SIP provisions identified in 

this action, so long as they do so consistent with the CAA requirements. 

Further, the EPA does not agree that enforcement discretion cannot substitute for an 

affirmative defense for malfunctions. For example, the EPA has taken the position that the CAA 

does not require malfunction emissions to be factored into development of section 112 or section 

111 standards and that case-by-case enforcement discretion provides sufficient flexibility.50

Moreover, the EPA believes that Congress has already provided for such flexibility in section 

113, by providing the courts with jurisdiction to determine liability and to impose remedies. For 

example, in section 113(e), Congress provided specific criteria for courts to consider in imposing 

monetary penalties, includes consideration of such factors as justice may require. 

 

50 See, e.g., “Oil and Natural Gas Sector: Reconsideration of Additional Provisions of New 

Source Performance Standards; Proposed rule,” 79 FR 41752 at 41762–63 (July 17, 2014). 
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With respect to the potential need to amend permits, as explained in the February 2013 

proposal, “the EPA does not intend its action on the Petition to affect existing permit terms or 

conditions regarding excess emissions during SSM events that reflect previously approved SIP 

provisions....[A]ny needed revisions to existing permits will be accomplished in the ordinary 

course as the state issues new permits or reviews and revises existing permits. The EPA does not 

intend the issuance of a SIP call to have automatic impacts on the terms of any existing 

permit.”51 Thus, these permit revisions that commenters expressed concern about need not occur 

during the 18 month SIP development timeframe but may proceed thereafter according to normal 

permit revision requirements. 

Finally, the EPA notes the burdens associated with SIP revisions and permit revisions are 

burdens imposed by the CAA. The states have both the authority and the responsibility under the 

CAA to have SIPs and permit programs that meet CAA requirements. It is inherent in the 

structure of the CAA that states thus have the burden to revise their SIPs and permits when that 

is necessary, whether because of changes in the CAA, changes in judicial interpretations of the 

CAA, changes in the NAAQS, or a host of other potential events that necessitate such revisions. 

Among those is the obligation to respond to a SIP call that identifies legal deficiencies in specific 

provisions in a state’s SIP. 

15. Comments that the EPA is being inconsistent because rules promulgated by the EPA 

provide affirmative defense provisions for malfunction events. 

Comment: A number of commenters claimed that the EPA cannot interpret the CAA to 

prohibit affirmative defenses in SIP provisions because the Agency itself has issued regulations 

 

51 See February 2013 proposal, 78 FR 12459 at 12482 (February 22, 2013). 
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that include affirmative defenses for excess emissions during malfunction events. The 

commenters claim that the EPA is being inconsistent on this point and thus cannot require states 

to remove affirmative defenses from SIPs. 

Other commenters alleged that the EPA is being inconsistent because it has not 

adequately explained the reversal of its “decades-old” policy interpreting the CAA to allow 

affirmative defenses in SIP provision. The commenters cited to SIP provisions that the EPA 

previously approved in eight states between 2001 and 2010 that they believed would be affected 

by this SIP call. The commenters claimed that these prior actions were consistent with the EPA’s 

SSM policy memoranda. Additionally, the commenters cited to federal regulations that the EPA 

has previously promulgated that include affirmative defense provisions. The commenters 

claimed that these prior actions are “inconsistent with EPA’s proposed disallowance of 

affirmative defenses.” 

Response: The EPA has acknowledged that it has previously approved some SIP 

provisions with affirmative defenses that were consistent with its interpretation of the CAA in 

the 1999 SSM Guidance at the time it acted on those SIP submissions. However, since that time, 

two decisions from the D.C. Circuit have addressed fundamental interpretations of the CAA 

related to the legally permissible approaches for addressing excess emissions during SSM events. 

In light of those decisions, as explained in detail in the February 2013 proposal, the SNPR and 

this notice, the EPA has concluded that certain aspects of its prior interpretation of the CAA, as 

set forth in the SSM Policy, were not the best interpretation of the CAA. As a result, certain SIP 

provisions that the EPA previously approved are also not consistent with the requirements of the 

CAA. In particular, this includes the EPA’s prior interpretation of the CAA to allow affirmative 

defense provisions in SIPs in the 1999 SSM Guidance. 
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The EPA has also acknowledged that it has in the past taken a similar approach regarding 

affirmative defense provisions in federal regulations addressing hazardous air pollution and in 

new source performance standards. Indeed, the EPA’s inclusion of an affirmative defense 

provision in a federal regulation resulted in the court decision in NRDC v. EPA, in which the 

court rejected the Agency’s interpretation of the CAA to allow affirmative defenses that limit or 

eliminate the jurisdiction of the courts. Just as the EPA is calling on states to revise their SIPs to 

remove affirmative defense provisions, the Agency is also taking action to correct such 

provisions in federal regulations.52 The continued existence of such provisions in the EPA 

regulations that have not yet been corrected does not mean that such provisions are authorized 

either in state or federal regulations. 

As to the claim that the EPA has not explained the basis for changing its interpretation of 

the CAA regarding affirmative defenses in SIP provisions, the Agency disagrees. The SNPR set 

forth in detail the basis for the EPA’s revised interpretation of the CAA, in light of the court’s 

decision in NRDC v. EPA.

53 The commenters failed to specify why this explanation was 

“inadequate.” 

16. Comments that existing affirmative defense provisions do not preclude parties from filing 

enforcement actions or hinder parties from seeking injunctive relief for violations of SIP 

requirements. 

Comment: One state commenter asserted that the existing affirmative defense provisions 

in the state’s SIP do not prevent the state or the EPA from pursuing injunctive relief or 

mitigation of environmental impacts in the event of violations. Thus, the commenter supported 

 

52 See, e.g., 79 FR 60893 (October 8, 2014); 79 FR 72914 (December 8, 2014). 

53 79 FR 55919 at 55929–30. 
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the EPA’s prior interpretation of the CAA to allow affirmative defense provisions, so long as 

courts can still award injunctive relief for violations. The commenter did not articulate how this 

prior statutory interpretation is consistent with the reasoning of the court in NRDC v. EPA

concerning the same statutory provisions. 

By contrast, an environmental group commenter cited a citizen suit enforcement case in 

Texas in which the commenter claimed that the affirmative defense provision in that state’s SIP 

operated as a de facto shield against any enforcement. The commenter stated that the EPA’s 

approval of the affirmative defense was premised upon its only applying to civil penalties and 

not to injunctive relief and that the Agency’s approval of the SIP provision was explicitly upheld 

on this basis by the Fifth Circuit. Nevertheless, the commenter asserted, the state agency has 

implemented this provision such that if the affirmative defense criteria are met, there is “no 

violation” and thus no potential for injunctive relief. 

Response: The EPA agrees that some of the affirmative defense provisions at issue in this 

action are expressly limited to monetary penalties and not to injunctive relief. This approach was 

consistent with the EPA’s prior interpretation of the CAA concerning affirmative defense 

provisions in SIPs but also consistent with the arguments that the D.C. Circuit rejected in the 

NRDC v. EPA decision. Thus, the fact that some of the affirmative defense provisions addressed 

in this action preserve the possibility for injunctive relief, even if the court could award no 

monetary penalties, is no longer a deciding factor. 

The EPA also agrees that some agencies or courts may not apply the affirmative defense 

provisions in the manner intended at the time the EPA approved them into the SIP. Incorrect 

application of SIP affirmative defense provisions by sources, regulators or courts is a matter of 

concern. At this juncture, however, even perfect implementation of a SIP affirmative defense 
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provision does not cure the underlying absence of a legal basis for such provisions. Again, the 

fact that a given affirmative defense provision is being implemented correctly or incorrectly is no 

longer a deciding factor for purposes of this SIP call action. 

These issues are not pertinent to the EPA’s decision in this action to require states to 

remove the affirmative defense provisions from the previously approved SIPs. Rather, as 

explained in detail in the SNPR and this final action, the EPA is requiring the affected states to 

remove these SIP provisions because they are inconsistent with CAA requirements. As explained 

in the SNPR, the EPA has concluded that such affirmative defenses in SIP provisions are 

inconsistent with section 113 and section 304, in light of the reasoning of the court in NRDC v. 

EPA. 

17. Comments that the EPA is changing its policy on affirmative defenses, which is arbitrary 

and capricious and an impermissible basis for a SIP call. 

Comment: Several commenters stated that the EPA’s action with respect to affirmative 

defense provisions marks a change in the EPA’s approach to these provisions. The commenters 

alleged that this SIP call action is not mandated by judicial precedent, and therefore the SNPR 

simply reflected a “policy change” by the EPA. The commenters argued that, while the EPA is 

permitted to change its policy or interpretation of the law, this specific change is arbitrary and 

capricious and forces unreasonably difficult and burdensome requirements on states and sources. 

The commenters asserted that the EPA failed to explain adequately this change in policy or to 

document reasons for the change in the administrative record. Some commenters further alleged 

that the EPA does not have authority to impose its policy preferences on states. 

Response: The EPA disagrees that the basis for this SIP call action is a change of 

“policy” as alleged by the commenters. The EPA’s guidance to states concerning the proper 
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treatment of excess emissions during SSM events in SIP provisions is provided in the SSM 

Policy, but this guidance reflects the Agency’s interpretation of statutory requirements. As 

explained in detail in the SNPR and in this document, the EPA is changing its interpretation of 

the CAA with respect to affirmative defenses in SIP provisions based on the logic of the court in 

NRDC v. EPA. Further, as acknowledged by commenters, the EPA is permitted to change its 

interpretation of the statute provided that it clearly explains the basis for the change. The EPA 

clearly explained the basis for the changed interpretation in the SNPR based on its analysis of the 

legal rationale respecting sections 113 and 304 in the NRDC v. EPA decision. 

18. Comments that emissions during malfunction periods are not “excess” or “violations,” 

but rather are part of the established SIP emission limitations. 

Comment: Commenters cited the EPA’s brief filed in the Fifth Circuit Luminant 

Generation v. EPA case in support of an argument that states are not required to attach a penalty 

or any certain amount of penalty to a violation of a SIP emission limitation. The commenters 

noted that in the brief, the EPA stated that under section 110 of the CAA, states are authorized 

“to determine what constitutes a violation, and to distinguish both quantitatively and 

qualitatively between different types of violations.” Further, the commenter noted, the EPA 

argued in the brief that because the violation is defined by the state, an affirmative defense does 

not impinge of the court’s jurisdiction. The commenters contended that nothing has changed 

since the brief was filed to justify a change in interpretation of the CAA and that the EPA failed 

to explain why its prior interpretation is no longer correct. 

Other commenters claimed that the EPA takes the position that affirmative defenses in 

SIP provisions conflict with the court’s jurisdiction over enforcement actions and stated that this 

position is flawed because enforcement is limited to violations as defined in the context of the 
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SIP. The commenters asserted that section 304 does not apply when there is no SIP requirement 

being violated and that the state has the authority to define what constitutes such a violation. 

Similarly, commenters argued that an affirmative defense provision may provide that emissions 

will not be “violations” if criteria are met and therefore do not interfere with a court’s ability to 

determine appropriate penalty amounts under 113. The commenters contended, because the state 

has the authority to define what constitutes a violation, SIP provisions that include an affirmative 

defense do not infringe on a court’s authority to penalize a source because the CAA does not 

provide a court with jurisdiction to impose remedies in the absence of liability. 

Response: The EPA explained in detail the rationale for its change in interpretation of the 

CAA regarding affirmative defenses in the SNPR. The EPA acknowledges that in the Luminant 

Generation v. EPA case, the Agency argued that states are authorized to determine what 

constitutes a violation and to distinguish between different types of violations. As the EPA 

explained in the SNPR, the court in Luminant Generation v. EPA held that the Agency’s 

interpretation of the CAA to permit affirmative defenses applicable to malfunctions at that time 

was a “permissible interpretation of section [113], warranting deference.” The same court also 

upheld the EPA’s interpretation of the CAA to preclude affirmative defenses for planned events 

on the same basis that it was a reasonable interpretation of the CAA. However, the EPA has 

reevaluated this interpretation of the CAA requirements in light of the more recent NRDC v. EPA

decision, and the Agency now believes that its prior interpretation of the CAA with respect to the 

approvability of affirmative defense provisions in SIPs is no longer the best reading of the 

statute. Thus, the Agency’s view now is that a “violation” cannot be defined in a manner that 

interferes with the court’s role in assessing remedies. It is irrelevant that the EPA had argued for 

a different interpretation in the past as the Agency now believes that the court’s analysis in 
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NRDC v. EPA is the better reading of the provisions of the statute concerning affirmative 

defenses. The EPA has authority to revise its prior interpretation of the CAA when further 

consideration indicates to the Agency that its prior interpretation of the statute is incorrect. The 

EPA fully explained the basis for this change in its interpretation of the CAA in the SNPR. 

The EPA agrees that in some cases, affirmative defense provisions at issue in this SIP call 

action are structured as a complete defense to any liability, not merely a defense to monetary 

penalties. The EPA has also determined that affirmative defense provisions of this type are 

substantially inadequate to meet CAA requirements. Although such affirmative defenses may not 

present the same concerns as affirmative defenses applicable only to penalties, such affirmative 

defenses may create a different concern because they in effect provide a conditional exemption 

from otherwise applicable emission limitations. If there is no “violation”when the criteria of such 

an “affirmative defense” are met and no legitimate alternative emission limitation applies during 

that event, then such an affirmative defense in effect operates to create a conditional exemption 

from applicable emission limitations. This form of “affirmative defense” provision therefore runs 

afoul of different CAA requirements for SIP provisions. Under section 302(k) of the CAA, 

emissions standards or limitations must be continuous and cannot include SSM exemptions, 

automatic or otherwise. Regardless of whether the commenters believe that this form of 

“affirmative defense” should be allowed, the EPA believes that provisions of this form are 

inconsistent with the decision of the court in Sierra Club v. Johnson. In that case, the court held 

that emission limitations under the CAA must impose continuous controls and cannot include 

exemptions for emissions during SSM events. The EPA concludes that making the exemptions 

from emission limitations conditional does not alter the fact that once exercised they are illegal 

exemptions. 
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19. Comments that the definition of “emission limitation” in CAA section 302(k) does not 

support this SIP call action. 

Comment: Several commenters noted that while the EPA depends on the definition of 

“emission limitation” in the CAA section 302(k) for this action, that CAA provision does not 

support this SIP call action, including that the CAA does not require that SIPs contain continuous 

emissions standards in the form asserted by the EPA. The commenters alleged that the definition 

in the CAA and supporting materials interpreting that definition do not support the EPA’s 

requiring one emission limitation to apply in all circumstances at all times. Some commenters 

further alleged that states subject to the EPA’s SIP call action have implementation plans that 

provide emission limitations that apply continuously through a combination of numerical 

emission limitations, the general duty to minimize emissions and the affirmative defense criteria 

for excess emissions during malfunctions. 

Several commenters questioned why, even if the challenged affirmative defense 

provisions do not qualify as “emission limitations” or “emissions standards” under the first part 

of the definition, they are not approvable as “design, equipment, work practice or operational 

standards” promulgated under the second part of the definition. Some commenters argued that, to 

the extent that affirmative defense provisions in SIPs do not satisfy the definition of “emission 

limitation,” they would still be approvable elements of a SIP as “other control measures, means, 

or techniques” allowed under CAA section 110(a)(2). Further, some commenters believe that the 

legislative history cited in the EPA’s SNPR does not support the EPA’s position but rather is 

only intended to preclude the use of dispersion techniques, such as intermittent controls. 

One commenter stated that the Portland Cement NESHAP, at issue in the NRDC v. EPA

decision, was classified by statute as an “emissions standard,” a term defined by the CAA and 
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defined as applying “on a continuous basis.” The commenter stated that SIP provisions involve 

more than “emissions standards” and need not be “emissions standards.”54 Thus, according to the 

commenter, the NRDC v. EPA decision does not apply to SIP rules. 

Response: The commenters alleged that the EPA’s interpretation of the CAA section 

302(k) definition of “emission limitation” in this action was inappropriate and that section 302(k) 

does not support this SIP call action. The EPA notes that it is not the Agency’s position that all 

emission limitations in SIP provisions must be set at the same numerical level for all modes of 

source operation or even that they must be expressed numerically at all. To the contrary, the EPA 

intended to indicate in the proposal documents that states may elect to create emission limitations 

that include alternative emission limitations, including specific technological controls or work 

practices, that apply during certain modes of source operation such as startup and shutdown. 

However, this comment is not relevant to the issue of affirmative defense provisions in SIPs. It is 

not for the reason that affirmative defense provisions do not meet the definition of an “emission 

limitation” in section 302(k) that the EPA is promulgating this SIP call action for affirmative 

defense provisions. The EPA has concluded that affirmative defense provisions are substantially 

inadequate to meet CAA requirements concerning enforcement, in particular the requirements of 

section 113 and section 304. 

As to commenters’ argument that affirmative defense provisions can be appropriately 

considered to be “design, equipment, work practice or operational standards” under CAA section 

302(k), the critical aspect of an emission limitation in general is that it be a “requirement . . . 

which limits the quantity, rate, or concentration of emissions of air pollutants on a continuous 

 

54 See CAA section 110(a)(2)(A). 
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basis . . . .” These provisions operate to excuse sources from liability for emissions under certain 

conditions, not to limit the emissions in question. The affirmative defense provisions at issue in 

this final action do not themselves, or in combination with other components of the emission 

limitation, limit the quantity, rate or concentration of air pollutants on a continuous basis. These 

affirmative defense provisions, therefore, do not themselves meet the statutory definition of an 

emission limitation under section 302(k). 

The EPA notes that the definition of “emission limitation” in section 302(k) is relevant, 

however, with respect to those affirmative defense provisions that commenters claim are merely 

a means to define what constitutes a “violation” of an applicable SIP emission limitation. As 

previously explained, the EPA believes that an “affirmative defense” structured in such a fashion 

is deficient because it in effect creates a conditional exemption from the SIP emission 

limitations. By creating such exemptions, conditional or otherwise, an affirmative defense of this 

type would render the emission limitations less than continuous. 

The EPA disagrees with commenters’ remaining points because the EPA’s position on 

what appropriately qualifies as an emission limitation is consistent with the CAA, relevant 

legislative history and case law. These issues are addressed in more detail in sections VII.A.3.i 

through 3.j of this document. 

20. Comments that the EPA has failed to show state SIPs are substantially inadequate, as is 

required to promulgate a SIP call. 

Comment: Several commenters noted that before the EPA can issue a SIP call under 

section 110(k)(5) with respect to affirmative defense provisions, the EPA must determine that a 

SIP provision is “substantially inadequate to attain or maintain the relevant [NAAQS], to 

mitigate adequately the interstate pollutant transport described in section 7506a of this title or 
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section 7511c of this title, or to otherwise comply with any requirement of this chapter.” The 

commenters further stated that Congress employed a high bar in the language of CAA section 

110(k)(5) in requiring the EPA to find “substantial” inadequacies, as opposed to other CAA 

provisions that permit the Agency to act based on “discretion” or when it “may be appropriate.” 

The commenters alleged that the EPA has not demonstrated a “substantial inadequacy” with 

respect to the affirmative defense provisions at issue in the SNPR, as required to issue a SIP call. 

Some commenters also argued that the EPA has failed in its SNPR to define or interpret 

“substantially inadequate” or provide any standards for assessing the adequacy of a SIP with 

respect to affirmative defense provisions. The commenters also alleged that, if the EPA is 

required to rely on data and evidence in evaluating SIP revisions, it follows that the EPA should 

produce at least the same level of data and evidence, if not more, to support a SIP call that is 

based on the more stringent substantial inadequacy standard of section 110(k)(5). 

Response: The EPA disagrees with the commenters’ arguments that the Agency has 

failed to establish that the affirmative defense provisions identified in the SNPR are 

“substantially inadequate” as required by section 110(k)(5). As explained in the SNPR and this 

action, the EPA has determined that affirmative defense provisions at issue in this action are 

substantially inadequate because they are inconsistent with applicable legal requirements of the 

CAA. The commenters raised similar arguments with respect to the EPA’s authority to issue a 

SIP call to address other forms of deficient SIP provisions, such as automatic or discretionary 

exemptions from emission limitations. The EPA responds to these broader arguments in sections 

VIII.D.46 through D.48 of this document. 

21. Comments that this action is not national in scope, and therefore the D.C. Circuit is not 

the sole venue for review of this action. 
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Comment: Several commenters claimed that the EPA is incorrect in stating that this SIP 

call action is a single nationally applicable action and of nationwide scope or effect. The 

commenters alleged that review of all affected SIP provisions in a single action in the D.C. 

Circuit would inappropriately limit the scope of review by obscuring distinctions between the 

various states’ regulatory programs and practical concerns. The commenters asserted that none 

of the various state SIP provisions addressed in the SNPR were the same, and the EPA analyzed 

each separately and provided case-by-case justification for its proposed action as to each. 

Further, the commenters argued that although the EPA has packaged the SIP calls in one Federal 

Register notice, any final action that the EPA takes with respect to a single state’s affirmative 

defense provision is only locally applicable and therefore should be reviewed in the individual 

circuits with jurisdiction over the affected state. One commenter further contended that, while 

the EPA’s revised SSM Policy may be of interest to states to which the SIP call does not directly 

apply, that does not make the rule “nationally applicable.” 

The commenters acknowledged that the EPA cited Texas v. EPA in support of its 

assertion, but the commenters allege that the Fifth Circuit in that case never reached the issue of 

nationwide scope and effect.55 The commenters claimed that this SIP call action is distinct from 

the rule at issue in Texas v. EPA because this final action turns on the particulars of the SIP call 

action’s impact on each individual state’s SIP. One commenter also claimed that the EPA has 

failed to provide authority or a legal basis to support its determination that this rulemaking is of 

“nationwide scope or effect.” Such failure, according to the commenter, violated the 

 

55 See No. 10-60961, 2011 WL 710598 (5th Cir. Feb. 24, 2011). 
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requirements of section 307(d)(3) and did not allow for full and meaningful comment on this 

issue. 

One commenter alleged that the EPA has waived its challenge to venue for those circuits 

that have already weighed in regarding individual state SIP provisions at issue in this action, 

including Texas’s affirmative defense provisions. Another commenter claimed that the 

discussion over appropriate venue in the February 2013 proposal and SNPR presupposes that the 

EPA’s issuance of a revised SSM Policy is a “final agency action” subject to judicial review 

under section 307(b)(1) but argued that the EPA has failed to determine that its issuance of the 

SSM Policy, in and of itself, constitutes “final agency action.” 

Response: The EPA disagrees with the commenters’ theories concerning the scope of the 

Agency’s action. These comments on the SNPR questioning the EPA’s determination of 

“nationwide scope and effect” for this action largely repeat similar comments on the February 

2013 proposal. As with those prior comments, commenters on the SNPR made the basic 

argument that this action is not of nationwide scope and effect because the EPA is reviewing 

individual SIP provisions and directing states to correct their respective deficient SIP provisions. 

The EPA disagrees with commenters because, as explained in more detail in its response in 

section V.D.6 of this document, this rulemaking action applies the same “process and standard” 

to numerous areas across the country. While it is correct that the SIP submissions that states 

make in response to this SIP call will be reviewed separately by the EPA and subsequently 

subject to potential judicial review in various circuits, the EPA’s legal interpretation of the CAA 

concerning permissible SIP provisions to address emissions during SSM events in this action is 

nationally applicable to all states subject to the SIP call. The EPA provided a full explanation of 
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its basis for this determination of nationwide scope and effect in the February 2013 proposal and 

the SNPR. 

The EPA also disagrees with the argument that the Agency has waived venue regarding 

challenges to this SIP call action concerning the affirmative defense provisions in the Texas SIP. 

Evidently, the commenter believes that because a prior challenge to another EPA rulemaking 

concerning the affirmative defense provisions occurred in the Fifth Circuit, it necessarily follows 

that any other rulemaking related to such provisions can only occur in the Fifth Circuit. The EPA 

believes that this interpretation of its authority under section 307(b)(1) is simply incorrect. Under 

section 307(b)(1), the EPA is explicitly authorized to make a determination that a specific 

rulemaking action is of “nationwide scope and effect.” The statute does not specify the 

considerations that the EPA is to take into account when making such a determination, let alone 

provide that the Agency cannot invoke this because some aspect of the rulemaking at issue might 

previously have been addressed in one or more other circuit courts. To the contrary, the EPA 

believes that section 307(b)(1) explicitly provides authority for the Agency to determine that a 

given rulemaking should be reviewed in the D.C. Circuit in situations such as those presented in 

this action that affects important questions of statutory interpretation that affect states 

nationwide. 

The EPA likewise disagrees with the argument that its action, including the issuance of 

the revised and updated SSM Policy of 2015, is not a final agency action. Within this action, the 

EPA is taking final agency action to respond to the Petition, updating its interpretations of the 

CAA in the SSM Policy and applying its interpretations of the CAA in the SSM Policy to 

specific SIP provisions in the SIPs of many states. The EPA is conducting this action through 

notice-and-comment rulemaking to assure full consideration of the issues. The EPA’s 
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interpretations of the CAA requirements for SIP provisions applicable to emissions during SSM 

events are part of the final agency action and are subject to judicial review. To the extent the 

commenters are arguing that the issuance of the updated SSM Policy in and of itself is not final 

agency action, the EPA notes that the commenters are at liberty to adopt this position and waive 

their opportunity to challenge the SSM Policy because they do not consider it final agency 

action. 

22. Comments that the EPA should clarify that SIPs can include work practice standards or 

general-duty clauses to apply during malfunction periods in place of affirmative defense 

provisions. 

Comment: Several commenters stated that the EPA should announce in this final action 

that in lieu of affirmative defenses, states may elect to revise their SIP provisions to include work 

practice standards or general-duty clauses that are modeled on existing affirmative defense 

provisions and that would apply during malfunctions. Most of these commenters advocated that 

the EPA’s previously recommended criteria for an “affirmative defense” for malfunctions should 

simply be changed into criteria for a “work practice” provision instead. One commenter made 

the same suggestion but also advocated that the EPA eliminate six of the nine criteria and 

rephrase the remaining criteria, in order to “improve the standards, reduce uncertainty, and 

reduce wasteful litigation.” This commenter advocated that the EPA also redefine the term 

“malfunction” to much more broadly mean any “sudden and unavoidable breakdown of process 

or control equipment.” Specifically, the commenter advocated, the EPA should no longer 

recommend that a malfunction be defined as an event that: (i) was caused by a sudden, 

infrequent and unavoidable failure of air pollution control equipment, process equipment or a 

process to operate in a normal or usual manner; (ii) could not have been prevented through 
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careful planning, proper design or better operation and maintenance practices; (iii) did not stem 

from any activity or event that could have been foreseen and avoided or planned for; and (iv) 

was not part of a recurring pattern indicative of inadequate design, operation or maintenance. By 

changing the “affirmative defense” provisions for malfunctions into “work practice” or “general 

duty” provisions for malfunctions, the commenters argued, the revised provisions would be 

consistent with CAA requirements. Under this approach, the commenters asserted that 

compliance with these new requirements would mean that any emissions during a malfunction 

event could not be considered “excess” or result in any violation if the source had complied with 

the “work practice” criteria. 

Response: As an initial matter, the EPA has not established a regulatory definition of 

“malfunction” that is binding on states when developing SIPs. States have the flexibility in their 

SIPs to define that term. Thus, the EPA is not addressing here the comments requesting EPA to 

“redefine” the definition of malfunction. 

Regarding the more general concern of the commenters, that states be allowed to 

establish an alternative emission limitation in the form of a work practice standard that applies 

during malfunctions, the EPA notes two points. First, the CAA does not preclude that emissions 

during malfunctions could be addressed by an alternative emission limitation. The EPA’s general 

position in the context of standards under sections 111, 112 and 129 is that: (i) the applicable 

emission limitation applies at all times including during malfunctions; (ii) the CAA does not 

require the EPA to take into account emissions that occur during periods of malfunction when 

setting such standards; and (iii) accounting for malfunctions would be difficult, if not impossible, 

given the myriad types of malfunctions that can occur across all sources in a source category and 

given the difficulties associated with predicting or accounting for the frequency, degree and 
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duration of various malfunctions that might occur. Although the EPA has not found it practicable 

to-date to develop emission standards that apply during periods of malfunction in place of an 

otherwise applicable emission limitation, this does not preclude the possibility that a state may 

determine that it can do so for all or some set of malfunctions. Second, states are not bound to 

establish any specific definition of “malfunction” in their SIPs. Thus, it is difficult to judge at 

this time whether any particular alternative emission limitation in a SIP for malfunctions, 

including any specific work practice requirements in place of an otherwise applicable emission 

limitation, would be approvable. 

With regard to the specific comment that the affirmative defense criteria could be 

converted into a work practice requirement to apply during malfunctions in place of an otherwise 

applicable emission limitation, the EPA is unsure at this time whether the criteria previously 

recommended for an affirmative defense provision would meet the obligation to develop an 

appropriate alternative emission limitation. Existing affirmative defense criteria (which include, 

among other things, making repairs expeditiously, taking all possible steps to minimize 

emissions and operating in a manner consistent with good practices for minimizing emissions) 

were developed in the context of helping to determine whether a source should be excused from 

monetary penalties for violations of CAA requirements and were not developed in the context of 

establishing an enforceable alternative emission limitation under the Act. The EPA would need 

to consider this approach in the context of a specific SIP regulation for a specific type of source 

and emission control system. 

Finally, the EPA notes that any emission limitation, including an alternative emission 

limitation, that applies during a malfunction must meet the applicable stringency requirements 

for that type of SIP provision (e.g., would need to meet RACT for sources subject to the RACT 
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requirement) and must be legally and practically enforceable. Thus, the SIP provision would 

need to: (i) clearly define when the alternative emission limitation applied and the otherwise 

applicable emission limitation did not; (ii) clearly spell out the requirements of that standard; and 

(iii) include adequate monitoring, recordkeeping and reporting requirements in order to make it 

enforceable. In addition, the state would need to include emissions attributable to these foreseen 

events in emissions inventories, modeling demonstrations and other regulatory contexts as 

appropriate. 

23. Comments that the EPA has failed to account adequately for the cost of this SIP call 

action and is therefore in violation of the Regulatory Flexibility Act, the Unfunded Mandates 

Reform Act and Administration policy. 

Comment: Two commenters argued that the SNPR lacks sufficient analysis of what this 

action will cost states, stationary sources and the public. The commenters allege that this absence 

of economic impact analysis is contrary to the Regulatory Flexibility Act, the Unfunded 

Mandates Reform Act and Administration policy. One of the commenters also noted that 

imposing substantial “unfunded mandates” on state regulatory agencies and forcing stationary 

sources to absorb additional costs should be evaluated carefully. 

Response: The EPA disagrees with the commenters’ allegation that the EPA has failed to 

comply with relevant statutes and Administration policy in accounting for the cost of the actions 

proposed in the SNPR. The EPA did in fact properly consider the costs imposed by this action. 

These issues are addressed in more detail in section V.D.7 of this document. 

24. Comments that states should not be required to eliminate affirmative defense provisions 

but rather should be allowed to revise them to be appropriate under CAA requirements. 
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Comment: One state commenter claimed that it should be allowed to revise its existing 

affirmative defense provisions rather than remove them. The commenter asserted that the state 

should be allowed to revise the provision to make clear that it does not apply to private 

enforcement actions under CAA section 304(a), which was the only issue specifically before the 

court in NRDC v. EPA. Relying on the court’s decision, the commenter claimed that the state 

should be allowed to revise the affirmative defense provisions to apply only in administrative 

enforcement proceedings. The commenter also argued that there may be other options for 

appropriately tailoring the state’s existing affirmative defense provisions rather than removing 

them from the SIP. 

Response: The EPA agrees that the court in NRDC v. EPA did not directly address 

whether states have authority to create affirmative defense provisions that apply exclusively to 

state personnel in the context of state administrative enforcement actions. Statements by the 

court concerning the EPA’s own authority in the context of administrative enforcement, 

however, indicate that the court did not intend to foreclose the Agency from exercising its own 

enforcement discretion with respect to remedies in federal administrative enforcement actions. 

However, the EPA has reevaluated its interpretation of CAA requirements in light of the court’s 

decision in NRDC v. EPA and the EPA now interprets the CAA to preclude state SIP provisions 

creating affirmative defenses that sources could assert in the context of judicial enforcement in 

federal court, whether initiated by states, the EPA, or other parties pursuant to section 304. 

The EPA agrees that states may elect to revise their existing deficient affirmative defense 

provisions to make them “enforcement discretion”-type provisions that apply only in the context 

of administrative enforcement by the state. Such revised provisions would need to be 

unequivocally clear that they do not provide an affirmative defense that sources can raise in a 
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judicial enforcement context or against any party other than the state. Moreover, such provisions 

would have to make clear that the assertion of an affirmative defense by the source in a state 

administrative enforcement context has no bearing on the additional remedies that the EPA or 

other parties may seek for the same violation in federal administrative enforcement proceedings 

or judicial proceedings. 

In this action, the EPA is not determining whether any such revisions would meet 

applicable CAA requirements. The EPA would need to consider the precise wording of any such 

revised provisions in evaluating whether the state has adequate enforcement authority to meet the 

requirements of section 110(a)(2)(C) and also whether application of such a provision in a state 

administrative proceeding could interfere with the ability of a citizen or the EPA to bring a 

federal enforcement action. 

25. Comments that states’ ability to use enforcement discretion is not an adequate 

replacement for affirmative defense provisions. 

Comment: Several commenters argued that exercise of enforcement discretion is not an 

adequate substitute for an affirmative defense, particularly where the emissions at issue resulted 

from an inevitable and unavoidable malfunction. In any individual case, the commenters were 

concerned that even if a state elects not to enforce against a violation, the EPA or others might 

elect to bring an enforcement action. One commenter contended that it is inappropriate for the 

EPA to encourage states to use enforcement discretion instead of encouraging them to create 

alternative emission limitations to replace affirmative defenses in SIP provisions. The 

commenters also alleged that reliance on judicial discretion to determine the appropriateness of 

penalties is similarly inadequate. 
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The commenters contended that, although it is reasonable for a state to exercise 

enforcement discretion under circumstances when an emission limitation cannot be met, it is not 

reasonable to adopt SIP provisions with emission limitations that put some sources in the 

position of “repeated noncompliance.” 

Response: These comments addressing whether an enforcement discretion approach is 

sufficient are similar to comments received on the February 2013 proposal to which the EPA 

responds in section VII.A.3.p of this document. Through this SIP call, the EPA is not requiring 

states to rely on enforcement discretion in place of achievable SIP emission limitations. Rather, 

the EPA is requiring states to ensure that emission limitations are consistent with the definition 

of that term in section 302(k), and specifically that emission standards provide for continuous 

compliance. If emission limitations that apply during routine operations cannot be met by a 

source during periods of startup or shutdown, states have authority to establish alternative 

emission standards. The EPA disagrees that an affirmative defense for penalties for excess 

emissions for periods of malfunctions is an adequate substitute for an enforceable continuous 

emission limitation and concludes that such an approach is inconsistent with the CAA as 

interpreted by the court in NRDC, as explained in the SNPR. 

The EPA also disagrees that affirmative defense provisions would have been appropriate 

to address the “repeated noncompliance” concerns of the commenters. The EPA’s prior 

interpretation of the CAA was that states could create narrowly tailored affirmative defense 

provisions applicable to malfunctions. However to the extent that there are malfunctions that put 

a source in the position of “repeated noncompliance,” the form of affirmative defense that the 

EPA previously believed was consistent with the CAA would not have provided relief because 

several of the criteria could not be met. Specifically, the EPA believes repeated noncompliance is 
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typically a result of inadequate design, is part of a “recurring pattern,” and thus likely could have 

been “foreseen and avoided.” In short, an affirmative defense would not have been appropriate 

for such a source. 

26. Comments that the EPA should establish specific rules to govern how states set 

alternative limitations that apply in lieu of affirmative defense provisions. 

Comment: Commenters urged the EPA to clarify in this final rule that states may 

establish alternative emission limitations applicable to startup and shutdown only if the source 

meets all applicable CAA requirements, including but not limited to BACT/LAER, and the state 

also demonstrates through modeling that potential worst-case emissions from startup and 

shutdown would not interfere with attainment and reasonable further progress. Other 

commenters stated that any changes to SIP emission limitations must be made as part of a SIP 

revision process, which would include a demonstration that higher levels of emissions during 

startup and/or shutdown would not lead to violations of the NAAQS or PSD increments. 

Commenters also argued that any such alternative emission limitation should “sunset” 

each time the EPA promulgates a new NAAQS and that the Agency should require the state to 

demonstrate again that an alternative emission limitation applicable during startup and/or 

shutdown does not interfere with attainment or other applicable requirements of the CAA for the 

revised NAAQS. In support of their arguments that the EPA should impose specific requirements 

of this type, the commenters indicated that a state has issued permits for sources that establish 

particulate matter (PM) emission limitations less stringent than existing permit terms and without 

requiring a BACT/LAER/ambient impacts analysis and has done so without public notice and 

comment. Commenters urged the EPA to require states to follow public notice-and-comment 
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processes before issuing any permits for sources with alternative limitations less stringent than 

those imposed by the SIP and claimed such process is required under the CAA. 

In addition, some commenters stated that if the EPA allows states to set “new, higher, or 

alternate limits” applicable during startup and shutdown, the EPA should set clear parameters. 

According to commenters, the EPA at a minimum should require, for emissions that have not 

previously been authorized or considered part of a source’s potential to emit, that: (i) limitations 

must meet BACT/LAER; (ii) there should be clear, enforceable rules for when alternate 

limitations apply; (iii) there should be a demonstration that worst-case emissions will not cause 

or contribute to a violation of the NAAQS or PSD increments; and (iv) proposed limitations 

should be subject to public notice and comment and judicial review. The commenter pointed to a 

letter from the EPA to Texas in which, the commenter claims, the Agency indicated that these 

parameters must be met. 

A commenter stated that the EPA should unequivocally state in this final rule that: (i) all 

potential to emit emissions, including quantifiable emissions associated with startup and 

shutdown, must be included in federal applicability determinations and air quality permit 

reviews; (ii) authorization of these emissions must include technology reviews and impacts 

analyses; and (iii) the above requirements must be included in the permit that authorizes routine 

emissions from the applicable units and must be subject to public notice, comment and judicial 

review. 

A commenter recognized that there may be a variety of ways in which states can 

authorize higher limits during startup and shutdown but argued that, no matter the method 

chosen, the emissions need to be fully accounted for by the state in the relevant SIP, including a 
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demonstration that the additional emissions authorized during startup and shutdown will not 

violate any NAAQS. 

Response: The EPA understands the concerns raised by the commenters but does not 

agree that further regulatory action such as issuance of regulatory text is necessary at this time. 

Through this action, the EPA is providing comprehensive guidance to states concerning issues 

related to the proper treatment of emissions during SSM events in SIP provisions. For example, 

the EPA is addressing the concern raised by commenters that states will need to ensure that any 

SIP revisions in response to this SIP call will meet applicable CAA requirements. Under section 

110(k)(3), the EPA has authority to approve SIP revisions only if they comply with CAA 

requirements. Moreover, under section 110(l), the EPA cannot approve SIP revisions if they 

would “interfere with any applicable requirement concerning attainment and reasonable further 

progress ... or any other applicable requirement” of the CAA. The EPA believes that both states 

and the Agency can address these issues in SIP rulemakings without the need for any additional 

federal regulations as suggested by the commenters. 

The EPA agrees with the concerns raised by the commenters regarding instances where a 

state has issued source permits that impose less stringent emission limitations than otherwise 

established in the SIP. Using a permitting process to create exemptions from emission limitations 

in SIP emission limitations applicable to the source is tantamount to revising the SIP without 

meeting the procedural and substantive requirements for a SIP revision. The Agency’s views on 

this issue are described in more detail in section VII.C.3.e of this document. 

The EPA does not agree with the comment that suggests “worst-case modeling” would 

always be needed to show that a SIP revision establishing alternative emission limitations for 

startup and shutdown would not interfere with attainment or reasonable further progress. The 
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nature of the technical demonstration needed under section 110(l) to support approval of a SIP 

revision depends on the facts and circumstances of the SIP revision at issue. The EPA will 

evaluate SIP submissions that create alternative emission limitations applicable to certain modes 

of operation such as startup and shutdown carefully and will work with the states to assure that 

any such limitations are consistent with applicable CAA requirements. Under certain 

circumstances, there may be alternative emission limitations that necessitate a modeling of 

worst-case scenarios, but those will be determined on a case-by-case basis. 

The EPA also does not agree that existing SIP provisions with alternative emission 

limitations should automatically “sunset” upon promulgation of a new or revised NAAQS. Such 

a process could result in gaps in the state’s regulatory structure that could lead to backsliding. 

When the EPA promulgates new or revised NAAQS, it has historically issued rules or guidance 

to states concerning how to address the transition to the new NAAQS. In this process, the EPA 

typically addresses how states should reexamine existing SIP emission limitations to determine 

whether they should be revised. With respect to technology-based rules, the EPA has typically 

taken the position that states need not adopt new SIP emission limitations for sources where the 

state can demonstrate that existing SIP provisions still meet the relevant statutory obligations. 

For example, the EPA believes that states can establish that existing SIP provisions still represent 

RACT for a specific source or source category for a revised NAAQS. In making this 

determination, states would need to review the entire emission limitation, including any 

alternative numerical limitations, control technologies or work practices that apply during modes 

of operation such as startup and shutdown, and ensure that all components of the SIP emission 

limitation meet all applicable CAA requirements. 
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27. Comments that the EPA should closely monitor states’ SIP revisions in response to this 

SIP call. 

Comment: Commenters urged the EPA to monitor states’ efforts to revise SIPs in 

response to the SIP call closely in order to assure that the revisions meet all applicable 

requirements. The commenters indicated concern that states and industry may weaken emission 

limitations through this process. The commenter alleged that one state has issued permits for 

sources with emission limitations applicable during SSM events that are less stringent than the 

emission limitations approved in the SIP. Furthermore, the commenter alleged, the state issued 

these permits without public notice and comment. As support for this contention, the commenter 

detailed the differences between the requirements of a permit issued for a source and the 

requirements in the SIP. The commenter also claimed that the state has issued permits for other 

facilities similar to the one it described in detail in the comments. 

Response: The EPA understands the concerns expressed by the commenter that SIP 

revisions made in response to this SIP call need to be consistent with CAA requirements. As 

explained in this document, the states and the EPA will work to assure that the SIP revisions will 

meet applicable legal requirements. The EPA will evaluate these SIP submissions consistent with 

its obligations under section 110(k)(3), section 110(l), section 193 and any other substantive 

provisions of the CAA applicable to specific SIP submissions. 

To the extent that the commenters are concerned about whether the SIP revisions meet 

applicable requirements, they will have the opportunity to participate in the development of those 

revisions. States must submit SIP revisions following an opportunity for comment at the state 

level. Additionally, the EPA acts on SIP submissions through its own notice-and-comment 

process. As part of these administrative processes, both the state and the EPA will need to 
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evaluate whether the proposed revision to the SIP meets applicable CAA requirements. In the 

context of those future rulemaking actions, the public will have a chance to review the substance 

of the specific SIP revisions in response to this SIP call, as well as the state’s and the EPA’s 

analysis of the SIP submissions for compliance with the CAA. 

28. Comments that the EPA does not have authority to take this action without Congressional 

authorization. 

Comment: A commenter contended that the EPA does not have the authority to write law 

and that the EPA should be required to seek changes to the applicable law through Congress, 

before eliminating affirmative defense and due process provisions from SIPs. 

Response: Through this action the EPA is not attempting to rewrite the CAA. Rather, the 

EPA is requiring states to revise specific SIP provisions to comply with the existing requirements 

of the CAA, as interpreted by the courts. As explained in detail in the SNPR and this notice, the 

EPA has determined that affirmative defense provisions at issue in this action are inconsistent 

with the existing requirements of the CAA. 

29. Comments that affirmative defense provisions are needed to ensure sources’ 

Constitutional right to due process in the event of violations. 

Comment: A number of commenters argued that by requiring the removal of affirmative 

defense provisions from SIPs, the EPA is impinging on the Constitutional rights of sources that 

may have wanted to assert such affirmative defenses in an enforcement action. A commenter 

claimed that affirmative defense provisions are not “loop holes,” as alleged by the EPA, but 

instead are fundamental due process provisions which should be retained at all levels for the 

protection of the public. Another commenter cited State Farm Mut. Auto Ins. Co. v. Campbell, 

for the proposition that a monetary penalty that is “grossly excessive ... constitutes an arbitrary 
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deprivation of property.”56 Other commenters claimed that excessive penalties constitute an 

arbitrary deprivation of property. The commenters asserted that a penalty is excessive where it 

applies severe punishment to an act that is unavoidable. 

Response: The commenters’ due process concerns suggest that without an affirmative 

defense provision, any penalty assessed for violation of a SIP would be per se “excessive” or 

“arbitrary.” Though not expressly stated, some of these comments appear to suggest that the 

existing CAA enforcement provisions are facially unconstitutional. The EPA disagrees. The 

CAA does not mandate that any penalty is automatically assessed for a violation. Rather the 

CAA establishes a maximum civil penalty in section 113(b) but then expressly provides in 

section 113(e) the criteria that the EPA or the courts (as appropriate in administrative or judicial 

enforcement) “shall take into consideration (in addition to other factors as justice may require).” 

These criteria explicitly include consideration of “good faith efforts to comply.” Thus, the CAA 

on its face does not mandate the imposition of any penalty automatically, much less one that is 

per se excessive. Notably, the commenters do not elaborate on how or why they believe the 

statutory penalty provisions of the CAA are facially unconstitutional, instead making generalized 

claims. 

To the extent that the commenters are raising an “as applied” claim of unconstitutionality, 

any such claim can be raised in the future in the context of a specific application of the statute in 

an enforcement action. Such was the case in the State Farm case cited by the commenters. In that 

case, a court had awarded punitive damages of $145 million in addition to $1 million 

compensatory damages in an automobile liability case. A statutory penalty provision was not at 

 

56 See 538 U.S. 408, 417 (2003). 
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issue in that case and thus there were no statutory criteria for the lower court to consider in 

determining the appropriate penalty amount. Rather, in its review of whether the punitive 

damage award was excessive, and thus violated due process, the Court looked at three factors it 

has instructed lower courts to consider in assessing punitive damages. Such would be the case 

with any claim that a CAA penalty violated due process, where a reviewing court would consider 

whether the court appropriately considered the relevant penalty factors in assessing a penalty 

claimed as unconstitutional “as applied.” 

30. Comments that the EPA’s action eliminating affirmative defense provisions from SIPs 

violates the Eighth Amendment of the Constitution. 

Comment: Several commenters asserted that relying on judicial discretion to determine 

the appropriateness of penalties is arguably unconstitutional under the Eighth Amendment’s 

prohibition on excessive fines and punishments by allowing potentially significant penalties that 

are disproportionate to the offense. The commenter stated that an affirmative defense provision 

“helps guard against infringement of the Eighth Amendment’s protections.” Other commenters 

argued that the U.S. Supreme Court has held that Eighth Amendment protections apply to 

government action in a civil context as well as in a criminal context. The commenters claimed 

that significant penalties are not proportional to an offense caused by unavoidable events, such as 

excess emissions during malfunction events. The commenters concluded that unless the EPA 

allows states to accommodate unavoidable emissions through changes to applicable emission 

limitations before affirmative defenses are removed, the EPA’s proposal would “run afoul of 

Constitutional limitations.” 

One commenter stated that an affirmative defense is the “minimum protection EPA or the 

state must provide to avoid infringing constitutional rights.” The commenter also argued that the 
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EPA itself has relied on the existence of an affirmative defense to defend against a challenge to 

the achievability of an emission limitation in a FIP. To support this argument, the commenter 

quoted from the court’s opinion in Montana Sulphur.

57

Response: For the reasons provided above regarding commenters’ due process claims, the 

EPA also disagrees with their claims that eliminating affirmative defense provisions in SIPs 

would result in the penalty provisions of the CAA being facially in violation of the Eighth 

Amendment. Similarly, if a party believes that the penalties assessed in any civil enforcement 

action do violate the Eighth Amendment, they can raise a challenge that the specific SIP 

provision at issue “as applied” in that instance violates the U.S. Constitution. As with the 

commenters’ due process arguments, the EPA believes that Congress has already adequately 

addressed their concerns about potential unfair punishment for violations by authorizing courts to 

consider a range of factors in determining what remedies to impose for a particular violation, 

including the explicit factors for consideration in imposition of civil penalties as well as other 

factors as justice may require. 

The EPA acknowledges that is has previously relied on affirmative defense provisions as 

a mechanism to mitigate penalties where a violation was beyond the control of the owner or 

operator. These actions, however, predated the court’s decision in NRDC v. EPA and the EPA is 

now reevaluating its approach to affirmative defense provisions in its own rulemaking actions. In 

addition, the EPA believes that the penalty criteria in section 113(e) provide a similar function 

and the commenters do not explain why they believe these explicit statutory factors do not 

provide sufficient relief from the imposition of an allegedly unconstitutionally excessive penalty. 

 

57 See 666 F.3d at 1192–93 (“EPA acknowledges that violations are likely inevitable, but relies 

on the provision of an affirmative defense to compensate for infeasibility problems.”) 
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31. Comments that the EPA should impose a deadline of 12 months for states to respond to 

this SIP call with respect to affirmative defense provisions. 

Comment: An environmental organization commented that the EPA should require 

affected states to make the required SIP revisions within 12 months, rather than the 18 months 

proposed in the February 2013 proposal and the SNPR. The commenter claimed that 

communities near large sources have been suffering for decades and individuals are suffering 

adverse health effects because of the emissions from sources that are currently allowed by 

deficient SIP provisions. The commenter also stated that the EPA has recognized that excess 

emissions allowed by the SIP provisions subject to the SIP call are continuing to interfere with 

attainment and maintenance of the NAAQS and that this justifies imposing a shorter schedule for 

states to respond to the SIP call. 

Response: The EPA understands the concerns expressed by the commenters. However, as 

explained in the February 2013 proposal, the EPA believes that providing states with the full 18 

months authorized by section 110(k)(5) is appropriate in this action. The EPA is taking into 

consideration that state rule development and the associated administrative processes can be 

complex and time-consuming. This is particularly true where states might elect to consider more 

substantial revision of a SIP emission limitation, rather than merely removal of the impermissible 

automatic or discretionary exemption or the impermissible affirmative defense provision. In 

addition, the EPA believes that providing states with the full 18 months will be more likely to 

result in timely SIP submissions that will meet CAA requirements and provide the ultimate 

outcome that the commenters seek. Some states subject to the SIP call may be able to revise their 

deficient SIP provisions more quickly, and the EPA is committed to working with states to revise 

these provisions consistent with CAA requirements in a timely fashion. For these reasons, the 
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EPA does not agree that it would be reasonable to provide less than the 18-month maximum 

period allowed under the CAA for states to submit SIP revisions in response to the SIP call. 

32. Comments that the EPA should encourage states to add reporting and notification 

provisions into their SIPs. 

Comment: A commenter urged the EPA to encourage states to make information about 

excess emissions events easily and quickly accessible to the public. The commenter claimed that 

it is unacceptable to make it difficult for members of the public to obtain information about 

potential harmful exposure to pollutants and that state “open-record” request laws are 

inadequate, particularly when the public is not informed that an event occurred. The commenter 

also asserted that reporting provisions enhance compliance and cited to the Toxic Release 

Inventory program’s success in driving pollution reduction. The commenter argued that 

contemporaneous reporting of the conditions surrounding a violation, the cause and the measures 

taken to limit or prevent emissions ensure that stakeholders can respond in real time and also 

target enforcement efforts to violations where further action is warranted. As support for this 

approach, the commenter pointed to Jefferson County, Kentucky, as a local air quality control 

area that has already corrected problematic regulations in advance of this SIP call and also noted 

that the County included notification and reporting requirements, recognizing that they would 

reduce the burden on the government in trying to calculate the level of excess emissions and also 

help in responding to citizen inquiries about such events. 

Response: The EPA agrees with the commenter that reporting and notification provisions 

can ease the burden on government agencies by placing the burden on the entity that is in the 

best position to calculate the level of excess emissions and also provide other relevant 

information regarding such events. In addition, making this information available to the public 
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quickly allows for a timely response if there is any health concern. An increased level of 

communication between industry and residents also serves to build a better community 

relationship and partnership. The EPA also supports such requirements as components of SIP 

emission limitations because they facilitate effective compliance assurance. However, the EPA 

does not believe that the Agency should create a separate federal requirement addressing this 

issue beyond general CAA requirements at this time. 

33. Comments that this SIP call action concerning affirmative defense provisions is being 

taken pursuant to sue-and-settle tactics. 

Comment: One commenter alleged that the action proposed in the EPA’s SNPR has an 

“impermissible sue-and-settle genesis” and that the EPA is attempting to grant as much of Sierra 

Club’s petition as it can “regardless of the wisdom or permissibility of doing so.” 

Response: The EPA disagrees with the commenter’s allegation that the EPA’s proposed 

action in the SNPR is inappropriate because it is the result of “sue-and-settle” actions. This is a 

rulemaking in which the EPA is taking action to respond to a petition for rulemaking, and it has 

undergone a full notice-and-comment rulemaking process as provided for in the CAA. This issue 

is addressed in more detail in section V.D.1 of this document. 

34. Comments that affirmative defense provisions do not alter or eliminate federal court 

jurisdiction and therefore do not violate CAA sections 113 or 304. 

Comment: Two commenters argued that SIP affirmative defense provisions do not in fact 

interfere with the rights of litigants to pursue enforcement consistent with their rights under the 

citizen suit provision of CAA section 304 because plaintiffs have the right to bring a citizen suit 

despite the existence of affirmative defense provisions. One commenter cited at least four 

instances in the last few years in which environmental groups filed enforcement actions against 
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sources in federal district court based on alleged emissions events for which the companies 

asserted affirmative defenses. The commenters stated that courts applied the affirmative defense 

provision criteria and the criteria of section 113(e) to determine whether penalties were 

appropriate for alleged violations and did not dismiss plaintiffs’ claims for lack of jurisdiction. 

According to the commenters, affirmative defense provisions place additional burden on the 

sources, not plaintiffs, to demonstrate that the criteria of an affirmative defense are met. 

Response: The commenters argued that affirmative defense provisions are not 

inconsistent with the statutory requirements of section 304 because citizen groups still bring 

enforcement actions for events where companies may raise an affirmative defense. Even if this 

were so, the EPA disagrees with the commenters that this establishes that affirmative defense 

provisions are consistent with CAA requirements. The mere existence of enforcement actions 

does not negate the fact that affirmative defense provisions interfere with effective enforcement 

of SIP emission limitations according to CAA section 304. More to the point, affirmative defense 

provisions purport to alter or eliminate the statutory jurisdiction of courts to determine liability or 

to impose remedies for violations, which makes the provisions inconsistent with the grant of 

authority in sections 113 and 304. The courts’ decision in NRDC v. EPA was not based on the 

question of whether or not plaintiffs could still try to bring an enforcement case for violations of 

the EPA regulation at issue; the case was decided on the grounds that the EPA has no authority 

to limit or eliminate the jurisdiction of the courts. As explained in the SNPR and this notice, the 

EPA believes that the same principle applies to states in SIP provisions. 

35. Comments that this action may increase the chance of catastrophic failure at facilities. 

Comment: One commenter expressed a concern that eliminating affirmative defense 

provisions applicable to emissions during SSM events could increase the potential for 
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environmental harm caused by catastrophic failure by outlawing and penalizing the emissions 

during SSM events that have previously been allowed or shielded from liability through 

affirmative defense provisions. As an example, the commenter argued that refineries and gas 

plants must be allowed to vent VOCs to the atmosphere on the rare occasion that there is an 

equipment malfunction that could otherwise cause an explosion that might destroy the plant and 

surrounding neighborhood. The commenter speculated that the threat of costly new fines 

inherent with the removal of affirmative defense provisions could cloud plant operators’ thinking 

when they make safety decisions. The commenter contended that allowing rare, safely controlled 

releases of emissions would invariably be better for both the natural and human environment 

than the damage from a catastrophic explosion. 

Response: Although the comment refers to SSM events generally, the only specific 

concern raised by the commenter concerning affirmative defense provisions is that if they are not 

allowed in SIPs, this may lead to an increase in malfunction-related catastrophic events. The 

EPA does not agree with the commenter’s view that removal of affirmative defense provisions 

may increase environmental harm related to catastrophic events. The EPA believes that it is 

unlikely the availability or unavailability of an affirmative defense will affect a responsible and 

competent source operator’s response to a risk of explosion. First, an explosion presents much 

more serious and more certain adverse economic consequences for the source than does the 

specter of a potential enforcement action for a CAA violation, especially because enforcement 

agencies and courts are likely to exercise leniency if the violation was the result of an 

unpreventable malfunction. Second, even if an affirmative defense were available, it is only used 

after initiation of an enforcement proceeding and successful assertion of such a defense in an 

enforcement proceeding depends on meeting all affirmative defense criteria and is not 
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guaranteed. The EPA does not believe that a responsible and competent source operator’s actions 

in an emergency situation would be influenced by speculation that if the source is subject to an 

enforcement action in the future, there may be a defense to penalties available. 

Moreover, as explained in detail in the SNPR and this notice, the court’s decision in 

NRDC v. EPA held that section 113 and section 304 preclude EPA authority to create affirmative 

defense provisions in the Agency’s own regulations imposing emission limitations on sources, 

because such provisions purport to alter the jurisdiction of federal courts to assess liability and 

impose penalties for violations of those limits in private civil enforcement cases. The EPA 

believes that the reasoning of the court in that decision indicates that the states, like the EPA, 

have no authority in SIP provisions to alter the jurisdiction of federal courts to assess penalties 

for violations of CAA requirements through affirmative defense provisions. If states lack 

authority under the CAA to alter the jurisdiction of the federal courts through affirmative defense 

provisions in SIPs, then the EPA lacks authority to approve any such provision in a SIP. The 

EPA notes that the court in NRDC v. EPA did not indicate that the statutory provisions should be 

interpreted differently based on speculation that a given source operator might allow a 

catastrophic explosion because of the absence of an affirmative defense. 

36. Comments that the SNPR did not meet the procedural requirements of section 307(d) 

because the EPA failed to provide its legal interpretations or explain the data relied upon in this 

rulemaking. 

Comment: Commenters claimed that the EPA violated the procedural requirements of the 

CAA in the SNPR. The commenters asserted that the EPA designated this rulemaking a section 

307(d) rule, and the commenters claimed that the EPA did not follow the procedures required in 

section 307(d). The commenters claimed that the EPA failed to provide a statement of basis and 
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purpose that includes “the major legal interpretations and policy consideration underlying the 

proposed rule.” 

In particular, the commenters argued that the EPA did not provide required information 

with regard to its proposed SIP call concerning the affirmative defense provisions in the Texas 

SIP. Commenters claimed that the SNPR is deficient because it does not address: (i) why the 

Fifth Circuit decision in Luminant Generation v. EPA does not control the present action; (ii) on 

what basis the EPA believes it may disregard the judgment in Luminant Generation v. EPA; (iii) 

why the D.C. Circuit decision, which does not address the Texas SIP, should take precedence 

over the Luminant Generation v. EPA decision; (iv) on what basis the EPA believes that the D.C. 

Circuit may reach a different result than the Fifth Circuit as to the affirmative defenses in the 

Texas SIP; and (v) the grounds for “acquiescing” to the D.C. Circuit decision in NRDC v. EPA, 

which specifically states that it does not apply to SIP revisions, and ignoring the relevant holding 

in the Fifth Circuit. Commenters cited several cases claiming that the D.C. Circuit has held that, 

unlike under the Administrative Procedure Act (APA), under CAA section 307(d) the EPA is 

required to give a detailed explanation of its reasoning and that commenters should not be 

required to “divine the agency’s unspoken thoughts.” 

Response: The EPA disagrees with the commenters’ premise. The EPA did discuss the 

Luminant Generation v. EPA decision in the SNPR and also explained in detail why it believes 

that the logic of the D.C. Circuit’s decision in NRDC v. EPA supports this SIP call action for 

affirmative defense provisions. Specifically, the EPA recognized that both the Fifth Circuit and 

the D.C. Circuit were evaluating the same fundamental question—whether section 113 and 

section 304 preclude the creation of affirmative defense provisions that alter or eliminate the 

jurisdiction of federal courts to determine liability and impose remedies for violations of CAA 
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requirements in judicial enforcement actions. The EPA explained that, after reviewing the NRDC 

v. EPA decision and the Luminant Generation v. EPA decision, the Agency determined that its 

prior interpretation of the CAA, as advanced in both courts, is not the best reading of the statute. 

Indeed, it is significant that the Luminant court upheld the EPA’s approval of affirmative defense 

provisions for unplanned events (i.e., malfunctions) and the disapproval of affirmative defenses 

for planned events (i.e., startup, shutdown and maintenance) specifically because the court 

deferred to the Agency’s reasonable interpretation of ambiguous statutory provisions in the case 

at hand. In the SNPR, the EPA explained point by point why it now believes that the decision of 

the D.C. Circuit in NRDC v. EPA reflected the better reading of section 113 and section 304 and 

thus that the Agency no longer interprets the CAA to permit affirmative defenses in SIP 

provisions. Therefore, the EPA believes the Fifth Circuit could also take a different view of the 

reasonableness of the EPA’s resolution of ambiguous provisions after reviewing the EPA’s 

current interpretation of the statute. 

37. Comments that the EPA has recently approved affirmative defense provisions through 

various SIP actions and therefore, these provisions are proper under the EPA’s interpretation of 

the CAA. 

Comment: One commenter noted that the EPA has never taken issue with the affirmative 

defense provisions in states’ SIPs across the many instances where the EPA has reviewed the 

states’ later SIP submissions. The implication of the commenters’ argument is that if the EPA 

has previously approved a SIP submission and directly or indirectly reapproved an affirmative 

defense provision in the past, this means that the affirmative defense provision still meets CAA 

requirements. 
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Response: The EPA disagrees with this comment. As explained in the EPA’s response in 

section VIII.D.18 of this document, when the EPA takes final action on a state’s SIP submission, 

this does not necessarily entail reexamination and reapproval of every provision in the SIP. The 

EPA often only examines the specific SIP provision the state seeks to revise in the SIP 

submission, which may not include any affirmative defense provisions. To the extent the EPA 

did review and approve any affirmative defense provision consistent with its prior interpretation 

of the CAA that narrowly tailored affirmative defenses were appropriate, the EPA has fully 

explained why it is now revising that interpretation such that past action based on the earlier 

interpretation would no longer provide precedent for the EPA’s actions. Since the issuance of the 

court’s opinion in NRDC v. EPA, the EPA has been taking actions to address affirmative defense 

provisions in its own regulations and is doing so with respect to those in state SIPs in this action. 

The EPA acknowledges that it will take time for states and the Agency to revise existing 

regulations to eliminate affirmative defense provisions that were previously believed to be 

permissible. 

38. Comments that affirmative defense provisions function as structured state “enforcement 

discretion” and are an important tool for states to prioritize enforcement activities. 

Comment: A state commenter characterized the affirmative defense contained in the 

state’s SIP as an “enforcement discretion” tool that supports the state’s regulation of excess 

emissions during malfunction events and promotes preventive measures, proper monitoring and 

reporting by sources. The state asserted that removal of the affirmative defense provision from 

the SIP would require it to address and track violations that are not a high priority to the state 

agency. The state argued that the affirmative defense provision provides certainty to the 

regulated community by providing structure to how the state will exercise its enforcement 
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discretion. The state expressed concern that without the affirmative defense, there will be 

uncertainty for the regulated community and less incentive for sources to make repairs and 

submit excess emissions reports promptly. The commenter explained that state law requires 

reporting of emission events that exceed an established “reportable” quantity and that this 

prompt reporting allows the state agency to evaluate each event reported quickly. In investigating 

reports of emission events, the state claims that it “exercises enforcement discretion only in cases 

in which it determines that each affirmative defense criteria is met” and claimed that elimination 

of the affirmative defense provision would result in an increase of unavoidable emissions being 

treated as violations. In general, the state objected to the elimination of the affirmative defense 

provision because it would strain the state agency’s enforcement resources. 

Response: These comments concerning the state’s use of affirmative defense criteria in 

structuring the exercise of its enforcement discretion (e.g., determining whether to bring an 

enforcement action or to further investigate an emissions events) appear to be based on a 

misunderstanding of the EPA’s SNPR. This SIP call action directing states to remove affirmative 

defense provisions from SIPs would not prevent the state from applying such criteria in the 

exercise of its own enforcement discretion. For example, the state is free to consider factors such 

as a facility’s efforts to comply, compliance history and other factors in determining whether to 

investigate an excess emissions event or whether to issue a notice of violation or otherwise 

pursue enforcement. Application of such criteria may well be useful and appropriate to the state 

in determining the best way to allocate its own enforcement resources. So long as a state does not 

use the criteria in such a way that the state fails to have a valid enforcement program as required 

by section 110(a)(2)(C), the state is free to use criteria like those of an affirmative defense as a 

way to “structure” its exercise of its own enforcement discretion. 
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However, as explained in the SNPR, the EPA’s view is that SIPs cannot include 

affirmative defense provisions that alter the jurisdiction of the federal court to assess penalties in 

judicial enforcement proceeding for violation of CAA requirements. In addition, the EPA 

interprets the CAA to bar “enforcement discretion” provisions in SIPs that operate to impose the 

enforcement discretion decisions of the state upon the EPA or any other parties who may seek to 

enforce pursuant to section 304. The EPA has determined that the specific affirmative defense 

provisions at issue in the SIP of the state commenter are inconsistent with CAA requirements for 

SIP provisions. In addition, the EPA interprets the CAA to bar “enforcement discretion” 

provisions in SIPs that operate to impose the enforcement discretion decisions of the state upon 

the EPA or any other parties who may seek to enforce pursuant to section 304. Pursuant to the 

requirements of sections 110(k), 110(l) and 193, the EPA has both the authority and the 

responsibility to evaluate SIP submissions to assure that they meet the requirements of the CAA. 

Pursuant to section 110(k)(5), the EPA has authority and discretion to take action to require 

states to revise previously approved SIP provisions if they do not meet CAA requirements. 

39. Comments that requiring states to adopt emissions standards that are not achievable at all 

times and then expecting courts to render those standards lawful by employing discretion in the 

assessment of penalties is contradictory to CAA section 307(b)(2), which mandates preenforcement review. 

Comment: Commenters claimed that courts have consistently held that regulators cannot 

rely on enforcement discretion to establish the achievability of emission limitations. The 

commenters referred to a 1973 case addressing New Source Performance Standards (NSPS) in 

which they claimed the court remanded the standard to the EPA to support an “at all times” 

standard. 
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Commenters further asserted that reliance on the discretion of judges to decide whether 

and to what extent penalties are appropriate is also not lawful. The commenters claimed that if a 

state establishes an emission limitation on the basis that it is achievable, then the standard must 

be achievable under all circumstances to which they apply. The commenters argued that if a state 

adopts an emission limitation that is not achievable under all conditions, then the state must 

explain how the standard can be reasonably enforced. The commenters concluded that a 

numerical emission limitation that cannot be achieved by sources at all times is not enforceable 

because no amount of penalty can deter the violating conduct. The commenters recognized that it 

is reasonable for states to exercise enforcement discretion under circumstances an emission 

limitation cannot be met but argued that it is not reasonable to adopt a SIP that puts sources in a 

state of repeated noncompliance. 

Commenters further claimed that the decision in NRDC v. EPA, while allowing sources 

to argue unjust punishment should not be imposed, conflicts with the CAA’s requirements for 

pre-enforcement review. The commenters stated that emission limitations that could have been 

challenged at the time of promulgation are not subject to judicial review in an enforcement 

proceeding. Thus, the commenters claimed that any challenges to the achievability of a SIP 

emission limitation must be made at the time the emission limitation is promulgated and that 

judges will not consider such arguments in the context of an enforcement action. The 

commenters argued that forcing states to adopt unachievable standards and then prohibiting them 

from including an affirmative defense for penalties for unavoidable exceedances creates a 

dilemma Congress sought to avoid. 

Response: It appears that a number of the arguments that the commenters are raising go 

beyond the scope of the affirmative defense issues in the SNPR. In the SNPR, the EPA revised 
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its prior proposal with respect to issues related exclusively to affirmative defense provisions in 

SIPs. These comments are similar to an argument that any period during which an emission 

limitation cannot be met must be deemed not to be a violation of the standard. The EPA is 

addressing these types of comments, to the extent that they were raised, in its response to 

comments on the February 2013 proposal. The EPA does note, however, that the Agency is not 

requiring states to adopt standards that cannot be met and then providing that states rely only on 

enforcement discretion to address periods of noncompliance. As the EPA has already noted, 

states may choose to adopt standards that are different from the underlying standards for periods 

where the underlying standards cannot otherwise be met. 

The EPA also disagrees with the comments that the holding in NRDC v. EPA is 

inconsistent with section 307(b)(2) that provides that regulations that could have been challenged 

at promulgation cannot later be challenged in an enforcement action. Nothing in section 307(b) 

limits the ability of the court to consider the criteria of section 113(e), such as good faith efforts 

of a source to comply in assessing penalties. Neither the decision in NRDC v. EPA nor this SIP 

call action requires states to adopt standards that cannot be met. Moreover, the public, including 

regulated sources, will be able to comment on the revised emission limitations developed by 

states in response to this SIP call. If an interested party believes that the state has adopted 

unachievable emission limitations, they can challenge such standards at the time of adoption. 

40. Comments that the EPA should announce that it no longer recognizes existing affirmative 

defense provisions, effective immediately. 

Comment: Commenters claimed that because the court held in NRDC v. EPA that the 

EPA was without authority to interpret the CAA to allow affirmative defenses, the EPA should 

explicitly state that it no longer recognizes such provisions immediately. The commenters argued 
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that by proceeding under its authority under section 110(k)(5), the EPA is providing states 18 

months to remove the affirmative defense provisions and that thereafter the EPA will take 

additional time to act upon those SIP revisions under section 110(k). The commenters argued 

that this in effect allows sources to continue relying on affirmative defense provisions that are 

not consistent with CAA requirements for a period of years into the future. Because the EPA did 

not have authority to approve the affirmative defense provisions in the first instance, the 

commenters contended that the Agency should simply declare that the affirmative defense 

provisions are now null and void. 

Response: The EPA understands the concerns raised by the commenters but does not 

agree that it is inappropriate for the Agency to proceed under section 110(k)(5). The affirmative 

defense provisions at issue in this action are part of the EPA-approved SIPs for the affected 

states. The EPA, as well as states, cannot unilaterally change provisions of the approved SIP 

without following appropriate notice-and-comment procedures. To the extent that the 

commenters were advocating that the EPA should have proceeded under its authority to do error 

corrections under section 110(k)(6) rather than a SIP call under section 110(k)(5), the Agency 

has explained in detail in the February 2013 proposal and this notice why it is more appropriate 

to proceed via SIP call instead. Under the SIP call process, the EPA cannot declare approved SIP 

provisions null and void prior to state submission and Agency approval of revised SIP 

provisions. 

41. Comments that instead of acting through a nationwide SIP call action, the EPA should 

have worked individually with states to correct any deficient SIP provisions. 

Comment: One commenter stated that rather than using a SIP call to address SSM issues 

in existing SIPs, the EPA should work with each state’s air agency individually to identify and 
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address SIP deficiencies and work through the normal rulemaking and SIP revision processes to 

correct any identified problems. 

Response: The CAA provides a mechanism specifically for the correction of flawed SIPs. 

Section 110(k)(5) provides: “Whenever the Administrator finds that the applicable 

implementation plan for any area is substantially inadequate to ... comply with any requirement 

of [the Act], the Administrator shall require the State to revise the plan as necessary to correct 

such inadequacies.” This type of action is commonly referred to as a “SIP call.” The EPA, in this 

action, is using a SIP call to notify states of flawed provisions in SIPs and initiate a process for 

correction of those provisions. 

The EPA, largely through its Regional Offices, has individually reviewed each state 

provision subject to the SIP call. The EPA will work closely with each state, during future 

rulemaking actions taken by states to adopt SIP revisions and then subsequent actions by the 

EPA, to determine whether these adopted SIP revisions meet the mandate of the SIP call and are 

consistent with CAA requirements. As part of these actions, each individual state will work 

closely with the EPA to address the SIP deficiencies identified in this action. 

42. Comments that the EPA should not consider the comments on the February 2013 

proposal concerning affirmative defense provisions in SIPs to no longer be relevant. 

Comment: One commenter disagreed with the EPA’s decision not to respond to 

comments submitted on the February 2013 proposal to the extent the comments applied to issues 

related to affirmative defense provisions in SIPs generally, or to issues related to specific 

affirmative defense provisions identified by the Petitioner because those comments will no 

longer be relevant if the EPA finalizes its action as proposed in the SNPR. The commenter stated 

that the EPA’s interpretation of the CAA has not changed so as to exclude the previous SSM 
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provisions in the proposed rule, and this alone shows that the comments submitted on the 

February 2013 proposal are still relevant. 

Response: The EPA’s proposed action on the Petition in the SNPR superseded the 

February 2013 proposal with respect to the issues related to affirmative defense provisions in 

SIPs. As explained in detail in the SNPR, after the February 2013 proposal, a federal court ruled 

that the CAA precludes authority of the EPA to create affirmative defense provisions applicable 

to private civil suits in its own regulations. As a result, the EPA issued the SNPR to propose 

applying a revised interpretation of the CAA to affirmative defense provisions in SIPs consistent 

with the reasoning of court’s decision in NRDC v. EPA. The EPA supplemented and revised its 

proposed response to the issues raised in the Petition to the extent they concern affirmative 

defenses in SIPs, and the EPA solicited comment on its revised proposed response. Because the 

EPA’s interpretation of the CAA with respect to the legal basis for affirmative defense 

provisions in SIPs changed from the time of the February 2013 proposal to the SNPR, comments 

on the February 2013 proposal are no longer relevant to the EPA’s revised proposed action. For 

example, previous comments arguing that the EPA was wrong to interpret the CAA to allow 

affirmative defense provisions for malfunction events but not for startup or shutdown events are 

not relevant if the Agency’s interpretation of the CAA is that no such affirmative defense 

provisions are valid. Similarly, comments that the criteria that the EPA previously recommended 

for valid affirmative defense provisions were too many, too few, too stringent or too lax simply 

have no relevance when the EPA does not interpret the CAA to allow any such affirmative 

defense provisions regardless of the number, nature or stringency of the criteria for qualifying for 

the affirmative defense. The EPA believes that it is reasonable for the Agency to determine that 

comments that have no bearing on the proposed action concerning affirmative defense provisions 
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in the SNPR are not relevant. Because the EPA is finalizing the action on the Petition as 

proposed in the SNPR concerning affirmative defense provisions in SIPs, it did so based on 

evaluation of the comments that were relevant to the SNPR. 

V. Generally Applicable Aspects of the Final Action in Response to Request for the 

EPA’s Review of Specific Existing SIP Provisions for Consistency with CAA Requirements 

A. What the Petitioner Requested 

The Petitioner’s second request was for the EPA to find as a general matter that SIPs 

“containing an SSM exemption or a provision that could be interpreted to affect EPA or citizen 

enforcement are substantially inadequate to comply with the requirements of the Clean Air 

Act.”58 In addition, the Petitioner requested that if the EPA finds such defects in existing SIPs, 

the EPA “issue a call for each of the states with such a SIP to revise it in conformity with the 

requirements or otherwise remedy these defective SIPs.”59 

The Petitioner argued that many SIPs currently contain provisions that are inconsistent 

with the requirements of the CAA. According to the Petitioner, these provisions fall into two 

general categories: (1) exemptions for excess emissions by which such emissions are not treated 

as violations; and (2) enforcement discretion provisions that may be worded in such a way that a 

decision by the state not to enforce against a violation could be construed by a federal court to 

bar enforcement by the EPA under CAA section 113, or by citizens under CAA section 304. 

First, the Petitioner expressed concern that many SIPs have either automatic or 

discretionary exemptions for excess emissions that occur during periods of SSM. Automatic 

exemptions are those that, on the face of the SIP provision, provide that any excess emissions 

 

58 Petition at 14. 

59 Id. 
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during such events are not violations even though the source exceeds the otherwise applicable 

emission limitations. These provisions preclude enforcement by the state, the EPA or citizens, 

because by definition these excess emissions are defined as not violations. Discretionary 

exemptions or, more correctly, exemptions that may arise as a result of the exercise of “director’s 

discretion” by state officials, are exemptions from an otherwise applicable emission limitation 

that a state may grant on a case-by-case basis with or without any public process or approval by 

the EPA, but that do have the effect of barring enforcement by the EPA or citizens. The 

Petitioner argued that “[e]xemptions that may be granted by the state do not comply with the 

enforcement scheme of title I of the Act because they undermine enforcement by the EPA under 

section 113 of the Act or by citizens under section 304.” 

The Petitioner explained that all such exemptions are fundamentally at odds with the 

requirements of the CAA and with the EPA’s longstanding interpretation of the CAA with 

respect to excess emissions in SIPs. SIPs are required to include emission limitations designed to 

provide for the attainment and maintenance of the NAAQS and for protection of PSD 

increments. The Petitioner emphasized that the CAA requires that such emission limitations be 

“continuous” and that they be established at levels that achieve sufficient emissions control to 

meet the required CAA objectives when adhered to by sources. Instead, the Petitioner contended, 

exemptions for excess emissions through “loopholes” in SIP provisions often result in real-world 

emissions that are far higher than the level of emissions envisioned and planned for in the SIP. 

Second, the Petitioner expressed concern that many SIPs have provisions that may have 

been intended to govern only the exercise of enforcement discretion by the state’s own personnel 

but are worded in a way that could be construed to preclude enforcement by the EPA or citizens 

if the state elects not to enforce against the violation. The Petitioner contended that “any SIP 
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provision that purports to vest the determination of whether or not a violation of the SIP has 

occurred with the state enforcement authority is inconsistent with the enforcement provisions of 

the Act.” 

After articulating these overarching concerns with existing SIP provisions, the Petitioner 

requested that the EPA evaluate specific SIP provisions identified in the separate section of the 

Petition titled, “Analysis of Individual States’ SSM Provisions.”60 In that section, the Petitioner 

identified specific provisions in the SIPs of 39 states that the Petitioner believed to be 

inconsistent with the requirements of the CAA and explained in detail the basis for that belief. In 

the conclusion section of the Petition, the Petitioner listed the SIP provisions in each state for 

which it seeks a specific remedy. A more detailed explanation of the Petitioner’s arguments 

appears in the 2013 February proposal.61 

B. What the EPA Proposed 

In its February 2013 proposal, the EPA proposed to deny in part and to grant in part the 

Petition with respect to this two-part request. The EPA explained its longstanding interpretations 

of the CAA with respect to SIP provisions that apply to excess emissions during SSM events. 

The EPA also agreed that automatic exemptions, discretionary exemptions via director’s 

discretion, ambiguous enforcement discretion provisions that may be read to preclude EPA or 

citizen enforcement and affirmative defense provisions can interfere with the overarching 

objectives of the CAA, such as attaining and maintaining the NAAQS, protecting PSD 

increments and improving visibility. Such provisions in SIPs can interfere with effective 

enforcement by air agencies, the EPA and the public to assure that sources comply with CAA 

 

60 Petition at 17. 

61 See February 2013 proposal, 78 FR 12459 at 12473–74 (February 22, 2013). 
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requirements, and such interference is contrary to the fundamental enforcement structure 

provided in CAA sections 113 and 304. 

Accordingly, the EPA evaluated each of the specific SIP provisions that the Petitioner 

identified to determine whether it is consistent with CAA requirements for SIP provisions. The 

EPA conducted this evaluation in light of its interpretations of the CAA reflected in the SSM 

Policy and recent court decisions pertaining to relevant issues. In section IX of the February 

2013 proposal, the EPA provided its proposed view with respect to each of these SIP provisions. 

The EPA solicited comment on its proposed grant or denial of the Petition for each of the 

specific SIP provisions and its rationale for the proposed action. Through consideration of the 

overarching issues raised by the Petition, and informed by the evaluation of the specific SIP 

provisions identified in the Petition as a group, the EPA also determined that it was necessary to 

reiterate, clarify and amend its SSM Policy. The EPA thus took comment on its interpretations of 

the CAA set forth in the SSM Policy in order to assure that it provides comprehensive and 

updated guidance to states concerning SIP provisions applicable to emissions from sources 

during SSM events. 

C. What Is Being Finalized In This Action 

The EPA is taking final action to deny in part and to grant in part the Petition with respect 

to the request to find specific SIP provisions inconsistent with the CAA as interpreted by the 

Agency in the SSM Policy. The EPA is also taking final action to grant the Petition on the 

request to make a finding of substantial inadequacy and to issue a SIP call for specific existing 

SIP provisions. The basis for the SIP call is that these provisions include an automatic 

exemption, a discretionary exemption, an inappropriate enforcement discretion provision, an 

affirmative defense provision, or other form of provision that is inconsistent with CAA 
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requirements for SIP provisions. For those SIP provisions that the EPA has determined to be 

consistent with CAA requirements, however, the Agency is taking final action to deny the 

Petition and taking no further action with respect to those provisions. The specific SIP provisions 

at issue are discussed in detail in section IX of this document. 

As a result of its review of the issues raised by the Petition, the EPA is also through this 

action clarifying, reiterating and updating its SSM Policy to make certain that it provides 

comprehensive and up-to-date guidance to air agencies concerning SIP provisions to address 

emissions during SSM events, consistent with CAA requirements. With respect to automatic 

exemptions from emission limitations in SIPs, the EPA’s longstanding interpretation of the CAA 

is that such exemptions are impermissible because they are inconsistent with the fundamental 

requirements of the CAA. The EPA has reiterated this point in numerous guidance documents 

and rulemaking actions and is reconfirming that interpretation in this final action. By exempting 

emissions that would otherwise constitute violations of the applicable emission limitations, such 

exemptions interfere with the primary air quality objectives of the CAA (e.g., attainment and 

maintenance of the NAAQS), undermine the enforcement structure of the CAA (e.g., the 

requirement that all SIP provisions be legally and practically enforceable by states, the EPA and 

parties with standing under the citizen suit provision), and eliminate the incentive for emission 

sources to comply at all times, not solely during normal operation (e.g., incentives to be properly 

designed, maintained and operated so as to minimize emissions of air pollutants during startup 

and shutdown or to take prompt steps to rectify malfunctions). 

The court’s decision in Sierra Club v. EPA concerning exemptions for SSM events in the 

EPA’s own regulations has reemphasized the fact that emission limitations under the CAA are 

required to be continuous. The court held that this statutory requirement precludes emission 
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limitations that would allow periods during which emissions are exempt. Moreover, from a 

policy perspective, the EPA notes that the existence of impermissible exemptions in SIP 

provisions has the potential to lessen the incentive for development of control strategies that are 

effective at reducing emissions during certain modes of source operation such as startup and 

shutdown, even while such strategies could become increasingly helpful for various purposes, 

including attaining and maintaining the NAAQS. The issue of automatic exemptions for SSM 

events in SIP provisions is discussed in more detail in section VII.A of this document. 

With respect to discretionary exemptions from emission limitations in SIPs, the EPA also 

has a longstanding interpretation of the CAA that prohibits “director’s discretion” provisions in 

SIPs if they provide unbounded discretion to allow what would amount to a case-specific 

revision of the SIP without meeting the statutory requirements of the CAA for SIP revisions. In 

particular, the EPA interprets the CAA to preclude SIP provisions that provide director’s 

discretion authority to create discretionary exemptions for violations when the CAA would not 

allow such exemptions in the first instance. As with automatic exemptions for excess emissions 

during SSM events, discretionary exemptions for such emissions interfere with the primary air 

quality objectives of the CAA, undermine the enforcement structure of the CAA and eliminate 

the incentive for emission sources to minimize emissions of air pollutants at all times, not solely 

during normal operations. Through this action, the EPA is reiterating its interpretation of the 

provisions of the CAA that preclude unbounded director’s discretion provisions in SIPs. The 

EPA is also explaining two ways in which air agencies may elect to correct a director’s 

discretion deficiency. The issue of director’s discretion in SIP provisions applicable to SSM 

events is discussed in more detail in section VII.C of this document. 
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With respect to enforcement discretion provisions in SIPs, the EPA also has a 

longstanding interpretation of the CAA that SIPs may contain such provisions concerning the 

exercise of discretion by the air agency’s own personnel, but such provisions cannot bar 

enforcement by the EPA or by other parties through a citizen suit.62 In the event such a SIP 

provision could be construed by a court to preclude EPA or citizen enforcement, that provision 

would be at odds with fundamental requirements of the CAA pertaining to enforcement. Such 

provisions in SIPs can interfere with effective enforcement by the EPA and the public to assure 

that sources comply with CAA requirements, and this interference is contrary to the fundamental 

enforcement structure provided in CAA sections 113 and 304. The issue of enforcement 

discretion in SIP provisions applicable to SSM events is discussed in more detail in section 

VII.D of this notice. 

The EPA has evaluated the concerns expressed by the Petitioner with respect to each of 

the identified SIP provisions and has considered the specific remedy sought by the Petitioner. 

Through evaluation of comments on the February 2013 proposal and the SNPR, the EPA has 

taken into account the perspective of other stakeholders concerning the proper application of the 

CAA and the Agency’s preliminary evaluation of the specific SIP provisions identified in the 

Petition. In many instances, the EPA has concluded that the Petitioner’s analysis is correct and 

that the provision in question is inconsistent with CAA requirements for SIPs. For those SIP 

provisions, the EPA is granting the Petition and is simultaneously making a finding of substantial 

inadequacy and issuing a SIP call to the affected state to rectify the specific SIP inadequacy. In 

other instances, however, the EPA disagrees with the Petitioner’s analysis of the provision. For 

 

62 See, e.g., 1983 SSM Guidance at Attachment p. 2. 
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those provisions, the EPA is therefore denying the Petition and taking no further action. In 

summary, the EPA is granting the Petition in part, and denying the Petition in part, with respect 

to each of the specific existing SIP provisions for which the Petitioner requested a remedy. The 

EPA’s evaluation of each of the provisions identified in the Petition and the basis for the final 

action with respect to each provision is explained in detail in section IX of this document. 

D. Response to Comments Concerning the CAA Requirements for SIP Provisions Applicable 

to SSM Events 

The EPA received numerous comments, both supportive and adverse, concerning the 

Agency’s decision to propose action on the Petition with respect to the overarching issues raised 

by the Petitioner. A number of these comments raised important issues concerning the rights of 

citizens to petition their government, the process by which the EPA evaluated the issues raised in 

the Petition and the relative authorities and responsibilities of states and the EPA under the CAA. 

Many commenters raised the same conceptual issues and arguments concerning the EPA’s 

approach. For clarity and ease of discussion, the EPA is responding to these overarching 

comments, grouped by topic, in this section of this notice. The responses to more specific 

substantive issues raised by commenters on the EPA’s interpretation of the CAA in the SSM 

Policy appear in other sections of this notice that focus on particular aspects of this action. 

1. Comments that the EPA should not have responded to the petition for rulemaking or that 

the EPA was wrong to do so. 

Comment: Some commenters opposed the EPA’s proposed action on the Petition in the 

February 2013 proposal entirely and alleged that it is “sue and settle rulemaking” or “regulationby-litigation.” Commenters stated that the “proposed rule and corresponding aggressive deadline 

schedule stem from” a settlement of litigation brought by Sierra Club to respond to the Petition. 
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The commenters expressed concern that the EPA’s proposed action was made in response 

to a settlement agreement, which the commenters alleged did not permit any opportunity for 

participation by affected parties. The commenters argued that consent decree deadlines “often do 

not allow EPA enough time to write quality regulations” or would not allow “opportunity to 

properly research and investigate the effect of State SSM provisions or the State’s ability to meet 

the NAAQS, or to determine whether the SSM provisions are somehow inconsistent with the 

CAA.” Commenters further alleged that because the EPA’s proposed action was taken to fulfill a 

consent decree obligation, the process “bypasses the traditional rulemaking concepts of 

transparency and effective public participation” and “sidesteps the proper rulemaking channels 

and undercuts meaningful opportunities for those affected by the proposed rule to develop and 

present evidence that would support a competing and fully informed viewpoint on the 

substantive issues during the rulemaking process.” 

Response: The EPA believes that these comments reflect fundamental misunderstandings 

about this action. This is a rulemaking in which the EPA is taking action to respond to a petition 

for rulemaking, and it has undergone a full notice-and-comment rulemaking process as provided 

for in the CAA. In the February 2013 proposal, the EPA proposed to take action on the Petition. 

Under the CAA, the APA and the U.S. Constitution, citizens have the right to petition the 

government for redress. For example, the APA provides that “[e]ach agency shall give an 

interested person the right to petition for the issuance, amendment, or repeal of a rule.”63 When 

citizens file a petition for rulemaking, they are entitled to a response to such petition—whether 

 

63 5 U.S.C. 553(e). 
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that response is to grant the petition, to deny the petition, or to partially grant and partially deny 

the petition as has occurred in this rulemaking action. 

Some of these commenters expressed concern that the EPA’s action on the Petition was 

the result of the Agency’s obligations under a consent decree or settlement agreement and that 

this fact in some way invalidates the substantive action. First, the EPA notes that the action was 

undertaken in response not to a consent decree, but rather in response to a settlement agreement. 

Second, the EPA notes that this settlement agreement was entered into by the Agency and the 

Sierra Club in order to resolve allegations that the EPA was not correctly evaluating and acting 

upon SIP submissions from states. In particular, the Sierra Club claimed that the EPA was 

illegally ignoring existing deficiencies in the SIPs of many states, including existing allegedly 

deficient provisions concerning the treatment of excess emissions during SSM events, when 

acting on certain SIP submissions. As a result, the Sierra Club alleged, the EPA was acting in 

contravention of its obligations under the CAA and various consent decrees and thus should be 

held in contempt for failure to address these issues. In order to resolve these allegations, the EPA 

agreed only to take action on a petition for rulemaking and to take the action that it deemed 

appropriate after evaluation of the allegations in the petition. The terms of the settlement 

agreement underwent public comment and are a matter of public record and are in the docket for 

this rulemaking.64 

 

64 See Settlement Agreement executed November 30, 2011, in the rulemaking docket at EPAHQ-OAR-2012-0322-0039. 
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The EPA does not enter into settlement agreements lightly, nor does the EPA enter into 

settlement agreements without following the full public process required by CAA section 113(g), 

which the Agency followed in this case.65 The EPA solicited comment on the draft settlement 

agreement as required by section 113(g). In no case does the EPA enter into a settlement 

agreement that has not been officially reviewed not only by the Agency but also by the 

Department of Justice. The commenters’ implications are that this rulemaking is the result of an 

inappropriate settlement agreement that did not undergo public comment or that was not 

legitimate. Those implications are in error. 

In acting on the Petition the EPA has followed all steps of a notice-and-comment 

rulemaking, as governed by applicable statutes, regulations and executive orders, including a 

robust process for public participation. When the EPA initially proposed to take action on the 

Petition, it simultaneously solicited public comment on its proposed response to all of the issues 

in the Petition and in particular on its proposed action with respect to each of the specific 

existing SIP provisions identified by the Petitioner as inconsistent with the requirements of the 

CAA. In response to requests, the EPA extended the public comment period for this proposal to 

May 13, 2013, which is 80 days from the date the proposed rulemaking was published in the 

Federal Register and 89 days from the date the proposed rulemaking was posted on the EPA’s 

website.66 The EPA deemed this extension appropriate because of the issues raised in the 

February 2013 proposal. The EPA also held a public hearing on March 12, 2013. In response to 

 

65 See “Proposed Settlement Agreement, Clean Air Act Citizen Suit” (notice of proposed 

settlement agreement; request for public comment), 76 FR 54465 (September 1, 2011). 

66 See “State Implementation Plans: Response to Petition for Rulemaking; Findings of 

Substantial Inadequacy; and SIP Calls To Amend Provisions Applying to Excess Emissions 

During Periods of Startup, Shutdown, and Malfunction; Extension of Comment Period,” 78 FR 

20855 (April 8, 2013), in the rulemaking docket at EPA-HQ-OAR-2012-0322-0126. 
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this proposed action, the EPA received approximately 69,000 public comments, including over 

50 comment letters from state and local governments, over 150 comment letters from industry 

commenters, over 25 comment letters from public interest groups and many thousands of 

comments from individual commenters. Many of these comment letters were substantial and 

covered numerous issues. 

Similarly, when the EPA ascertained that it was necessary to revise its proposed action on 

the Petition with respect to affirmative defenses in SIP provision, the Agency issued the SNPR. 

In that supplemental proposal, the EPA fully explained the issues and took comment on the 

questions related to whether affirmative defense provisions are consistent with CAA 

requirements concerning the jurisdiction of courts in enforcement actions, and thus whether such 

provisions are consistent with fundamental CAA requirements for SIP provisions. The EPA 

provided a public comment period ending November 6, 2014, which is 50 days from the date the 

SNPR was published in the Federal Register and 62 days from the date the SNPR was posted on 

the EPA’s website. The EPA believes that the comment period was sufficient given that the 

subject of the SNPR was limited to the narrow issue of whether affirmative defense provisions 

are consistent with CAA requirements. The EPA also held a public hearing on the SNPR on 

October 7, 2014 on the specific topic of the legitimacy of affirmative defense provisions in SIPs. 

In response to the SNPR, the EPA received over 20,000 public comments, including at least 9 

comment letters from states and local governments, over 40 comment letters from industry 

commenters, at least 6 comment letters from public interest groups, and many thousands of 

comments from individual commenters. 

2. Comments that EPA’s action on the Petition violates “cooperative federalism.” 
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Comment: Many commenters asserted that the EPA’s proposed action on the Petition and 

the issuance of this SIP call violate principles of cooperative federalism because they 

impermissibly substitute the EPA’s judgment for that of the states in the development of SIPs. 

This argument was raised by both air agency and industry commenters. 

These commenters described the relationship between states and the EPA with respect to 

SIPs in general. The commenters stated that Congress designed the CAA as a regulatory 

partnership between the EPA and the states, i.e., a relationship based on “cooperative 

federalism.” Under cooperative federalism, the commenters noted, the EPA has the primary 

responsibility to identify air pollutants that endanger the public health and welfare and to set 

national standards for those pollutants. By contrast, the states have primary responsibility to 

determine how to achieve those national standards by developing federally enforceable measures 

through SIPs. According to these commenters, however, once a state has made a SIP submission, 

the EPA’s role is relegated exclusively to the ministerial function of reviewing whether the SIP 

submission will result in compliance with the NAAQS. Similarly, the commenters claim that 

when EPA is evaluating in the context of a SIP call whether a state’s existing SIP continues to 

meet applicable CAA requirements, the only relevant question is whether the existing SIP will 

result in compliance with the NAAQS. Thus, the commenters claimed that by finding certain 

existing SIP provisions substantially inadequate because they are legally deficient to meet CAA 

requirements for SIP provisions, the EPA is usurping state authority under the cooperativefederalism structure of the CAA. 
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To support this view, many commenters cited to the “Train-Virginia line of cases,” 

named for the U.S. Supreme Court case Train v. Natural Resources Defense Council, Inc.,

67 and 

the D.C. Circuit case Commonwealth of Virginia v. EPA.

68 The D.C. Circuit has described these 

cases as defining a “federalism bar” that constrains the EPA’s authority with respect to 

evaluation of state SIPs under section 110.69 Many commenters asserted that this federalism bar 

limits the EPA’s oversight of state SIPs exclusively to whether a SIP will result in compliance 

with NAAQS. The commenters evidently construe “compliance with the NAAQS” very 

narrowly to mean whether the SIP will factually result in attainment of the NAAQS, regardless 

of whether the SIP provisions in fact meet all applicable CAA requirements (e.g., the 

requirement that the SIP emission limitations be continuous and enforceable). Accordingly, most 

of these commenters selectively quoted or cited a passage in Train,

70 and similar passages in 

circuit court opinions following Train, for the proposition that the EPA cannot issue a SIP call 

addressing the SIP provisions at issue in this SIP call action. Some of these commenters asserted 

that if the EPA were to finalize this action, the states would have “nothing left” of their 

discretion in SIP development and implementation in the future. 

Response: The EPA agrees that the CAA establishes a framework for state-federal 

partnership based on cooperative federalism. The EPA does not, however, agree with the 

 

67 421 U.S. 60 (1975). 

68 108 F.3d 1397 (D.C. Cir. 1997). 

69 See, e.g., Michigan v. EPA, 213 F.3d 663, 687 (D.C. Cir. 2000). 

70 See 421 U.S. at 79. 
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commenters’ characterization of that relationship. The EPA explained its view of the 

cooperative-federalism structure in the February 2013 proposal, especially the fact that under this 

principle both states and the EPA have authorities and responsibilities with respect to 

implementing the requirements of the CAA.71 The EPA believes that the commenters 

fundamentally misunderstand or inaccurately describe this action, as well as the “‘division of 

responsibilities’ between the states and the federal government” in section 110 that is described 

in the Train-Virginia line of cases.72 

In section 110(a)(1) Congress imposed the duty upon all states to have a SIP that 

provides for “the implementation, maintenance, and enforcement” of the NAAQS. In section 

110(a)(2), Congress clearly set forth the basic SIP requirements that “[e]ach such plan shall” 

satisfy.73 By using the mandatory “shall” in section 110(a)(2), Congress established a framework 

of mandatory requirements within which states may exercise their otherwise considerable 

discretion to design SIPs to provide for attainment and maintenance of the NAAQS and to meet 

other CAA requirements. In other sections of the Act, Congress also imposed additional, more 

specific SIP requirements (e.g., the requirement in section 189 that states impose RACM-level 

emission limitations on sources located in PM2.5 nonattainment areas). 

In particular, this SIP call action concerns whether SIP provisions satisfy section 

110(a)(2)(A), which requires that each SIP “shall”: 

include enforceable emission limitations and other control measures, means, or 

techniques (including economic incentives such as fees, marketable permits, and 

 

71 See 78 FR 12459 at 12468; Background Memorandum at 1–3. 

72 See Virginia v. EPA, 108 F.3d 1397, 1407 (D.C. Cir. 1997) (quoting Train, 421 U.S. at 79). 

73 Section 110(a)(2) (emphasis added); see EPA v. EME Homer City Generation, L.P., 134 S. Ct. 

1584, 1600 (2014) (holding that section 110(a)(2) “speaks without reservation” regarding what 

“components” a SIP “‘shall’ include”) H. Rept. 101-490, at 217 (calling the provisions of section 

110(a)(2)(A) through (M) “the basic requirements of SIPs”). 
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auctions of emissions rights), as well as schedules and timetables for compliance, 

as may be necessary or appropriate to meet the applicable requirements of this 

chapter[.] 

As explained in the February 2013 proposal, the automatic and discretionary exemptions for 

emissions from sources during SSM events at issue in this action fail to meet this most basic SIP 

requirement and are also inconsistent with the enforcement requirements of the CAA. Similarly, 

the enforcement discretion provisions at issue in this action that have the effect of barring 

enforcement by EPA or citizens fail to meet this requirement for enforceable emission 

limitations by interfering with the enforcement structure of the CAA as established by Congress. 

The affirmative defense provisions at issue are similarly inconsistent with the requirement that 

SIPs provide for enforcement of the NAAQS and also contravene the statutory jurisdiction of 

courts to determine liability and to impose remedies for violations of SIP requirements. Each of 

these types of deficient SIP provisions is thus inconsistent with legal requirements of the CAA 

for SIP provisions. Contrary to the claims of many commenters, the EPA has authority and 

responsibility to assure that a state’s SIP provisions in fact comply with fundamental legal 

requirements of the CAA as part of the obligation to ensure that SIPs protect the NAAQS.74 

 

74 The EPA notes that many of the specific SIP elements required in section 110(a)(2) are not 

themselves stated in terms of attainment and maintenance of the NAAQS. Instead, these 

requirements are part of the SIP structure that Congress deemed necessary to support 

implementation, maintenance and enforcement of the NAAQS, as well as to meet other 

objectives such as protection of PSD increments and visibility. 
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The Train-Virginia line of cases affirms the plain language of the Act—that in addition to 

providing generally for attainment and maintenance of the NAAQS, all state SIPs must satisfy 

the specific elements outlined in section 110(a)(2). Even setting aside that Train predated 

substantive revisions to the CAA that strengthened section 110(a)(2)(A) in ways relevant here,75

the Train Court clearly stated that section 110(a)(2) imposes additional requirements for state 

submissions to be accepted, independent of the general obligation to meet the NAAQS. Many 

commenters on the February 2013 proposal selectively quoted or cited only portions of the 

following excerpt from Train, omitting or ignoring the portions emphasized here: 

The Agency is plainly charged by the Act with the responsibility for setting the 

national ambient air standards. Just as plainly, however, it is relegated by the Act 

to a secondary role in the process of determining and enforcing the specific, 

source-by-source emission limitations which are necessary if the national 

standards it has set are to be met. Under § 110(a)(2), the Agency is required to 

approve a state plan which provides for the timely attainment and subsequent 

maintenance of ambient air standards, and which also satisfies that section’s other 

general requirements. The Act gives the Agency no authority to question the 

wisdom of a State’s choices of emission limitations if they are part of a plan 

 

75 For example, to the extent the Train Court was construing section 110(a)(2)’s emission 

limitation provision, it is important to note that while that statutory section before the Train 

Court required approvable SIPs to include certain controls “necessary to insure compliance with 

[the] primary or secondary standards” (i.e., the NAAQS),see CAA of 1970, Pub. L. 91-604, § 

4(a), 84 Stat. 1676, 1680 (December 31, 1970), that section now more broadly speaks of controls 

“necessary or appropriate to meet the applicable requirements of this chapter” (i.e., the CAA). 

Section 110(a)(2)(A) (emphasis added). Among the other relevant textual changes are the 

qualification that emission limitations and other controls be “enforceable,” id.; a statutory 

definition of “emission limitation” that adds requirements not contemplated by Train, compare 

Section 302(k), with Train, 421 U.S. at 78; as well as a recharacterization of section 110(a)(2)’s 

emission limitation requirement from one bearing on whether “[t]he Administrator shall approve 

such plan,” see Pub. L. 91-604, § 4(a), 84 Stat. at 1680, to a requirement expressly directed at 

what “[e]ach plan shall” include. 
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which satisfies the standards of § 110(a)(2) . . . . Thus [i.e., provided the state plan 

satisfies the basic requirements of § 110(a)(2)], so long as the ultimate effect of a 

State’s choice of emission limitations is compliance with the national standards 

for ambient air, the State is at liberty to adopt whatever mix of emission 

limitations it deems best suited to its particular situation.76 

When read in its entirety, without omitting the portions italicized above, Train clearly 

does not stand for the proposition that SIPs must be judged exclusively on the basis of whether 

they will ensure attainment and maintenance of the NAAQS. To the contrary, the Court made 

clear that approvable SIP submissions must not only provide for attainment and maintenance of 

the NAAQS but must also satisfy section 110(a)(2)’s “other general requirements . . . .”77

Furthermore, while states have great latitude to select emission limitations, Train explained that 

those emission limitations must nevertheless be “part of a plan which satisfies the standards of § 

110(a)(2) . . . .”78 Finally, the EPA notes that many commenters quoting the final sentence 

excerpted above typically excluded the word “Thus,” which references the preceding sentence 

stating that SIPs must “satisfy [section 110(a)(2)]’s other general requirements.”79 By omitting 

the word “thus,” and the passages concerning the obligation of states to comply with section 

110(a)(2) and other obligations of the CAA, the commenters disregard the critical point that the 

 

76 421 U.S. at 79 (emphasis added) (footnotes omitted). 

77 See id. (emphasis added). 

78 See id. The EPA notes that section 110(a)(2) and other sections relevant to SIPs in fact contain 

numerous procedural and substantive requirements that air agencies must meet. Section 110(a) is 

not composed of a single sentence that directs states merely to attain the NAAQS; it is replete 

with legal requirements applicable to SIPs that help to assure that a SIP will successfully meet 

that objective. 

79 See id. 
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EPA has the statutory responsibility to assure that state SIPs meet the specific requirements of 

the CAA, not merely that they provide for attainment of the NAAQS regardless of whether they 

meet other mandatory legal requirements.80 In short, the Train Court did not hold that SIPs must 

merely provide for attainment of the NAAQS even under the 1970 Act, much less the text of the 

CAA applicable today. To the contrary, the U.S. Supreme Court indicated that approvable state 

plans were also required to meet other legal specifications of the CAA for SIPs such as those in 

section 110(a)(2) and that the EPA’s responsibility is to determine whether they do so. The 

EPA’s own obligations with respect to evaluating SIPs under sections 110(k)(3), 110(l) and 193 

continue to provide this authority and responsibility today. 

After Train, one of the cases most frequently cited by commenters for its discussion of 

cooperative federalism was the D.C. Circuit’s decision in EME Homer City Generation, L.P. v. 

EPA, a case since overturned by the U.S. Supreme Court.81 In that case arising under section 

110(a)(2), the D.C. Circuit vacated the EPA’s Cross-State Air Pollution Rule for two reasons, 

one being related to statutory interpretation of section 110(a)(2)(D)(i), the other being “a second, 

entirely independent problem” based on the EPA’s purported overstep of the federalism bar 

 

80 As a related point, the EPA notes that commenters claiming that the proposed SIP call was a 

violation of cooperative federalism likewise typically did not address the existence or 

significance of sections 110(k), 110(l) and 193. All of these provisions indicate that the EPA has 

statutory authority and responsibility to approve or disapprove SIP submissions, based upon 

whether they meet applicable requirements of the CAA. The EPA fully explained its views 

concerning its authority and responsibility under these provisions in the February 2013 proposal. 

See 78 FR 12459 at 12471, 12477–78, 12483–89; Background Memorandum at 2–3. 

81 696 F.3d 7, 29 (D.C. Cir. 2012) rev’d, 134 S. Ct. 1584 (2014). 
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identified in the Train-Virginia line of cases.82 After recounting a list of decisions that recognize 

the cooperative-federalism structure of the CAA, the D.C. Circuit concluded that even though 

states have the “primary responsibility” for implementing the NAAQS, in this case they had no 

responsibility to address interstate transport until the EPA first quantified the obligations of the 

states. The dissent described the majority’s application of the Train-Virginia cases as “a redesign 

of Congress’s vision of cooperative federalism in implementing the CAA . . . .”83 The 

commenters approvingly cited to the D.C. Circuit’s EME Homer City decision, evidently to 

illustrate the importance of states’ role under section 110. That states are given the first 

opportunity to develop a SIP that complies with section 110 is not in dispute. What is in dispute 

are the authority and the responsibility of the EPA to take action when states fail to comply with 

all of the requirements for SIP provisions under the CAA, whether that requirement is to address 

interstate transport or to meet other specific legal requirements of the Act applicable to SIP 

provisions. 

The U.S. Supreme Court reversed the EME Homer City decision in June 2014,84

rendering suspect the D.C. Circuit’s interpretation of the Train-Virginia line of cases, as well as 

rendering suspect the commenters’ even broader characterization of that interpretation as per se

authorizing the states to create provisions such as the SSM exemptions and affirmative defenses 

 

82 Id. at 28. 

83 Id. at 38 (Rogers, J., dissenting). 

84 See EPA v. EME Homer City Generation, L.P., 134 S. Ct. 1584 (2014). 
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at issue in this SIP call. The U.S. Supreme Court held that the touchstone for identifying the 

division of responsibility between the EPA and the states is the text of section 110(a)(2) itself.85

Although this SIP call involves different requirements of section 110(a)(2) than the one at issue 

in EME Homer City—there, the interstate transport obligations of 110(a)(2)(D)(i)(I)—the Court 

expressly held that “[n]othing in the Act differentiates the Good Neighbor Provision from the 

several other matters a State must address in its SIP.”86 After the U.S. Supreme Court’s ruling, 

the EPA’s role under section 110’s cooperative-federalism framework—as the agency charged 

with reasonably interpreting the fundamental requirements of section 110(a)(2), and applying 

those reasonably interpreted requirements to state SIPs—cannot reasonably be in doubt.87 

The touchstone of the cooperative-federalism concept outlined in the Train-Virginia line 

of cases is that, under the authority of section 110, the EPA may not legally or functionally 

 

85 Id. at 1600–01. 

86 Id. at 1601 (citing, inter alia, section 110(a)(2)). 

87 See id. at 1593 (citing Chevron, 467 U.S. 837 (1984)). See, e.g., Oklahoma v. EPA, 723 F.3d 

1201, 1208 (10th Cir. 2013) cert. denied, 134 S. Ct. 2662 (2014) (applying Chevron to uphold 

EPA’s disapproval of a SIP for noncompliance with regional haze requirements in section 

110(a)(2)(J)); North Dakota v. EPA, 730 F.3d 750 (8th Cir. 2013) cert. denied, 134 S. Ct. 2662 

(2014) (applying Chevron to uphold EPA’s disapproval of a SIP for noncompliance with 

interstate visibility requirements in section 110(a)(2)(D)(i)(II)); Luminant Generation Co. LLC, 

v. EPA, 714 F.3d 841, 856 (5th Cir. 2013) cert. denied, 134 S. Ct. 387 (2013); Mont. Sulphur & 

Chem. Co. v. United States EPA, 666 F.3d 1174, 1180, 1189 (9th Cir. 2012), cert denied 133 S. 

Ct. 409 (2012) (“The Clean Air Act gives the EPA significant national oversight over air quality 

standards, to be exercised pursuant to statutory specifications, and provides EPA with regulatory 

discretion in key respects relevant to SIP calls and determinations about the attainment of the 

NAAQS”); Mich. Dep’t of Envtl. Quality v. Browner, 230 F.3d 181, 184–85 (6th Cir. 2000) 

(“Although states are given broad authority to design programs, the EPA has the final authority 

to determine whether a SIP meets the requirements of the CAA.”). 
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require a state to adopt a specific control measure in its SIP in response to a SIP call.88 On this 

point, the D.C. Circuit’s opinion in EME Homer City was largely in line with Train, Virginia, 

and other D.C. Circuit cases. In that decision, the court described the Train-Virginia federalism 

bar as prohibiting the EPA “from using the SIP process to adopt specific control measures.”89

The EME Homer court did not more broadly hold that section 110(a)(2) imposes no independent 

limits on state discretion by requiring them to meet legal requirements for SIP provisions, or that 

the EPA is prohibited from either interpreting 110(a)(2)’s basic requirements or reviewing state 

SIPs for compliance with those requirements. Accordingly, the EPA believes that to the extent 

that the D.C. Circuit’s EME Homer City decision is relevant to this action, the decision in fact 

supports the basic principle that the EPA has authority and responsibility to assure that states 

comply with legal requirements of the CAA applicable to SIP provisions. 

This view of what cooperative federalism prohibits is consistent with Train, where the 

U.S. Supreme Court stated that the EPA “is relegated by the [1970] Act to a secondary role in the 

process of determining and enforcing the specific, source-by-source emission limitations which 

are necessary if the national standards it has set are to be met.”90 It is also consistent with the 

Virginia decision, where the D.C. Circuit held that the EPA cannot under section 110 

functionally require states to “adopt[] particular control measures” in a SIP but must rather 

 

88 78 FR 12459 at 12489 & nn.89–90. 

89 See EME Homer City Generation, L.P., v. EPA, 696 F.3d at 29 (citing Michigan, 213 F.3d at 

687; Virginia, 108 F.3d at 1410) (emphasis added). 

90 421 U.S. at 79 (emphasis added). 
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ensure that states have a meaningful choice among alternatives.91 Moreover, it is consistent with 

the court’s view in Michigan v. EPA,

92 a case involving a SIP call, in which the D.C. Circuit 

interpreted and applied those precedents: 

Given the Train and Virginia precedent, the validity of the NOx budget program 

underlying the SIP call depends in part on whether the program in effect 

constitutes an EPA-imposed control measure or emission limitation triggering the 

Train-Virginia federalism bar: in other words, on whether the program constitutes 

an impermissible source-specific means rather than a permissible end goal.

However, the program’s validity also depends on whether EPA’s budgets allow 

the covered states real choice with regard to the control measure options 

available to them to meet the budget requirements.93 

Clearly, in this SIP call the EPA is leaving the states the freedom to correct the inappropriate 

provisions in any manner they wish as long as they comply with the constraints of section 

110(a)(2). 

Finally, this view is consistent with Appalachian Power Co. v. EPA, where the D.C. 

Circuit reiterated that Virginia “disapproved the EPA’s plan to reject SIPs that did not 

incorporate particular limits upon emissions from new cars.”94 The specific controls discussed in 

 

91 Commonwealth of Virginia v. EPA, 108 F.3d 1397, 1415 (D.C. Cir. 1997) (holding that 

functionally, in that case, “EPA’s alternative is no alternative at all”); see also Appalachian 

Power Co. v. EPA, 249 F.3d 1032, 1047 (D.C. Cir. 2001) (citing Virginia, 108 F.3d at 1406, 

1410) (“We did not suggest [in Virginia] that under § 110 states may develop their plans free of 

extrinsic legal constraints. Indeed, SIP development . . . commonly involves decisionmaking 

subject to various legal constraints.”). 

92 213 F.3d 663 (D.C. Cir. 2000). 

93 Id. at 687 (emphasis added). 

94 249 F.3d 1032, 1047 (D.C. Cir. 2001) (citing Virginia, 108 F.3d at 1410) (emphasis added). 
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these cases are quite different as both a legal and functional matter from the statutory constraints 

on the states’ exercise of discretion that the EPA is interpreting and applying in this action.95 

As explained in the February 2013 proposal, in this action the EPA is not requiring states 

to adopt any particular emission limitation or to impose a specific control measure in a SIP 

provision; the EPA is merely directly the states to address the fundamental requirements that all 

SIP provisions must meet.96 This SIP call outlines the principles and framework for how states 

can revise the existing deficient SIP provisions to meet a permissible end goal97—compliance 

with the Act. In so doing, the EPA is merely acting pursuant to its supervisory role under the 

CAA’s cooperative-federalism framework, to ensure that SIPs satisfy those broad requirements 

that section 110(a)(2) mandates state SIPs “shall” satisfy. With respect to section 110(a)(2)(A), 

this means that a SIP must at least contain legitimate, enforceable emission limitations to the 

extent they are necessary or appropriate “to meet the applicable requirements” of the Act. SIPs 

cannot contain unbounded director’s discretion provisions that functionally subvert the 

requirements of the CAA for approval and revision of SIP provisions. Likewise, SIPs cannot 

have enforcement discretion provisions or affirmative defense provisions that contravene the 

fundamental requirements concerning the enforcement of SIP provisions. Accordingly, the EPA 

believes that this SIP call fully accords with the federal-state partnership outlined in section 110, 

 

95 See id. 96 78 FR 12459 at 12489. 

97 See, e.g., Michigan, 213 F.3d at 687. 
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by providing the states meaningful latitude when developing a SIP submission, while 

“‘nonetheless subject[ing] the States to strict minimum compliances requirements’ and giv[ing] 

EPA the authority to determine a state’s compliance with those requirements.”98 

The EPA emphasizes that this action also allows states “real choice” concerning their SIP 

provisions, so long as the provisions are consistent with applicable requirements. For example, 

this SIP call does not establish any specific, source-by-source limitations. To the contrary, as 

described in section VII.A of this document, emission limitations meeting the requirements of 

section 110(a)(2)(A) may take a variety of forms. States are free under section 110(a)(2)(A) to 

include in their SIPs whatever emission limitations they wish, provided they comply with 

applicable legal requirements. Among those requirements are that an emission limitation in a SIP 

must be an “emission limitation” as defined in section 302(k) and that all controls—emission 

limitations and otherwise—must be sufficiently “enforceable” to ensure compliance with 

applicable CAA requirements. The SSM provisions at issue in this SIP call subvert both of these 

legal requirements. 

3. Comments that the EPA should expand the rulemaking to include additional SIP 

provisions that the commenters consider deficient with respect to SSM issues. 

Comment: Some commenters requested that the EPA expand its February 2013 proposed 

rulemaking to include additional SIP provisions that the commenters consider deficient with 

 

98 Michigan v. EPA, 213 F.3d 663, 687 (D.C. Cir. 2000) (quoting Union Elec. Co. v. EPA, 427 

U.S. 246, 256–57 (1976)); see Mont. Sulphur & Chem. Co. v. United States EPA, 666 F.3d 1174, 

1181 (9th Cir. 2012), cert. denied 133 S. Ct. 409 (2012) (“The Clean Air Act gives the EPA 

significant national oversight power over air quality standards, to be exercised pursuant to 

statutory specifications, and provides the EPA with regulatory discretion in key respects relevant 

to SIP calls and determinations about the attainment of NAAQS.”). 
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respect to SSM issues. Specifically, commenters identified SIP provisions in Wisconsin and New 

Hampshire. 

One commenter argued that “[i]t would substantially ease the administrative burden on 

EPA as well on public commenters” and “ensure that companies in all states are treated equally” 

if the EPA were to include “all SIPs with faulty SSM provisions in [a] consolidated SIP call.” 

Another commenter noted that “the interests of regulatory efficiency will be served” by adding 

additional SIP provisions to the SIP call because “all changes required by the policy underlying 

this rulemaking” to state SIPs would then be made at once. 

Response: The EPA acknowledges the requests made by the commenters concerning 

additional SIP provisions that may be inconsistent with CAA requirements. The EPA also agrees 

with the points made by the commenters concerning the potential benefits of expanding the 

rulemaking to include evaluation of additional provisions. However, in the February 2013 

proposal the EPA elected to review the specific SIP provisions identified by the Petitioner in the 

SIPs of 39 states to determine whether they are consistent with the CAA as interpreted in the 

EPA’s SSM Policy as requested in the Petition.99 Although there may be additional SIP 

provisions that are deficient, the EPA determined that it would first focus its review on those 

identified in the Petition in order to use EPA and state resources most efficiently. 

With respect to the specific additional SIP provisions identified by the commenters on the 

February 2013 proposal, the EPA also notes that it cannot take final action on any additional 

SSM-related SIP provisions without first providing an opportunity for public notice and 

comment with respect to those additional SIP provisions. The EPA agrees that an important 

 

99 February 2013 proposal, 78 FR 12459 (February 22, 2013). 
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objective of its action on the Petition is to provide complete, comprehensive and up-to-date 

guidance to all air agencies concerning SIP provisions that apply to emissions during SSM 

events. The EPA is endeavoring to do this by responding to the Petition fully and by updating its 

interpretation of the CAA in the SSM Policy to reflect the relevant statutory requirements and 

recent court decisions. All states should feel free to apply this revised guidance in reviewing their 

own SIP provisions and revising them as appropriate. The EPA may address other SSM-related 

provisions that may be inconsistent with EPA’s SSM Policy and the CAA in a later separate 

notice-and-comment action(s). The EPA has authority to address those provisions separately.100 

The EPA notes that with respect to the issue of affirmative defenses in SIP provisions, the 

Agency determined that it was necessary to amend its February 2013 proposal to take into 

consideration a recent court decision concerning the legal basis for such provisions. Thus, the 

EPA issued the SNPR to address this development in the law. Because of recent EPA actions and 

court decisions on this subject, the Agency determined that it was important to address not only 

the affirmative defense provisions identified in the Petition but also affirmative defense 

provisions that the EPA independently identified in six states’ SIPs. The SNPR was explicitly 

limited to the narrow concern of affirmative defense provisions. The EPA included these six 

states’ affirmative defense provisions in order to provide comprehensive guidance to all states 

concerning affirmative defense provisions in SIPs and to avoid confusion that may arise due to 

recent rulemakings and court decisions relevant to such provisions under the CAA. 

 

100 The EPA notes that it has received a separate petition for rulemaking requesting it to evaluate 

SIP provisions in the State of Wisconsin. The EPA is not taking action on that separate petition 

as part of this action but will take action on that petition in a future rulemaking. 
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The SIP call promulgated by the EPA in this action applies only to the particular SIP 

provisions identified in this notice, and the scope of the SIP call for each state is limited to those 

provisions. However, if states of their own accord wish to revise SIP provisions, beyond those 

identified in this SIP call, that they believe are inconsistent with the SSM Policy and the CAA, 

the EPA will review and act on those SIP revisions in accordance with CAA sections 110(k), 

110(l) and 193. 

4. Comments that the EPA should create regulatory text in 40 CFR part 51 to forbid SSM 

exemptions in SIP provisions if the CAA precludes them. 

Comment: Commenters argued that the EPA, before issuing a SIP call requiring states to 

revise SIP provisions containing exemptions for emissions during SSM events, should first have 

promulgated specific regulations articulating that such exemptions are precluded by the CAA. 

According to commenters, taking this approach would have given states more certainty and 

clarity and provided states with more time to develop SIP revisions consistent with those 

regulatory requirements. Commenters also asserted that it is not appropriate for the EPA to 

proceed with a SIP call to states without prior rulemaking to create regulatory provisions 

explicitly prohibiting SSM exemptions in SIPs, given that the Agency has previously approved 

the SIP provisions at issue. 

Response: The EPA disagrees with the commenters’ argument that the Agency must first 

promulgate regulations to make clear that exemptions for emissions during SSM events are not 

permissible in SIPs, prior to issuing this SIP call. The EPA likewise disagrees with the 

implication that its authority to promulgate a SIP call is restricted only to those issues for which 

there is specifically applicable regulatory text, as opposed to requirements related to statutory 

provisions, court decisions or other legal or factual bases for a determination that an existing SIP 
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provision is substantially inadequate to meet CAA requirements. The EPA disagrees with the 

commenters for several reasons. 

First, the CAA does not impose a general obligation upon the Agency to promulgate 

regulations applicable to all SIP requirements. Although the EPA has elected to promulgate 

regulations to address a broad variety of issues relevant to SIPs, 101 the Agency is not obligated to 

promulgate regulations unless there is a specific statutory mandate that it do so.102 In addition, 

the EPA has authority under section 301 to promulgate such regulations as it deems necessary to 

implement the CAA (e.g., to fill statutory gaps left by Congress for the EPA to fill or to clarify 

ambiguous statutory language). With respect to SIP requirements, however, the EPA has elected 

to promulgate regulations or to issue guidance to states to address different requirements, as 

appropriate.103 In short, there is no specific statutory requirement for the EPA to promulgate 

regulations with respect to the types of deficiencies in SIP provisions at issue in this action, prior 

to issuing a SIP call. 

Second, the EPA has historically elected to address the key issues relevant to this SIP call 

action in guidance. Through a series of guidance documents, issued in 1982, 1983, 1999 and 

 

101 See, generally, 40 CFR part 51 (including regulations applicable to many aspects of SIPs. 

102 See, e.g., CAA section 169A(a)(4) (requiring the EPA to promulgate regulations governing 

the requirements relevant to SIP requirements for purposes of regional haze reduction). 

103 See, e.g., “State Implementation Plans; General Preamble for the Implementation of Title I of 

the Clear Air Act Amendments of 1990,” 57 FR 13498 (April 16, 1992) (the “General Preamble” 

that continues to provide guidance recommendations to states for certain attainment plan 

requirements for various NAAQS); 40 CFR part 51, subpart Z (imposing regulatory 

requirements for certain attainment plan requirements for the 1997 PM2.5 NAAQS). 
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2001, the EPA has previously explained its interpretations of the CAA with respect to SIP 

provisions that contain automatic SSM exemptions, discretionary SSM exemptions, the exercise 

of enforcement discretion for SSM events and affirmative defenses for SSM events. Starting in 

the 1982 SSM Guidance, the EPA explicitly acknowledged that it had previously approved some 

SIP provisions related to emissions during SSM events that it should not have, because the 

provisions were inconsistent with requirements for SIPs. In addition, the EPA has in rulemakings 

applied its interpretation of the CAA with respect to issues such as exemptions for emissions 

during SSM events and these actions have been approved by courts.104 Under these 

circumstances, the EPA does not agree that promulgation of generally applicable regulations was 

necessary to put states on notice of the Agency’s interpretation of the CAA with respect to these 

issues, prior to issuance of a SIP call. 

Finally, the EPA’s authority under section 110(k)(5) is not limited, expressly or 

otherwise, solely to inadequacies related to regulatory requirements. To the contrary, section 

110(k)(5) refers broadly to attainment and maintenance of the NAAQS, adequate mitigation of 

interstate transport and compliance with “any requirement of” the CAA. In addition, section 

110(k)(5) specifically contemplates situations such as this one, “whenever” the EPA finds 

previously approved SIP provisions to be deficient. Nothing in the CAA requires the EPA to 

conduct a separate rulemaking clarifying its interpretation of the CAA prior to issuance of this 

SIP call. For the types of deficiencies at issue in this action, the EPA believes that the statutory 

 

104 See, e.g., Michigan v. EPA, 213 F.3d 663 (D.C. Cir. 2000) (upholding the “NOx SIP Call” to 

states requiring revisions to previously approved SIPs with respect to ozone transport and section 

110(a)(2)(D)(i)(I)); “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah 

State Implementation Plan Revision,” 74 FR 21639 (April 18, 2011) (the EPA issued a SIP call 

to rectify SIP provisions dating back to 1980). 
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requirements of the CAA itself and recent court decisions concerning those statutory provisions 

provide sufficient basis for this SIP call. 

For the foregoing reasons, the EPA disagrees that before requiring states to revise SIPs 

that contain provisions with SSM exemptions, the EPA first must promulgate regulations 

explicitly stating that such exemptions are impermissible under the CAA. In addition, the EPA 

notes that although it is not promulgating generally applicable regulations in this action, it is 

nonetheless revising its guidance in the SSM Policy through rulemaking and thereby providing 

states and other parties the opportunity to comment on the Agency’s interpretation of the CAA 

with respect to this issue. 

5. Comments that the EPA did not provide a sufficiently long comment period on the 

proposal in general or as contemplated in Executive Order 13563. 

Comment: A number of commenters argued that the comment period provided by the 

EPA for the February 2013 proposal was “at odds with Executive Order 13,563.” The 

commenters alleged that the comment period was “unconscionably short,” even so short as to be 

“arbitrary and capricious” because, in order to provide comments, “impacted States and 

industries must perform the data collection and analysis necessary to evaluate the need for the 

proposed rule and its impacts.” Further, the commenters alleged, the “EPA’s failure and refusal 

to perform any technical analyses of the feasibility of source operations after the elimination of 

SSM provisions or the likely capital and operating costs of additional control equipment required 

to meet numeric standards during all operational periods has denied the States, the affected 

parties, and the public a meaningful opportunity to evaluate and comment upon the proposed 

rule.” Finally, one commenter asserted that Executive Order 13563 requires that “[b]efore 

issuing a notice of proposed rulemaking, each agency, where feasible and appropriate, shall seek 
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the views of those who are likely to be affected.”105 The commenter claimed that because the 

EPA allegedly “failed to seek the views of those who are likely to be affected and those who are 

potentially subject to such rulemaking, EPA’s actions ignore the requirements of the Executive 

Order.” 

Response: The EPA disagrees that it has not provided sufficiently long comment periods 

to address the specific issues relevant to this action. The EPA has followed all steps of a noticeand-comment rulemaking, as governed by statutes, regulations and executive orders, including a 

robust process for public participation. When the EPA proposed to take action on the Petition, it 

solicited public comment on all aspects of its proposed response to the issues in the Petition and 

in particular on its proposed action with respect to each of the specific existing SIP provisions 

identified in the Petition as inconsistent with the requirements of the CAA. In response to 

requests, the EPA extended the public comment period for this proposal to May 13, 2013, which 

is 80 days from the date the proposed rulemaking was published in the Federal Register and 89 

days from the date the proposed rulemaking was posted on the EPA’s website.106 The EPA also 

held a public hearing concerning the proposed rule on March 12, 2013. 

Executive Order 13563 provides that each agency should “afford the public a meaningful 

opportunity to comment through the Internet on any proposed regulation, with a comment period 

that should generally be at least 60 days.”107 The length of the Agency’s comment period for the 

original proposed rulemaking well-exceeded this standard. The EPA also facilitated comment on 

 

105 See E.O. 13563 section 2(c). 

106 See “State Implementation Plans: Response to Petition for Rulemaking; Findings of 

Substantial Inadequacy; and SIP Calls To Amend Provisions Applying to Excess Emissions 

During Periods of Startup, Shutdown, and Malfunction; Extension of Comment Period,” 78 FR 

20855 (April 8, 2013), in the rulemaking docket at EPA-HQ-OAR-2012-0322-0126. 

107 See E.O. 13563 section 2(b) (emphasis added). 
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the action by providing a full and detailed evaluation of the relevant issues in the February 2013 

proposal, the background memorandum supporting the proposal and the SNPR. 

When considering whether an agency has provided for adequate public input, reviewing 

courts are generally most concerned with the overall adequacy of the opportunity to comment. 

This, in turn, typically depends on steps the agency took to notify the public of information that 

is important to this action. Comment period length is only one factor that courts consider in this 

analysis, and courts have regularly found that comment periods of significantly shorter length 

than the 80 days provided here on the February 2013 proposal were reasonable in various 

circumstances.108 Given the nature of the issues raised by the Petition, the EPA believes that the 

comment period was appropriate and sufficient to allow for full analysis of the issues and 

preparation of comments. The number of comments received on the February 2013 proposal, and 

the breadth of issues and level of detail provided by the commenters, both supportive and 

adverse, serve to support the EPA’s view on this point. 

The EPA also disagrees with respect to the claims of commenters that the comment 

period was insufficient because the EPA should provide time for commenters to evaluate and 

analyze fully the possible ultimate impacts of the SIP call upon particular sources, to determine 

what type of SIP revision by a state is appropriate in response to a SIP call, or to ascertain what 

specific new emission limitation or control measure requirement states should impose upon 

 

108 See, e.g., Omnipoint Corp. v. Fed. Commc’ns Comm’n, 78 F.3d 620, 629 (D.C. Cir. 1996) 

(approving a 7-day comment period); Florida Power & Light Co. v. United States, 846 F.2d 765, 

772 (D.C. Cir. 1988) (holding a 15-day comment period to not be unreasonable under the 

governing circumstances); Conn. Light & Power Co. v. NRC, 673 F.2d 525, 534 (D.C. Cir. 1982) 

(holding 30 days not unreasonable in the particular situation); Am. Farm Bureau Fedn v. United 

States EPA, 984 F.Supp.2d 289, 333 (M.D. Pa. 2013) (holding that a 45-day comment period 

was adequate despite “technical complexities of the regulations and issues raised”). 
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sources in such a future SIP revision. The EPA’s action on the Petition concerning specific 

existing SIP provisions is focused upon whether those existing provisions meet fundamental 

legal requirements of the CAA for SIP provisions. The EPA is not required to provide a 

comment period for this action that allows states actually to determine which of the potential 

forms of SIP revision they may wish to undertake, or to complete those SIP revisions, as part of 

this rulemaking. The state and EPA rulemaking processes on the SIP revisions in response to this 

SIP call will provide time for further evaluation of the issues raised by commenters. 

As explained in the February 2013 proposal, the EPA does not interpret section 110(k)(5) 

to require it to “prove causation” concerning what precise impacts illegal SIP provisions are 

having on CAA requirements, such as attainment and maintenance of the NAAQS and 

enforcement of SIP requirements.109 Nor is the EPA directing states to adopt a specific control 

measure in response to the SIP call; the decision as to how to revise the affected SIP provisions 

in response to the SIP call is left to the states. The state’s response to the SIP call will be 

developed in future rulemaking actions at both the state and federal level which will similarly be 

subject to full notice-and-comment proceedings. In electing to proceed by SIP call under section 

110(k)(5), rather than by error correction under section 110(k)(6), the EPA is providing affected 

states with the maximum time permitted by statute to determine how best to revise their SIP 

provisions, consistent with CAA requirements. During this process, the commenters and other 

stakeholders will have the opportunity to participate in the development of the SIP revision, 

including decisions such as how the state elects to revise the deficient SIP provisions (e.g., 

 

109 This issue is addressed in more detail in section VIII.A.1 of this notice. 
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merely to eliminate an exemption for SSM events or to impose an alternative emission limitation 

applicable to startup and shutdown). 

The questions posed by the commenters about what specific emission limitations should 

apply during startup and shutdown events, what control measures will meet applicable CAA 

legal requirements, what control measures will be effective and cost-effective to meet applicable 

legal standards and other similar questions are exactly the sorts of issues that states will evaluate 

in the process of revising affected SIP provisions. Moreover, these are the same sorts of 

questions that the EPA will be evaluating when it reviews state SIP submissions made in 

response to the SIP call. The EPA is not required, by Executive Order 13563 or otherwise, to 

provide a comment period that would allow for all future actions in response to the SIP call to 

occur before issuing the SIP call. The EPA anticipates that the commenters will be able to 

participate actively in the actions that will happen in due course in response to this SIP call. 

6. Comments that this action is not “nationally applicable” for purposes of judicial review. 

Comment: Commenters alleged that the SSM SIP call is not “nationally applicable” for 

purposes of judicial review. One state commenter cited ATK Launch Systems, for the proposition 

that the specific language of the regulation being challenged indicates whether an action is 

nationally or locally/regionally applicable. Because a SIP provision subject to this SIP call is 

state-specific, the commenter argued, it is of concern only for that state and thus the SIP call is a 

locally applicable action.110 

Response: The EPA disagrees with the commenter that the SIP call is not a nationally 

applicable action. In this rulemaking, the EPA is responding to a Petition that requires the 

 

110 See 651 F.3d 1194 (10th Cir. 2011). 
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Agency to reevaluate its interpretations of the CAA in the SSM Policy that apply to SIP 

provisions for all states across the nation. In so doing, the EPA is reiterating its interpretations 

with respect to some issues (e.g., that SIP provisions cannot include exemptions for emissions 

during SSM events) and revising its interpretations with respect to others (e.g., so that SIP 

provisions cannot include affirmative defenses for emissions during SSM events). In addition to 

reiterating and updating its interpretations with respect to SIP provisions in general, the EPA is 

also applying it interpretations to specific existing provisions in the SIPs of 41 states. Through 

this action the EPA is establishing a national policy that it is applying to states across the nation. 

As with many nationally applicable rulemakings, it is true that this action also has local or 

regional effects in the sense that EPA is requiring 37 individual states to submit revisions to their 

SIPs. However, through this rulemaking the EPA is applying the same legal and policy 

interpretation to each of these states. Thus, the underlying basis for the SIP call has “nationwide 

scope and effect” within the meaning of section 307(b)(1) as explained by the EPA in the 

February 2013 proposal. A key purpose of the CAA in channeling to the D.C. Circuit challenges 

to EPA rulemakings that have nationwide scope and effect is to minimize instances where the 

same legal and policy basis for decisions may be challenged in multiple courts of appeals, which 

instances would potentially lead to inconsistent judicial holdings and a patchwork application of 

the CAA across the country. We note that in the ATK Launch case cited by commenters, the U.S. 

Court of Appeals for the Tenth Circuit (Tenth Circuit) in fact transferred to the D.C. Circuit 

challenges to the designation of two areas in Utah that were part of a national rulemaking 

designating areas across the U.S. for the PM2.5 NAAQS. In transferring the challenges to the 

D.C. Circuit, the Tenth Circuit noted that the designations rulemaking “reached areas coast to 
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coast and beyond” and that the EPA had applied a uniform process and standard.111 Significantly, 

in support of its decision to transfer the challenges to the D.C. Circuit, the Tenth Circuit stated: 

“The challenge here is more akin to challenges to so-called ‘SIP Calls,’ which the Fourth and 

Fifth Circuits have transferred to the D.C. Circuit ... Although each of the SIP Call petitions 

challenged the revision requirement as to a particular state, the SIP Call on its face applied the 

same standard to every state and mandated revisions based on that standard to states with nonconforming SIPs in multiple regions of the country.”112 

7. Comments that the EPA was obligated to address and justify the potential costs of the 

action and failed to do so correctly. 

Comment: Several commenters alleged that the EPA has failed to address the costs 

associated with this rulemaking action appropriately and consistent with legal requirements. In 

particular, commenters alleged that the EPA is required to address costs of various impacts of 

this SIP call, including the costs that may be involved in changes to emissions controls or 

operation at sources and the costs to states to revise permits and revise SIPs in response to the 

SIP call. 

Commenters also alleged that the EPA has failed to comply with Executive Order 12291, 

Executive Order 12866, Executive Order 13211, the Regulatory Flexibility Act and the 

Unfunded Mandates Reform Act. 

One commenter supported the EPA’s approach with respect to cost. 

Response: The EPA disagrees with commenters concerning its compliance with the 

Executive Orders and statutes applicable to agency rulemaking in general. The commenters are 

 

111 Id., 651 F.3d at 1197. 

112 Id., 651 F.3d at 1199. 
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simply in error that the EPA did not properly consider the costs imposed by this SIP call action, 

as required by law. As explained in the February 2013 proposal, to the extent that the EPA is 

issuing a SIP call to a state under section 110(k)(5), the Agency is only requiring a state to revise 

its SIP to comply with existing requirements of the CAA. The EPA’s action, therefore, would 

leave to states the choice of how to revise the SIP provision in question to make it consistent 

with CAA requirements and of determining, among other things, which of several lawful 

approaches to the treatment of excess emissions during SSM events will be applied to particular 

sources. Therefore, the EPA considers the only direct costs of this rulemaking action to be those 

to states associated with preparation and submission of a SIP revision by those states for which 

the EPA issues a SIP call. Examples of such costs could include development of a state rule, 

conducting notice and public hearing and other costs incurred in connection with a SIP 

submission. 

The commenters also incorrectly claim that the EPA failed to comply with Executive 

Order 12291. That Executive Order was explicitly revoked by Executive Order 12866, which 

was signed by President Clinton on September 30, 1993. 

The commenters are likewise incorrect that the EPA did not comply with Executive 

Order 12866. This action was not deemed “significant” due to the cost it will impose as the 

commenters claimed. This action is a “significant regulatory action” as that term is defined in 

Executive Order 12866, because it raises novel legal or policy issues. Accordingly, the EPA 

submitted the February 2013 proposal, the SNPR and the final action to the Office of 

Management and Budget (OMB) for review. Changes made in response to OMB review are 

documented in the docket for this action. The EPA believes it has fully complied with Executive 

Order 12866. 
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As stated in the February 2013 proposal, the EPA does not believe this is a “significant 

energy action” as defined in Executive Order 13211, because it is not likely to have a significant 

adverse effect on the supply, distribution or use of energy. As described earlier, this action 

merely requires that states revise their SIPs to comply with existing requirements of the CAA. 

States have the choice of how to revise the deficient SIP provisions that are the subject of this 

action; there are a variety of different ways that states may treat the issue of excess emissions 

during SSM events consistent with CAA requirements for SIPs. This action merely prescribes 

the EPA’s action for states regarding their obligations for SIPs under the CAA, and therefore it is 

not a “significant energy action” under Executive Order 13211. 

With respect to the Regulatory Flexibility Act (RFA), as the EPA explained in the 

February 2013 proposal, courts have interpreted the RFA to require a regulatory flexibility 

analysis only when small entities will be subject to the requirements of the rule.113 This action 

will not impose any requirements on small entities. Instead, it merely reiterates the EPA’s 

interpretation of the statutory requirements of the CAA. To the extent that the EPA is issuing a 

SIP call to a state under section 110(k)(5), the EPA is only requiring the state to revise its SIP to 

comply with existing requirements of the CAA. In turn, the state will determine whether and 

how to regulate specific sources, including any small entities, through the process of deciding 

how to revise a deficient SIP provision. The EPA’s action itself will not have a significant 

economic impact on a substantial number of small entities. 

As the EPA explained in the February 2013 proposal, this action is not subject to the 

requirements of the Unfunded Mandates Reform Act (UMRA) because it does not contain a 

 

113 See, e.g., Michigan v. EPA, 213 F.3d 663 (D.C. Cir. 2000); Mid-Tex Elec. Co-op, Inc. v. 

FERC, 773 F.2d 327 (D.C. Cir. 1985). 
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federal mandate that may result in expenditures of $100 million or more for state, local and tribal 

governments, in the aggregate, or the private sector in any one year. With respect to the impacts 

on sources, the EPA’s action in this rulemaking is not directly imposing costs on any sources. 

The EPA’s action is merely directing states to revise their SIPs in order to bring them into 

compliance with the legal requirements of the CAA for SIP provisions. In response to the SIP 

call, the states will determine how best to revise their deficient SIP provisions in order to meet 

CAA requirements. It is thus the states that will make the decisions concerning how best to 

revise their SIP provisions and will determine what impacts will ultimately apply to sources as a 

result of those revisions. 

8. Comments that the EPA’s action violates procedural requirements of the CAA or the 

APA, because the EPA is acting on the Petition, updating its SSM Policy and applying its 

interpretation of the CAA to specific SIP provisions in one action. 

Comment: Commenters argued that the EPA’s proposed action on the Petition, which 

includes simultaneous updating of its interpretations of the CAA in the SSM Policy and 

application of those revised interpretations to existing SIP provisions, is in violation of 

procedural requirements of the CAA and the APA. According to the commenters, the EPA’s 

combination of actions is a “subterfuge” to avoid notice and comment on the proposed actions in 

the February 2013 proposal. The commenters claimed that the EPA could only take these actions 

through two or more separate rulemaking actions. By proposing to update its interpretation of the 

CAA in the SSM Policy through notice-and-comment rulemaking and proposing to apply its 

interpretation of the CAA through notice-and-comment rulemaking to existing SIP provisions, 

the commenters claimed, the EPA has prejudged the outcome of this action. 
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Response: The EPA does not agree that is required to take this action in multiple separate 

rulemakings as claimed by the commenters. First, the EPA notes that the commenters allege that 

the Agency is failing to proceed by notice and comment in a comment letter submitted on the 

February 2013 proposal. The fact that the commenters level this allegation in comments on the 

proposal belies their overarching procedural argument that the EPA is failing to subject its 

interpretations of the CAA to notice-and-comment rulemaking. Second, although the EPA could 

elect to undertake two or more separate notice-and-comment rulemakings in order to answer the 

Petition, to revise its interpretations of the CAA in the SSM Policy and to evaluate existing 

provisions in state SIPs against the requirements of the CAA, there is no requirement for the 

Agency to do so. To the contrary, the EPA believes that it is preferable to take these interrelated 

actions in a combined rulemaking process. This combined approach allows the EPA to explain 

its actions comprehensively and in their larger context. The combined approach allows 

commenters to participate more meaningfully by considering together the proposed action on the 

Petition, the proposed interpretations of the CAA in the SSM Policy and the proposed 

application of the EPA’s interpretation to specific SIP provisions. By addressing the interrelated 

actions together and comprehensively, the EPA is striving to be efficient with the resources of 

both regulators and regulated parties. Most importantly, by combining these actions the EPA is 

being responsive to the need for prompt evaluation of the SIP provisions at issue and for 

correction of those found to be legally deficient in a timely fashion. Far from “prejudging” the 

issues, the EPA explicitly sought comment on all aspects of the February 2013 proposal and 

sought additional comment on issues related to affirmative defense provisions in the SNPR. 

Naturally, the EPA’s proposal and supplemental proposal reflected its best judgments on the 
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proper interpretations of the CAA and application of those interpretations to the issues raised by 

the Petition, as of the time of the February 2013 proposal and the SNPR. 

VI. Final Action in Response to Request that the EPA Limit SIP Approval to the Text of 

State Regulations and Not Rely upon Additional Interpretive Letters from the State 

A. What the Petitioner Requested 

The Petitioner’s third request was that when the EPA evaluates SIP revisions submitted 

by a state, the EPA should require “all terms, conditions, limitations and interpretations of the 

various SSM provisions to be reflected in the unambiguous language of the SIPs themselves.”114

The Petitioner expressed concern that the EPA has previously approved SIP submissions with 

provisions that “by their plain terms” do not appear to comply with the EPA’s interpretation of 

CAA requirements embodied in the SSM Policy and has approved those SIP submissions in 

reliance on separate “letters of interpretation” from the state that construe the provisions of the 

SIP submission itself to be consistent with the SSM Policy.115 Because of this reliance on 

interpretive letters, the Petitioner argued that “such constructions are not necessarily apparent 

from the text of the provisions and their enforceability may be difficult and unnecessarily 

complex and inefficient.”116 The Petitioner cited various past rulemaking actions to illustrate 

how EPA approval of ambiguous SIP provisions can inject unintended confusion for regulated 

 

114 Petition at 16. 

115 Petition at 14. 

116 Petition at 15. 
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entities, regulators, and the public in the future, especially in the context of future enforcement 

actions. Accordingly, the Petitioner requested that the EPA discontinue reliance upon 

interpretive letters when approving state SIP submissions, regardless of the circumstances. A 

more detailed explanation of the Petitioner’s arguments appears in the 2013 February 

proposal.117 

B. What the EPA Proposed 

In the February 2013 proposal, the EPA proposed to deny the Petition with respect to this 

issue. The EPA explained the basis for this proposed disapproval in detail, including a discussion 

of the statutory provisions that the Agency interprets to permit this approach, an explanation of 

why this approach makes sense from both a practical and an efficiency perspective under some 

circumstances, and a careful explanation of the process by which EPA intends to rely on 

interpretive letters in order to assure that the concerns of the Petitioner with respect to potential 

future disputes about the meaning of SIP provisions should be alleviated. 

C. What Is Being Finalized In This Action 

The EPA is taking final action to deny the Petition on this request. The EPA believes that 

it has statutory authority to rely on interpretive letters to resolve ambiguity in a SIP submission 

under appropriate circumstances and so long as the state and the EPA follow an appropriate 

process to assure that the rulemaking record properly reflects this reliance. To avoid any 

misunderstanding about the reasons for this denial or any misunderstandings about the 

circumstances under which, or the proper process by which, the EPA intends to rely interpretive 

letters, the Agency is repeating its views in this final action in detail. 

 

117 See February 2013 proposal, 78 FR 12459 at 12474 (February 22, 2013). 
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As stated in the February 2013 proposal, the EPA agrees with the core principle 

advocated by the Petitioner, i.e., that the language of regulations in SIPs that pertain to SSM 

events should be clear and unambiguous. This is necessary as a legal matter but also as a matter 

of fairness to all parties, including the regulated entities, the regulators, and the public. In some 

cases, the lack of clarity may be so significant that amending the state’s regulation may be 

warranted to eliminate the potential for confusion or misunderstanding about applicable legal 

requirements that could interfere with compliance or enforcement. Indeed, as noted by the 

Petitioner, the EPA has requested that states clarify ambiguous SIP provisions when the EPA has 

subsequently determined that to be necessary.118 

However, the EPA believes that the use of interpretive letters to clarify ambiguity or 

perceived ambiguity in the provisions in a SIP submission is a permissible, and sometimes 

necessary, approach under the CAA. Used correctly, and with adequate documentation in the 

Federal Register and the docket for the underlying rulemaking action, reliance on interpretive 

letters can serve a useful purpose and still meet the enforceability concerns of the Petitioner. So 

long as the interpretive letters and the EPA’s reliance on them is properly explained and 

documented, regulated entities, regulators, and the public can readily ascertain the existence of 

interpretive letters relied upon in the EPA’s approval that would be useful to resolve any 

perceived ambiguity. By virtue of being part of the stated basis for the EPA’s approval of that 

provision in a SIP submission, the interpretive letters necessarily establish the correct 

interpretation of any arguably ambiguous SIP provision. In other words, the rulemaking record 

should reflect the shared state and EPA understanding of the meaning of a provision at issue at 

 

118 See, e.g., “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah State 

Implementation Plan Revision,” 76 FR 21639 at 21648 (April 18, 2011). 
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the time of the approval, which can then be referenced should any question about the provision 

arise in a future enforcement action. 

In addition, reliance on interpretive letters to address concerns about perceived ambiguity 

can often be the most efficient and timely way to resolve concerns about the correct meaning of 

regulatory provisions. Both air agencies and the EPA are required to follow time- and resourceintensive administrative processes in order to develop and evaluate SIP submissions. It is 

reasonable for the EPA to exercise its discretion to use interpretive letters to clarify concerns 

about the meaning of regulatory provisions, rather than to require air agencies to reinitiate a 

complete administrative process merely to resolve perceived ambiguity in a provision in a SIP 

submission.119 In particular, the EPA considers this an appropriate approach where reliance on 

such an interpretive letter allows the air agency and the EPA to put into place SIP provisions that 

are necessary to meet important CAA objectives and for which unnecessary delay would be 

counterproductive. For example, where an air agency is adopting emission limitations for 

purposes of attaining the NAAQS in an area, a timely letter from the air agency clarifying that an 

enforcement discretion provision is applicable only to air agency enforcement personnel and has 

no bearing on enforcement by the EPA or the public could help to assure that the provision is 

approved into the SIP promptly and thus allow the area to reach attainment more expeditiously 

than requiring the air agency to undertake a time-consuming administrative process to make a 

minor clarifying change in the regulatory text. 

 

119 CAA section 110(k) directs the EPA to act on SIP submissions and to approve those that meet 

statutory and regulatory requirements. Implicit in this authority is the discretion, through 

appropriate notice-and-comment rulemaking, to determine whether or not a given SIP provision 

meets such requirements, in reliance on the information that the EPA considers relevant for this 

purpose. 
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There are multiple reasons why the EPA does not agree with the Petitioner with respect 

to the alleged inadequacy of using interpretive letters to clarify specific ambiguities in a SIP 

submission and the SIP provisions that may ultimately result from approval of such a 

submission, provided this process is done correctly. First, under section 107(a), the CAA gives 

air agencies both the authority and the primary responsibility to develop SIPs that meet 

applicable statutory and regulatory requirements. However, the CAA generally does not specify 

exactly how air agencies are to meet the requirements substantively, nor does the CAA specify 

that air agencies must use specific regulatory terminology, phraseology, or format, in provisions 

submitted in a SIP submission. Air agencies each have their own requirements and practices with 

respect to rulemaking, making flexibility respecting terminology on the EPA’s part appropriate, 

so long as CAA requirements are met. 

As a prime example relevant to the SSM issue, CAA section 110(a)(2)(A) requires that a 

state’s SIP shall include “enforceable emission limitations and other control measures, means, or 

techniques (including economic incentives such as fees, marketable permits, and auctions of 

emissions rights) as well as schedules and timetables for compliance as may be necessary or 

appropriate to meet the applicable requirements of” the CAA. Section 302(k) of the CAA further 

defines the term “emission limitation” in important respects but nevertheless leaves room for 

variations of approach: 

...a requirement established by the State or Administrator which limits the 

quantity, rate, or concentration of emissions of air pollutants on a continuous 

basis, including any requirement relating to the operation or maintenance of a 

source to assure continuous emission reduction, and any design, equipment, work 

practice or operational standard promulgated under [the CAA]. 

Even this most basic requirement of SIPs, the inclusion of enforceable “emission 

limitations,” allows air agencies discretion in how to structure or word the emission limitations, 
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so long as the provisions meet fundamental legal requirements of the CAA.120 Thus, by the 

explicit terms of the statute and by design, air agencies generally have considerable discretion in 

how they elect to structure or word their state regulations submitted to meet CAA requirements 

in a SIP. 

Second, under CAA section 110(k), the EPA has both the authority and the responsibility 

to assess whether a SIP submission meets applicable CAA and regulatory requirements. Given 

that air agencies have authority and discretion to structure or word SIP provisions as they think 

most appropriate, so long as the SIP provisions meet CAA and regulatory requirements, the 

EPA’s role is to evaluate whether those provisions in fact meet those legal requirements.121

Necessarily, this process entails the exercise of judgment concerning the specific text of 

regulations, with regard both to content and to clarity. Because actions on SIP submissions are 

subject to notice-and-comment rulemaking, there is also the opportunity for other parties to 

identify SIP provisions that they consider problematic and to bring to the EPA’s attention any 

concerns about ambiguity in the meaning of the SIP provisions under evaluation. 

Third, careful review of regulatory provisions in a SIP submission can reveal areas of 

potential ambiguity. It is essential, however, that regulations are sufficiently clear that regulated 

entities, regulators and the public can all understand the SIP requirements. Where the EPA 

 

120 The EPA notes that notwithstanding discretion in wording in regulatory provisions, many 

words have specific recognized legal meaning whether by statute, regulation, case law, 

dictionary definition, or common usage. For example, the term “continuous” has a specific 

meaning that must be complied with substantively, however the state may elect to word its 

regulatory provisions. 

121 See, e.g., Luminant Generation Co. v. EPA, 699 F.3d 427 (5th Cir. 2012) (upholding the 

EPA’s disapproval in part of affirmative defense provision with unclear regulatory text); US 

Magnesium, LLC v. EPA, 690 F.3d 1157, 1170 (10th Cir. 2012) (upholding the EPA’s issuance 

of a SIP call to clarify a provision that could be interpreted in a way inconsistent with CAA 

requirements). 
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perceives ambiguity in draft SIP submissions, it endeavors to resolve those ambiguities through 

interactions with the relevant air agency even in advance of the SIP submission. On occasion, 

however, there may still remain areas of regulatory ambiguity in a SIP submission’s provisions 

that the EPA identifies, either independently or as a result of public comments on a proposed 

action, for which resolution is both appropriate and necessary as part of the rulemaking action. 

In such circumstances, the ambiguity may be so significant as to require the air agency to 

revise the regulatory text in its SIP submission in order to resolve the concern. At other times, 

however, the EPA may determine that with adequate explanation from the state, the provision is 

sufficiently clear and complies with applicable CAA and associated regulatory requirements. In 

some instances, the air agency may supply the explanation necessary to resolve any potential 

ambiguity in a SIP submission by sending an official letter from the appropriate authority. When 

the EPA bases its approval of a SIP submission in reliance on the air agency’s official 

interpretation of the provision, that reading is explicitly incorporated into the EPA’s action and is 

memorialized as the proper intended reading of the provision. In other words, the state and the 

EPA will have a shared understanding of the proper interpretation of the provision, and that 

interpretation will provide the basis for the approval of that provision into the SIP. The 

interpretation will also be clearly identified and presented for the public and regulated entities in 

the Federal Register notice approving the SIP submission. 

For example, in the Knoxville redesignation action that the Petitioner noted in the 

Petition, the EPA took careful steps to ensure that the perceived ambiguity raised by commenters 

was substantively resolved and fully reflected in the rulemaking record, i.e., through inclusion of 

the interpretive letters in the rulemaking docket, quoting relevant passages from the letters in the 

Federal Register, and carefully evaluating the areas of potential ambiguity in response to public 
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comments on a provision-by-provision basis. By discussing the resolution of the perceived 

ambiguity explicitly in the rulemaking record, the EPA assured that the correct meaning of that 

provision should be evident from the record, should any question concerning its meaning arise in 

a future dispute. 

Finally, the EPA notes that while it is possible to reflect interpretive letters in the Code of 

Federal Regulations (CFR) or incorporate them into the regulatory text of the CFR in appropriate 

circumstances, there is no requirement to do so in all actions, and there are other ways for the 

public to have a clear understanding of the content of the SIP. First, for each SIP, the CFR 

contains a list or table of actions that reflects the various components of the approved SIP, 

including information concerning the submission of, and the EPA’s action approving, each 

component. With this information, interested parties can readily locate the actual Federal 

Register document in which the EPA will have explained the basis for its approval in detail, 

including any interpretive letters that may have been relied upon to resolve any potential 

ambiguity in the SIP provisions. With this information, the interested party can also locate the 

docket for the underlying rulemaking and obtain a copy of the interpretive letter itself. Thus, if 

there is any debate about the correct reading of the SIP provision, either at the time of the EPA’s 

approval or in the future, it will be possible to ascertain the mutual understanding of the air 

agency and the EPA of the correct reading of the provision in question at the time the EPA 

approved it into the SIP. Most importantly, regardless of whether the content of the interpretive 

letter is reflected in the CFR or simply described in the Federal Register preamble 

accompanying the EPA’s approval of the SIP submission, this mutual understanding of the 

correct reading of that provision upon which the EPA relied will be the reading that governs, 

should that later become an issue. 
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The EPA notes that the existence of, or content of, an interpretive letter that is part of the 

basis for the EPA’s approval of a SIP submission is in reality analogous to many other things 

related to that approval. Not everything that may be part of the basis for the SIP approval in the 

docket—including the proposal or final preambles, the technical support documents, responses to 

comments, technical analyses, modeling results, or docket memoranda—will be restated 

verbatim, incorporated into, or referenced in the CFR. These background materials remain part 

of the basis for the SIP approval and remain available should they be needed in the future for any 

purpose. To the extent that there is any question about the correct interpretation of an ambiguous 

provision in the future, an interested party will be able to access the docket to verify the correct 

meaning of SIP provisions. 

With regard to the Petitioner’s concern that either actual or alleged ambiguity in a SIP 

provision could impede an effective enforcement action, the EPA believes that its current process 

for evaluating SIP submissions and resolving potential ambiguities, including the reliance on 

interpretive letters in appropriate circumstances with correct documentation in the rulemaking 

action, minimizes the possibility for any such ambiguity in the first instance. To the extent that 

there remains any perceived ambiguity, the EPA concludes that regulated entities, regulators, the 

public, and ultimately the courts, have recourse to use the administrative record to shed light on 

and resolve any such ambiguity as explained earlier in this document. 

The EPA emphasizes that it is already the Agency’s practice to assure that any 

interpretive letters are correctly and adequately reflected in the Federal Register and are included 

in the rulemaking docket for a SIP approval. Should the Petitioner or any other party have 

concerns about any ambiguity in a provision in a SIP submission, the EPA strongly encourages 

that they bring this ambiguity to the Agency’s attention during the rulemaking action on the SIP 
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submission so that it can be addressed in the rulemaking process and properly reflected in the 

administrative record. Should an ambiguity come to light later, the EPA encourages the 

Petitioner or any other party to bring that ambiguity to the attention of the relevant EPA Regional 

Office. If the Agency agrees that there is ambiguity in a SIP provision that requires clarification 

subsequent to final action on the SIP submission, then the EPA can work with the relevant air 

agency to resolve that ambiguity by various means. 

D. Response to Comments Concerning Reliance on Interpretive Letters in SIP Revisions 

The EPA received relatively few comments, both supportive and adverse, concerning the 

Agency’s overarching decision to deny the Petition with respect to this issue. For clarity and ease 

of discussion, the EPA is responding to these comments, grouped by whether they were 

supportive or adverse. 

1. Comments that supported the EPA’s interpretation of the CAA to allow reliance on 

interpretive letters to clarify ambiguities in state SIP submissions. 

Comment: A number of state and industry commenters agreed with the EPA that the use 

of interpretive letters to clarify perceived ambiguity in the provisions in a SIP is a permissible, 

and sometimes necessary, approach to approving SIP submissions under the CAA when done 

correctly. Those commenters who supported the EPA’s proposed action on the Petition did not 

elaborate upon their reasoning, but generally supported it as an efficient and reasonable approach 

to resolve ambiguities. 

Response: The EPA agrees with the commenters who expressed support of the proposal 

based on practical considerations such as efficiency. These commenters did not, however, base 

their support for the proposed action on the EPA’s interpretation of the CAA in the February 

2013 proposal, nor did they acknowledge the parameters that the EPA itself articulated 
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concerning the appropriate situations for such reliance and the process by which such reliance is 

appropriate. Thus, the EPA reiterates that reliance on interpretive letters to resolve ambiguities or 

perceived ambiguities in SIP submissions must be weighed by the Agency on a case-by-case 

basis, and such evaluation is dependent upon the specific facts and circumstances present in a 

specific SIP action and would follow the process described in the proposal. 

2. Comments that opposed the EPA’s interpretation of the CAA to allow reliance on 

interpretive letters to clarify ambiguities in state SIP submissions. 

Comment: Other commenters disagreed with the EPA’s proposed response to the Petition 

on this issue. One commenter opposed the Agency’s reliance on interpretive letters under any 

circumstances and did not draw any factual or procedural distinctions between situations in 

which this approach might or might not be appropriate or correctly processed. This commenter 

argued that citizens should not be required “to sift through a large and complex rulemaking 

docket in order to figure out the meaning and operation of state regulations.” The commenter 

asserted that simply as a matter of “good government,” all state regulations approved as SIP 

provisions should be clear and unambiguous on their face. This commenter also expressed 

concern that courts could not or would not accord legal weight to interpretive letters created after 

state regulations were adopted and submitted to the EPA, or after the EPA’s approval of the SIP 

submission occurred, and would view such letters as post hoc interpretations of no probative 

value. Another commenter added its view that reliance on interpretive letters is appropriate only 

when affected parties have the right to comment on the interpretive letters and the EPA’s 

proposed use of them during the rulemaking in which the EPA relies on such letters to resolve 

ambiguities and before the Agency finally approves the SIP revision. 
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Response: As a general matter, the commenter opposing the EPA’s reliance on 

interpretive letters in any circumstances because citizens would be required “to sift through” the 

docket did not provide specific arguments regarding the EPA’s interpretation of the statute as 

stated in the February 2013 proposal. Consistent with the EPA’s interpretation of the CAA, and 

as explained earlier in this notice, the EPA agrees with the core principle that the language of 

regulations in SIPs that pertain to SSM events should be clear and unambiguous. A commenter 

argued that “a fundamental principle of good government is making sure that all people know 

what the applicable law is. Having the applicable law manifest in a letter sitting in a filing 

cabinet in one office clearly does not qualify as good government.” The EPA generally agrees on 

this point as well. As explained earlier in this notice, the EPA allows the use of interpretive 

letters to clarify perceived ambiguity in the provisions of a SIP submission only when used 

correctly, with adequate documentation in both the Federal Register and the docket for the 

underlying rulemaking action. Section VI.B of this notice explains how interested parties can use 

the list or table of actions that appears in the CFR and that reflects the various components of the 

approved SIP, to identify the Federal Register document wherein the EPA has explained the 

basis for its decision on any individual SIP provision. As such, the EPA does not envision a 

scenario whereby a citizen or a court would be unable to determine how the air agency and the 

EPA interpreted a specific SIP provision at the time of its approval into the SIP. Assuming there 

is any ambiguity in the provision, the mutual understanding of the state and the EPA as to the 

proper interpretation of that provision would be clear at the time of the approval of the SIP 

revision, as reflected in the Federal Register document for the final rule and the docket 

supporting that rule, which should answer any question about the correct interpretation of the 

term. 
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The same commenter also questioned whether “courts can or will give any legal weight 

to interpretative letters created after state regulations are adopted or SIP approvals occurred, in 

the face of industry defendant arguments that the SIP provisions do not accord with those post 

hoc interpretive letters.” This commenter asserted that by not requiring all interpretations of the 

SSM provisions in the “unambiguous language of the SIPs,” the EPA is accepting “great legal 

uncertainty” as to whether judges will consider interpretive letters in enforcement actions. As a 

preliminary matter, as explained earlier in this notice, this action does not apply to “post hoc” 

interpretive letters, i.e., to situations where a state would submit an interpretive letter after the 

EPA’s approval of the SIP. Through this action the EPA is confirming its view that it may use 

interpretive letters to clarify ambiguous SIP provisions only when those letters were submitted to 

the EPA during the evaluation of the SIP submission and before final approval of the SIP 

revision and were included in the final rulemaking docket and explicitly discussed in the Federal 

Register document announcing such final action. 

In addition, as explained earlier in this notice, once the EPA approves a SIP revision, it 

becomes part of the state’s SIP identified in the CFR and thus becomes a federally enforceable 

regulation. In cases where the substance of the interpretive letter is provided in the CFR itself, 

either by copying the interpretation verbatim into the regulatory text or by incorporating the 

letter by reference, courts need not look further for the state and the Agency’s agreed upon 

interpretation. The EPA’s interpretation will be clearly reflected in the CFR. The EPA 

recognizes that actual or perceived regulatory ambiguity may become an issue in instances where 

the interpretive letter is reflected in the preamble to the final rulemaking but is not copied or 

incorporated by reference in the CFR text itself. It is important to note, however, that once 

included in the preamble to the final rule, the air agency’s interpretation of the SIP provision, as 
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reflected in the interpretive letter, becomes the EPA’s promulgated interpretation as well. While 

the EPA recognizes that an agency’s preamble guidance generally does not have the binding 

force of an agency’s regulations, courts do view it as informative in understanding an agency’s 

interpretation of its own regulation,122 and courts accord an agency’s interpretation of its own 

regulations a “‘high level of deference,’ accepting it ‘unless it is plainly wrong.’”123 When 

reviewing a purportedly ambiguous agency regulation, courts have found that the agency’s 

interpretation of its own regulation is “controlling unless ‘plainly erroneous or inconsistent with 

the regulation.’”124 Based on these settled legal principles, the EPA would expect a court in an 

enforcement action to look not only to the text of the regulation at issue but also to the preamble 

to the final rule. The preamble would contain an explanation of any interpretive letter from the 

state upon which the EPA relied in order to interpret any ambiguous SIP provisions.125 As such, 

the EPA disagrees that it is “accepting an unreasonable amount of legal uncertainty” in future 

enforcement actions by allowing the use of interpretive letters to clarify SIP provisions where 

such letters are specifically discussed in the final rulemaking. The EPA reiterates that reliance on 

such interpretive letters is not appropriate in all circumstances, such as instances in which the 

 

122 See, e.g., Howmet Corp. v. EPA, 614 F.3d 544, 552 (D.C. Cir. 2010) (using preamble 

guidance to interpret an ambiguous regulatory provision); Wyo. Outdoor Council v. U.S. Forest 

Serv., 165 F.3d 43, 53 (D.C. Cir. 1999) (“Although the preamble does not ‘control’ the meaning 

of the regulation, it may serve as a source of evidence concerning contemporaneous agency 

intent.”). 

123 Howmet at 549 (quoting Gen Elec. Co. v. EPA, 53 F.3d 1324, 1327 (D.C. Cir. 1990)). 

124 Auer v. Robbins, 519 U.S. 452, 461 (1997) (quoting Robertson v. Methow Valley Citizens 

Council, 490 U.S. 332, 359 (1989)). 

125 Indeed, the APA requires agencies to “incorporate in the rules adopted a concise general 

statement of their basis and purpose,” 5 U.S.C. 553(c), often referred to as the regulatory 

preamble. It would not make sense for a court to attempt to interpret the text of a regulation 

independently from its statutorily mandated statement of basis and purpose. 
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state’s SIP submission is so significantly ambiguous that it is necessary to request that the state 

revise the regulatory text before the EPA can approve it into the SIP. 

Finally, a commenter stated its view that reliance on interpretive letters may be 

appropriate, but only when affected parties have the right to comment on the letter and the EPA’s 

reliance on it during the rulemaking in which the letter is relied upon. The EPA has explained 

earlier in this notice the proper circumstances under which such reliance may be appropriate and 

the proper process to be followed when reliance upon such letters is appropriate, but the EPA 

also notes that the process does not require that the letters always be made available for public 

comment. As explained earlier in this notice, the EPA makes every attempt to identify 

ambiguities in state-submitted SIPs and requests states to submit interpretive letters to explain 

any ambiguities, before putting the proposed action on the SIP submission out for public notice 

and comment. On occasion, however, ambiguous provisions may inadvertently remain and are 

not identified until the notice and comment period has begun. As explained earlier in this notice, 

sometimes these ambiguities are so significant that the EPA requires the state to resubmit its SIP 

submission altogether, which would entail another notice-and-comment period. When the EPA 

does not deem the ambiguity to be so significant as to warrant a revision to the state’s regulatory 

text in the SIP submission, the Agency believes that resolution of the ambiguity through the 

submission of an interpretive letter, which then is incorporated into the EPA’s action, reflected in 

the administrative record and memorialized as the proper intended reading of the provision, is 

appropriate. 

This approach comports with well-established principles applicable to notice-andcomment rulemaking generally. One purpose of giving interested parties the opportunity to 

comment is to provide these parties the opportunity to bring areas of potential ambiguity in the 
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proposal to an agency’s attention so that the concerns may be addressed before the agency takes 

final action. If the APA did not allow the agency to consider comments and provide clarification 

when issuing its final action as necessary, this purpose would be defeated. Courts have held that 

so long as a final rule is a “logical outgrowth” of the proposed rule, adequate notice has been 

provided.126 It is the EPA’s practice to neither require a state to resubmit a SIP submission nor 

repropose action on the submission, so long as the clarification provided in the interpretive letter 

is a logical outgrowth of the proposed SIP provision. If an interested party believes that the EPA 

is incorrect in not requiring the state to revise its SIP submission or that the EPA should 

repropose action on a submission, including the clarification provided by the interpretive letter in 

the plain language of the SIP submission itself, that party does have recourse. The APA gives 

that party the opportunity to petition the EPA for rulemaking to reconsider the decision under 5 

U.S.C. 553(e). For these reasons, the EPA believes that its process for using interpretive letters to 

clarify SIP provisions, as articulated in this rulemaking, is appropriate. 

VII. Clarifications, Reiterations and Revisions to the EPA’s SSM Policy 

A. Applicability of Emission Limitations During Periods of SSM 

1. What the EPA Proposed 

In the February 2013 proposal, the EPA reiterated its longstanding interpretation of the 

CAA that SIP provisions cannot include exemptions from emission limitations for excess 

emissions during SSM events. This has been the EPA’s explicitly stated interpretation of the 

CAA with respect to SIP provisions since the 1982 SSM Guidance, and the Agency has 

reiterated this important point in the 1983 SSM Guidance, the 1999 SSM Guidance and the 2001 

 

126 See, e.g., Shell Oil Co., 950 F.2d 741; NRDC v. Thomas, 838 F.2d 1224 (D.C. Cir. 1988); 

South Terminal Corp. v. EPA, 504 F.2d 646. 
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SSM Guidance. In accordance with CAA section 302(k), SIPs must contain emission limitations 

that “limit the quantity, rate, or concentration of emissions of air pollutants on a continuous 

basis.” Court decisions confirm that this requirement for continuous compliance prohibits 

exemptions for excess emissions during SSM events.127 

2. What is Being Finalized in This Action 

For the reasons explained in the February 2013 proposal, in the background 

memorandum supporting that proposal and in the EPA’s responses to comments in this notice, 

the EPA interprets the CAA to prohibit exemptions for excess emissions during SSM events in 

SIP provisions. This interpretation has long been reflected in the SSM Policy. The EPA 

acknowledges, however, that both states and the Agency have failed to adhere to the CAA 

consistently with respect to this issue in some instances in the past, and thus the need for this SIP 

call action to correct the existing deficiencies in SIPs. In order to be clear about this important 

point on a going-forward basis, the EPA is reiterating that emission limitations in SIP provisions 

cannot contain exemptions for emissions during SSM events. 

As summarized in the comment-by-comment responses that follow, many commenters 

wrongly asserted that the EPA declared in the February 2013 proposal that all emission 

limitations in SIPs must be established as numerical limitations, or must be set at the same 

numerical level at all times. The EPA did not take this position. In the case of section 

110(a)(2)(A), the statute does not include an explicit requirement that all SIP emission 

 

127 See, e.g., Sierra Club v. EPA, 551 F.3d 1019, 1021 (D.C. Cir. 2008) (interpreting the 

definition of emission limitation in section 302(k) and section 112); Mich. Dep’t of Envtl. 

Quality v. Browner, 230 F.3d 181 (6th Cir. 2000) (upholding disapproval of SIP provisions 

because they contained exemptions applicable to SSM events); US Magnesium, LLC v. EPA, 690 

F.3d 1157, 1170 (10th Cir. 2012) (upholding the EPA’s issuance of a SIP call to a state to correct 

SSM-related deficiencies). 
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limitations must be expressed numerically. In practice, it may be that numerical emission 

limitations are the most appropriate from a regulatory perspective (e.g., to be legally and 

practically enforceable) and thus the limitation would need to be established in this form to meet 

CAA requirements. The EPA did not, however, adopt the absolutist position ascribed to it by 

commenters, i.e., that SIP emission limitations must always be expressed only numerically and 

must always be set at the same numerical level during all modes of source operation. 

The EPA notes that some provisions of the CAA that govern standard-setting limit the 

EPA’s own ability to set non-numerical standards.128 Section 110(a)(2)(A) does not contain 

comparable explicit limits on non-numerical forms of emission limitation. Presumably, however, 

some commenters misunderstood the explicit statutory requirement for emission limitations to be 

“continuous” as a requirement that states must literally establish SIP emission limitations that 

would apply the same precise numerical level at all times. Evidently these commenters did not 

consider the explicit recommendations that the EPA made in the February 2013 proposal 

concerning creation of alternative emission limitations in SIP provisions that states may elect to 

apply to sources during startup, shutdown or other specifically defined modes of source 

operation.129 As many of the commenters acknowledged, the EPA itself has recently 

promulgated emission limitations in NSPS and NESHAP regulations that impose different 

numerical levels during different modes of source operation or impose emission limitations that 

are composed of a combination of a numerical limitation during some modes of operation and a 

 

128 See, e.g., CAA section 112(h)(1) (authorizing design, equipment, work practice, or other 

operational emission limitations under certain conditions); 40 CFR 51.308(e)(1)(iii) (regulations 

applicable to regional haze plans). 

129 See February 2013 proposal, 78 FR 12459 at 12478 (February 22, 2013) (the recommended 

criteria for consideration in creation of SIP provisions that apply during startup and shutdown). 
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specific technological control requirement or work practice requirement during other modes of 

operation. In light of the court’s decision in Sierra Club v. Johnson, the EPA has been taking 

steps to assure that its own regulations impose emission limitations that apply continuously, 

including during startup and shutdown, as required. 

Regardless of the reason for the commenters’ apparent misunderstanding on this point, 

many of the commenters used this incorrect premise as a basis to argue that “continuous” SIP 

emission limitations may contain total exemptions for all emissions during SSM events. 

Therefore, in this final action the EPA wishes to be very clear on this important point, which is 

that SIP emission limitations: (i) do not need to be numerical in format; (ii) do not have to apply 

the same limitation (e.g., numerical level) at all times; and (iii) may be composed of a 

combination of numerical limitations, specific technological control requirements and/or work 

practice requirements, with each component of the emission limitation applicable during a 

defined mode of source operation. It is important to emphasize, however, that regardless of how 

the air agency structures or expresses a SIP emission limitation—whether solely as one 

numerical limitation, as a combination of different numerical limitations or as a combination of 

numerical limitations, specific technological control requirements and/or work practice 

requirements that apply during certain modes of operation such as startup and shutdown—the 

emission limitation as a whole must be continuous, must meet applicable CAA stringency 

requirements and must be legally and practically enforceable.130 

 

130 The EPA notes that CAA section 123 explicitly prohibits certain intermittent or supplemental 

controls on sources. In a situation where an emission limitation is continuous, by virtue of the 

fact that it has components applicable during all modes of source operation, the EPA would not 

interpret the components that applied only during certain modes of operation, e.g., startup and 

shutdown, to be prohibited intermittent or supplemental controls. 
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Another apparent common misconception of commenters was that SIP provisions may 

contain exemptions for emissions during SSM events, so long as there is some other generic 

regulatory requirement of some kind somewhere else in the SIP that coincidentally applies 

during those exempt periods. The other generic regulatory requirements most frequently referred 

to by commenters are “general duty” type requirements, such as a general duty to minimize 

emissions at all times, a general duty to use good engineering judgment at all times, or a general 

duty not to cause a violation of the NAAQS at any time. To the extent that such other generalduty requirement is properly established and legally and practically enforceable, the EPA would 

agree that it may be an appropriate separate requirement to impose upon sources in addition to 

the (continuous) emission limitation. The EPA itself imposes separate general duties of this type 

in appropriate circumstances.131 The existence of these generic provisions does not, however, 

legitimize exemptions for emissions during SSM events in a SIP provision that imposes an 

emission limitation. 

In accordance with the definition of section 302(k), SIP emission limitations must be 

continuous and apply at all times. SIP provisions may be composed of a combination of 

numerical limitations, specific technological control requirements and/or work practice 

requirements, but those must be components of a continuously applicable SIP emission 

limitation. In addition, the SIP emission limitation must meet applicable stringency requirements 

during all modes of source operation (e.g., be RACT for stationary sources located in a 

nonattainment area) and be legally and practically enforceable. General-duty requirements that 

 

131 See, e.g., “Oil and Natural Gas Sector: New Source Performance Standards and National 

Emission Standards for Hazardous Air Pollutants Reviews; Final rule,” 77 FR 49489 at 49570, 

49586 (August 16, 2012) (added general standards to apply at all times). 
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are not clearly part of or explicitly cross-referenced in a SIP emission limitation cannot be 

viewed as a component of a continuous emission limitation. Even if clearly part of or explicitly 

cross-referenced in the SIP emission limitation, however, a given general-duty requirement may 

not be consistent with the applicable stringency requirements for that type of SIP provision 

during startup and shutdown. The EPA’s recommendations for developing appropriate 

alternative emission limitations applicable during certain modes of source operation are 

discussed in section VII.B.2 of this notice. In general, the EPA believes that a legally and 

practically enforceable alternative emission limitation applicable during startup and shutdown 

should be expressed as a numerical limitation, a specific technological control requirement or a 

specific work practice requirement applicable to affected sources during specifically defined 

periods or modes of operation. 

3. Response to Comments 

The EPA received a substantial number of comments, both supportive and adverse, 

concerning the issue of exemptions in SIP provisions for excess emissions during SSM events. 

Many of these comments raised the same core issues, albeit using slight variations on the 

arguments or variations on the combination and sequence of arguments. For clarity and ease of 

discussion, the EPA is responding to these comments grouped by issue. 

a. Comments that the EPA’s proposed action on the Petition is incorrect because 

some of the Agency’s own regulations contain exemptions for emissions during SSM events. 

Comment: Many commenters argued that the EPA is misinterpreting the CAA to 

preclude SIP provisions with exemptions for emissions during SSM events because some of the 

Agency’s own existing NSPS and NESHAP rules contain such exemptions. Some commenters 

provided a list of existing NSPS or NESHAP standards that they claimed currently contain 
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exemptions for emissions during SSM events. Commenters also noted that the NSPS general 

provisions at 40 CFR 60.11(d) excuse noncompliance with many NSPS during periods of startup 

and shutdown. Other commenters asserted that the EPA’s interpretations in the February 2013 

proposal are inconsistent with its longstanding interpretation of the Act because the EPA itself 

has a long history of adopting exceptions to numerical emission limitations for emissions during 

SSM events, citing to the NSPS general provisions at 40 CFR 60.8, the NSPS for Fossil-FuelFired Steam Generators and for Electric Utility Steam Generating Units (40 CFR part 60, 

respectively subparts D and Da) and the NSPS for Industrial-Commercial-Institutional Steam 

Generating Units and for Small Industrial-Commercial-Institutional Steam Generating Units (40 

CFR part 60, respectively subparts Db and Dc). Commenters claimed that recent revisions to 40 

CFR subpart Da excluded periods of startup and shutdown from new PM standards. The 

commenters pointed to these facts or alleged facts as evidence that the EPA is interpreting the 

term “emission limitation” or other provisions of the statute inconsistently to preclude SSM 

exemptions in SIP provisions. 

Response: Commenters are correct that many of the EPA’s existing NSPS and NESHAP 

standards still contain exemptions from emission limitations during periods of SSM. The 

exemptions in these EPA regulations, however, predated the 2008 issuance of the D.C. Circuit 

decision in Sierra Club v. Johnson, in which the court held that emission limitations must be 

continuous and thus cannot contain exemptions for emissions during SSM events. Likewise, the 

NSPS general provisions in 40 CFR 60.8 that commenters identified as inconsistent also predate 

that 2008 court decision. Although these other EPA regulations that include exemptions for 

emissions during SSM events were not before the court in the Sierra Club case, the EPA’s view 
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is that the legal reasoning of the Sierra Club decision applies equally to these exemptions and 

that the exemptions are thus inconsistent with the CAA. 

Consequently, since the Sierra Club decision, the EPA has eliminated exemptions in 

many existing federal emission limitations as these standards are revised or reviewed pursuant to 

CAA requirements, such as CAA section 112(d)(6) and (f)(2).132 Similarly, the EPA has 

established emission standards that apply at all times, including during SSM events, when 

promulgating new NSPS and NESHAP standards to be consistent with the Sierra Club

decision.133 The EPA recognizes that the NSPS general provisions regulations also include 

exemptions for emissions during SSM events, but in promulgating new NSPS since the Sierra 

Club decision, the EPA has established emission limitations in the new NSPS that apply at all 

times thereby superseding those general provisions. Therefore, the EPA’s action in this 

rulemaking is consistent with other actions that the EPA has taken since the Sierra Club decision 

concerning the issue of SSM exemptions. 

The fact that the EPA has not completed the process of updating its own regulations to 

bring them into compliance with respect to CAA requirements concerning proper treatment of 

emissions during SSM events does not render this SIP call action arbitrary or capricious. The 

existence of a deficiency in an existing EPA regulation that has not yet been corrected does not 

alter the legal requirements imposed by the CAA upon states with respect to SIP provisions. 

 

132 See, e.g., “New Source Performance Standards Review for Nitric Acid Plants; Final rule,” 77 

FR 48433 (August 14, 2012) (example of NSPS emission limitation that no longer includes 

exemption for periods of startup or shutdown). 

133 See, e.g., “Oil and Natural Gas Sector: New Source Performance Standards and National 

Emission Standards for Hazardous Air Pollutants Reviews; Final rule,” 77 FR 49489 (August 16, 

2012) (consistent with Sierra Club v. EPA, the EPA has established standards in both rules that 

apply at all times). 
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Thus, for example, the EPA does not agree with commenters that the continued existence of 

SSM exemptions in the general provisions applicable to the emission limitations in the Agency’s 

own NSPS for Fossil-Fuel-Fired Steam Generators in 40 CFR part 60, subpart D, is evidence that 

exemptions for emissions during SSM events are permitted by the CAA. 

The EPA acknowledges that correction of longstanding regulatory deficiencies by proper 

rulemaking procedures requires time and resources, not only for the EPA but also for states and 

affected sources. Hence, the EPA has elected to proceed via its authority under section 110(k)(5) 

and to provide states with the full 18 months allowed by statute for compliance with this action. 

This SIP call is intended to help assure that state SIP provisions are brought into line with CAA 

requirements for emission limitations, just as the EPA is undertaking a process to update its own 

regulations. 

The EPA also specifically disagrees with the commenters’ implication that 40 CFR 

60.11(d) completely excuses noncompliance during periods of startup and shutdown. Rather, that 

provision imposes a separate affirmative obligation to maintain and operate the affected facility, 

including associated air pollution control equipment, in a manner consistent with good air 

pollution control practices at all times. The existence of this separate duty to minimize emissions, 

however, does not justify or excuse the existence of an exemption for emissions during SSM 

events from the emission limitations of an EPA NSPS. It is a separate obligation that sources 

must also meet at all times. 

The EPA also disagrees with the commenters who argued that the Agency has recently 

created new exemptions for PM emissions during startup and shutdown events in the NSPS for 

Electric Utility Steam Generating Units in 40 CFR part 60, subpart Da. The EPA has not created 

new exemptions for emissions during startup and shutdown. To the contrary, the EPA has taken 
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steps to assure that these regulations are consistent with the statutory definition of emission 

limitation and with the logic of the Sierra Club decision on a going-forward basis. In accordance 

with that decision, the revised emission limitations in subpart Da NSPS apply continuously. In 

revising subpart Da to establish requirements for sources on which construction, modification or 

reconstruction commenced after May 3, 2011, the EPA determined that it was appropriate to 

provide that the exemptions for emissions during SSM events in the General Provisions do not 

apply.134 Although the Sierra Club v Johnson decision specifically addressed the validity of SSM 

exemptions in NESHAP regulations, the EPA concluded that the court’s focus on the definition 

of “emission limitation” in section 302(k) applied equally to any such SSM exemptions in NSPS 

regulations. Thus, for affected sources on which construction, modification or reconstruction 

starts after May 3, 2011, the General Provisions do not provide an exemption to compliance with 

the applicable emission limitations during SSM events. 

For such sources, the emission limitation for PM in 40 CFR 60.42Da(a) imposes a 

numerical level of 0.03 lb/MMBtu that applies at all times except during startup and shutdown 

and specific work practices that apply during startup and shutdown.135 The related emission 

limitation for opacity from such sources in 40 CFR 60.42Da(b) is 20 percent opacity at all times, 

except for one 6-minute period per hour of not more than 27 percent, and it applies at all times 

except during periods of startup and shutdown when the work practices for PM limit opacity. 

 

134 See 40 CFR 60.48Da(a). For affected facilities for which construction, modification, or 

reconstruction commenced after May 3, 2011, the applicable SO2 emissions limit under § 

60.43Da, NOx emissions limit under § 60.44Da, and NOx plus CO emissions limit under § 

60.45Da apply at all times. 

135 The EPA notes that the emission standards for SO2 in 40 CFR 60.43Da and for NOx in 40 

CFR 60.44Da, applicable to sources on which construction, modification or reconstruction 

commenced after May 3, 2011, also apply continuously and contain no exemptions for emissions 

during SSM events. 
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Commenters alleged that the EPA created an “exemption” from the PM emission limitations in 

subpart Da applicable to post-May 3, 2011, affected sources. That is simply incorrect. The 

revised regulations in subpart Da impose a numerical emission limitation that applies at all times 

except during startup and shutdown and impose specific work practice requirements that apply 

during startup and shutdown as a component of the emission limitation. Specifically, 40 CFR 

60.42Da(e)(2) explicitly requires post-May 3, 2011, affected sources to comply with specific 

work practice standards in part 63, subpart UUUUU. The numerical emission limitation and the 

work practice requirement together comprise a continuous emission limitation and there is no 

exemption for emissions during startup and shutdown. The fact that the EPA has established 

different requirements for different periods of operation does not constitute creation of an 

exemption. These emission limitations have numerical limitations that apply during most periods 

and specific technological control requirements or work practice requirements that apply during 

startup and shutdown, but all periods of operation are subject to controls and no periods of 

operation are exempt from regulation. States are similarly able to alter their regulations, in 

response to this SIP call, to provide for emission limitations with different types of controls 

applicable during different modes of source operation, so long as those controls apply at all times 

and no periods are exempt from controls. As explained in section VII.A of this notice, the EPA 

interprets section 110(a)(2)(A) to permit SIP provisions that are composed of a combination of 

numerical limitations, specific technological control requirements and/or work practice 

requirements, so long as the resulting emission limitations are continuous, meet applicable 

stringency requirements (e.g., are RACT for sources in nonattainment areas) and are legally and 

practically enforceable. 
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The EPA also notes that the provisions of 40 CFR 60.42Da(b)(1) do not provide an 

“exemption” from the opacity standard. That section merely provides that the affected sources do 

not need to meet the opacity standard of the NSPS (at any time), if they have installed a PM 

continuous emission monitoring system (PM CEMS) to measure PM emissions continuously 

instead of relying on periodic stack tests to assure compliance with the PM emission limitation. 

One reason for the imposition of opacity standards on sources is to provide an effective means of 

monitoring for purposes of assuring source compliance with PM emission limitations and proper 

operation of PM emission controls on a continuous basis. If a source is subject to a sufficiently 

stringent PM limitation and has opted to install, calibrate, maintain and operate a PM CEMS to 

measure PM emissions, then it is reasonable for the EPA to conclude that an opacity emission 

limitation is not needed for that particular source for those purposes. The direct measurement of 

PM, in conjunction with an appropriately stringent PM emission limitation that applies 

continuously, is an appropriate means to assure adequate control of PM emissions on a 

continuous basis. States evaluating how best to replace impermissible SSM exemptions from 

opacity standards may wish to consider a similar approach, conditioned upon the use of PM 

CEMS and a sufficiently stringent PM emission limitation. 

Finally, the EPA emphasizes that what is at issue in this action is the question of whether 

emission limitations in SIP provisions can include exemptions for emissions during SSM events. 

The EPA is reiterating its longstanding interpretation of the CAA with respect to this question, in 

the process of responding to the Petition, updating its SSM Policy and applying its current 

interpretations of the CAA to the specific SIP provisions at issue in this SIP call action. To the 

extent that commenters intend to point out that the EPA needs to address exemptions for 
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emissions during SSM events in its own existing regulations, the Agency is already aware of that 

need due to recent judicial decisions and is proceeding to correct those regulations in due course. 

b. Comments that the EPA’s proposed action on the Petition is incorrect because the 

Agency has previously allowed the inclusion of exemptions for emissions during SSM events 

through approval of NSPS or NESHAP requirements into SIPs. 

Comment: Commenters asserted that the EPA is being inconsistent because it has 

previously approved SIP submissions that rely on NSPS rules, including the SSM exemptions in 

those existing rules. The commenters argued that the EPA’s current interpretation of the CAA to 

preclude SSM exemptions in SIP provisions is thus at odds with past guidance and practice. 

Response: The EPA disagrees with the argument that past approval of SIP submissions 

that relied upon an NSPS or NESHAP with an SSM exemption is evidence that such exemptions 

are now permissible in SIP provisions. In the 1999 SSM Guidance, the EPA addressed the 

related issue of whether states could create affirmative defenses in SIP provisions that would 

alter or add to the requirements of an existing EPA NSPS or NESHAP.136 At that time, the EPA 

clearly stated that it would be inappropriate for a state to seek to “deviate” from the specific 

requirements of an NSPS or NESHAP when adopting that standard as a SIP provision, stating 

that “[b]ecause EPA set these standards taking into account technological limitations, additional 

exemptions would be inappropriate.” Thus, so long as a state did not alter the requirements of the 

existing NSPS or NESHAP by including additional affirmative defenses or exemptions, the EPA 

indicated that it would approve a SIP submission that included an NSPS or NESHAP. 

 

136 See 1999 SSM Guidance at Attachment p. 3. 
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The commenters’ argument has brought to the EPA’s attention that past guidance on this 

issue is in fact inconsistent with more recent legal developments. At the time of the 1999 SSM 

Guidance, the EPA was still of the belief that its own NSPS and NESHAP regulations could 

legitimately include exemptions for emissions during SSM events. In that light, recommending 

to states that they could rely on an EPA NSPS or NESHAP as an emission limitation in a SIP 

provision so long as they did not alter the NSPS or NESHAP in any fashion was logical. At that 

time, the reasoning was that NSPS and NESHAP standards were technology-based standards 

that, although neither designed nor intended to meet the separate legal requirements for SIP 

provisions, could be used to provide emission reductions creditable in SIPs. Since the 2008 D.C. 

Circuit decision in Sierra Club v. Johnson, however, it is now clear that NSPS and NESHAP 

standards themselves cannot contain such exemptions. The reasoning of the court was that 

exemptions for SSM events are impermissible because they contradict the requirement that 

emission limitations be “continuous” in accordance with the definition of that term in section 

302(k). Although the court evaluated this issue in the context of EPA regulations under section 

112, the EPA believes that this same logic extends to SIP provisions under section 110, which 

similarly must contain emission limitations as defined in the CAA. Section 110(a)(2)(A) requires 

states to have emission limitations in their SIPs to meet other CAA requirements, and any such 

emission limitations would similarly be subject to the definition of that term in section 302(k). 

Accordingly, the EPA concludes that a state should not submit an NSPS or NESHAP for 

inclusion into its SIP as an emission limitation (whether through incorporation by reference or 

otherwise), unless that NSPS or NESHAP does not include an exemption for SSM events or 

unless the state otherwise takes action to exclude the SSM exemption from the standard as part 

of the SIP submission. Because SIP provisions must apply continuously, including during SSM 
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events, the EPA can no longer approve SIP submissions that include any emission limitations 

with such exemptions, even if those emission limitations are NSPS or NESHAP regulations that 

the EPA has not yet revised to make consistent with CAA requirements. Alternatively, states 

may elect to adopt an existing NSPS or NESHAP as a SIP provision, so long as the state 

provision excludes the SSM exemption.137 States may also wish to replace the SSM exemption 

with appropriately developed alternative emission limitations that apply during startup and 

shutdown in lieu of the SSM exemption. Otherwise, the EPA’s approval of the deficient SSM 

exemption provisions into the SIP would contravene CAA requirements for SIP provisions and 

would potentially result in misinterpretation or misapplication of the standards by regulators, 

regulated entities, courts and members of the public. The EPA emphasizes that the inclusion of 

an NSPS or NESHAP as an emission limitation in a state’s SIP is different and distinct from 

reliance on such standards indirectly, such as sources of emission reductions that may be taken 

into account for SIP planning purposes in emissions inventories or attainment demonstrations. 

For these uses, states may continue to rely on EPA NSPS and NESHAP regulations, even those 

that have not yet been revised to remove inappropriate exemptions, in accordance with the 

requirements applicable to those SIP planning functions. 

c. Comments that the EPA is misinterpreting the Sierra Club case because it applies 

only to MACT regulations and not to SIP provisions. 

 

137 Under CAA section 116, states have the explicit general authority to regulate more stringently 

than the EPA. Indeed, under section 116 states can regulate sources subject to EPA regulations 

promulgated under section 111 or section 112 so long as they do not regulate them less 

stringently. According, the EPA believes that states may elect to adopt EPA regulations under 

section 111 or section 112 as SIP provisions and expressly eliminate the exemptions for 

emissions during SSM events. 
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Comment: Many commenters claimed that the EPA incorrectly applies the holding in the 

Sierra Club decision to preclude exemptions for emissions during SSM events in SIP provisions 

and that the Sierra Club decision does not apply in this context. The commenters argued that the 

Sierra Club decision was directly dependent on the structure of CAA section 112 and cannot be 

extended to the different regulatory structure that governs SIPs under CAA section 110. 

The commenters further contended that in the SIP context, the underlying air quality 

pollution control requirement for SIPs is to attain NAAQS and no specific level of stringency is 

required, unlike section 112, and Congress gave states broad discretion in the design of their 

SIPs. Commenters asserted that the Sierra Club decision held only that the general-duty 

requirement in the section 112 regulations did not meet the stringency requirements of CAA 

section 112 and that this holding does not apply in the SIP context because in the SIP context no 

specific level of stringency is required. 

Commenters also asserted that a general-duty requirement is an appropriate alternative 

standard for SSM events in the SIP context because CAA sections 302(k) and 110(a)(2)(A) give 

states broad authority to develop the mix of controls necessary and appropriate to implement the 

NAAQS. Other commenters contended that the Sierra Club decision does not preclude states 

from constructing a compliance regime that uses multiple methods to limit emissions as long as 

the overall compliance regime to minimize emissions is enforceable. 

Commenters also suggested that the decision in Kamp v. Hernandez relied upon in the 

Sierra Club case affirmed EPA’s approval of a state emission limitation in a SIP that specifically 

allowed and even expected a certain number of annual exceedances of the emission limit.138

 

138 752 F.2d 1444 (9th Cir. 1985). 
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Some commenters argued that the Sierra Club decision should not be read to impose a 

“continuous emissions limitation” requirement and that to the extent it does, it was incorrectly 

decided. 

Response: The EPA disagrees that the court’s decision in Sierra Club v. Johnson has no 

relevance to this action. Of course that decision specifically addressed the validity of exemptions 

for emissions during SSM events in the Agency’s own regulations promulgated under section 

112. Naturally, that decision turned, in part, on the specific provisions of section 112 and the 

specific arguments that each of the litigants raised in that case. However, the decision also turned 

in large part on the explicit statutory definition of the term “emission limitation” in section 

302(k), which requires such limitations to be “continuous.” 

In that litigation, the EPA itself had argued that the exemptions from the otherwise 

applicable MACT standards during SSM events were consistent with CAA requirements because 

the MACT standards and the separate “general duty” requirements “together form an 

uninterrupted, i.e., continuous” emission limitation, because either the numerical limitation or the 

general duty applied at all times.139 The Sierra Club court rejected this argument, in part because 

the general duty that EPA required sources to meet during SSM events was not itself consistent 

with section 112(d) and the EPA did not purport to act under section 112(h). Thus, the EPA 

agrees that the court in Sierra Club explicitly found that the SSM exemption in EPA’s NESHAP 

general provision rules violated the CAA because the general duty to minimize emissions was 

not a section 112(d)-compliant standard and had not been justified by the EPA as a 112(h)-

compliant standard. The court reasoned that when sections 112 and 302(k) are read together, 

 

139 See 551 F.3d 1019, 1026 (D.C. Cir. 2008). 
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there must be a continuous section 112-compliant standard. It is important to note that if the 

otherwise applicable numerical MACT standards had themselves applied at all times consistent 

with section 302(k), then there would have been no question that they were in fact continuous. 

The EPA has concluded that the reasoning of the Sierra Club decision is correct and 

further supports the Agency’s interpretations of the CAA with respect to SIP provisions. As 

explained in the February 2013 proposal, the EPA’s longstanding SSM guidance has interpreted 

the CAA to prohibit exemptions for emissions during SSM events since at least 1982. The EPA 

has long explained that exemptions for emissions during SSM events are not permissible in SIP 

provisions, because they interfere with attainment and maintenance of the NAAQS, protection of 

PSD increments and improvement of visibility, and because they are inconsistent with the 

enforcement structure of the CAA. The EPA also noted that the definition of emission limitation 

in section 302(k) was part of the basis for its interpretation concerning SIP provisions.140 In the 

February 2013 proposal, the EPA explained that the Sierra Club court’s emphasis on the 

definition of the term emission limitation in section 302(k) further bolsters the Agency’s basis 

for interpreting the CAA to preclude such exemptions in SIP provisions. In other words, under 

the CAA and the court’s decision, emission limitations in SIP provisions as well as in NSPS and 

NESHAP regulations must be continuous, although they can impose different levels or forms of 

control during different modes of source operation. 

The EPA also disagrees with the argument that the Sierra Club decision does not apply 

because section 110, unlike section 112, does not impose any specific level of “stringency” for 

SIP provisions. That is incorrect. In accordance with section 110(a)(1), states are required to 

 

140 See 1999 SSM Guidance at 2, footnote 1 (citing the section 302(k) definition of emission 

limitations and emission standards). 
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have SIPs that provide for attainment, maintenance and enforcement of the NAAQS in general. 

Pursuant to section 110(a)(2), states are required to have SIP provisions that meet many specific 

procedural and substantive requirements, including but not limited to, the explicit requirements 

of section 110(a)(2)(A) for emission limitations necessary to meet other substantive CAA 

requirements. In addition, however, states must have SIP provisions that collectively meet a host 

of other statutory requirements that also impose more specific stringency requirements. Merely 

by way of example, section 110(a)(2)(I) requires states with nonattainment areas to have SIP 

provisions that collectively meet part D requirements.141 In turn, the different subparts of part D 

applicable to each NAAQS impose many requirements that require emission limitations in SIPs 

that meet various levels of stringency. Again, merely by way of example, states with 

nonattainment areas for PM under part D subpart 4 must have SIPs that include emission 

limitations that meet either the RACM and RACT level of stringency (if the nonattainment area 

is classified Moderate) or meet the BACM and BACT level of stringency (if the area is classified 

Serious).142 There are similar requirements for states to impose emission limitations that must 

meet various levels of stringency for each of the NAAQS. Likewise, states must impose SIP 

emission limitations that meet BART and reasonable progress levels of stringency for regional 

haze program purposes143 and must ensure that emission limitations meet BACT or LAER levels 

of stringency for nonattainment NSR or PSD permitting program purposes.144 The EPA agrees 

that states have broad discretion to devise SIP provisions under section 110, but states 

 

141 Sections 171–193 of CAA title I comprise part D. 

142 See CAA section 172(c)(2) (generally applicable attainment plan requirements including 

RACM and RACT); CAA section 189(a)(1) (requirements for areas classified Moderate); section 

189(b) (requirements for areas classified Serious). 

143 See CAA section 169A(b)(2)(A). 

144 See CAA section 165(a)(4) and CAA section 173(a)(2). 
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nevertheless are required to devise SIP provisions that meet applicable statutory stringency 

requirements. In short, the argument that the Sierra Club decision is not germane because there 

are no comparable “stringency” requirements applicable to SIP provisions is simply in error. 

While it is true that SIP provisions do not need to meet section 112 levels of stringency, they 

must still be continuous under section 302(k) and meet applicable NAAQS, PSD and visibility 

requirements and stringency levels. In short, they cannot contain exemptions for emissions 

during SSM events. 

Finally, the EPA does not agree with the commenters’ view of the significance of the 

reference to the Kamp v. Hernandez decision by the court in the Sierra Club decision. The Kamp

decision upheld the EPA’s approval of a SIP provision that imposed an SO2 emission limitation 

on a specific stationary source.145 To the extent that the commenters believe that the Kamp

decision stands for the principle that SIP emission limitations can be “continuous” even if they 

do not restrict emissions to the same numerical limitation at all times, this point is not in dispute. 

As explained in section VII.A of this document, the EPA agrees with this principle. If, however, 

the commenters believe that the Kamp decision instead indicates that SIP emission limitations 

may contain exemptions, such that no emission standard applies during some mode of source 

operation, then that is simply incorrect. The EPA-approved SIP provision at issue in Kamp did 

not itself allow for a certain number of “exceedances” of the emission limitation each year. The 

state emission limitation rule in that case was developed to ensure attainment and maintenance of 

the then applicable SO2 NAAQS and the approved emission limitation for the source fluctuated 

but was continuous. It was the specifications of the SO2 NAAQS standard that allowed for a 

 

145 753 F.3d 1444, 1452–53 (9th Cir. 1985). 
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certain number of “exceedances” each year. The NAAQS themselves are not “emission 

limitations” governed by section 302(k) and commonly have a statistical “form” that authorizes a 

set number of “exceedances” of the numerical level of the NAAQS before there is a “violation” 

of the NAAQS.146 Thus, the EPA believes that the court in the Sierra Club decision properly 

cited the Kamp case as support for the fundamental proposition that emission limitations must be 

“continuous.” Moreover, the EPA notes that commenters did not address other reported decisions 

in which courts have upheld the Agency’s disapproval of SIP submissions containing SSM 

exemptions.147 

d. Comments that the EPA’s proposed action contradicts a 2009 guidance document 

concerning the effect of the Sierra Club decision on SSM exemptions in existing standards. 

Comment: A number of commenters suggested that the EPA’s February 2013 proposal is 

inconsistent with a memorandum (in fact a public letter) issued by the Agency following the 

Sierra Club decision in which the D.C. Circuit vacated two EPA provisions that exempt sources 

from section 112(d) emission standards during periods of SSM (Kushner letter).148 The 

commenters noted that the Kushner letter explained that many MACT standards have SSM 

exemptions that were not affected by the Sierra Club decision. They argued that the Kushner 

letter should be read to mean that no emission limitations other than the ones explicitly discussed 

 

146 See, e.g., 40 CFR 50.18 (24-hour PM2.5 NAAQS met when 98th-percentile monitored value is 

less than or equal to 35 ug/m3). 

147 See, e.g., Mich. Dep’t of Envtl. Quality v. Browner, 230 F.3d 181 (6th Cir. 2000) (upholding 

disapproval of SIP provisions because they contained exemptions applicable to SSM events); US 

Magnesium, LLC v. EPA, 690 F.3d 1157, 1170 (10th Cir. 2012) (upholding the EPA’s issuance 

of a SIP call to a state to correct SSM-related deficiencies). 

148 See Letter from A. Kushner, Director, Office of Civil Enforcement, EPA/OECA, regarding 

“Vacatur of Startup, Shutdown, and Malfunction (SSM) Exemption (40 C.F.R. §§ 63.6(f)(1) and 

63.6(h)(1)),” July 22, 2009, in the rulemaking docket. 
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within that letter would be affected by the court’s holding that emission limitations under the 

CAA must be continuous. 

Response: The EPA disagrees with these comments for several reasons. First, the 

commenters misinterpret the Kushner letter. The purpose of the Kushner letter was to explain the 

direct and immediate impact of the Sierra Club decision, which vacated the SSM exemption in 

EPA’s NESHAP general provisions regulations. The Kushner letter explained that the vacatur 

would “immediately and directly” affect only the subset of NESHAP source category standards 

that incorporated the general provisions’ exemption by reference, and that contain no other 

regulatory text exempting or excusing, in any way, compliance during SSM events, because only 

the general provisions’ exemption was challenged and before the court in the Sierra Club case. 

However, the Kushner letter clearly stated that the legality of all NESHAP SSM exemption 

provisions was in question and that EPA would examine such provisions in light of the court’s 

decision. Therefore, the commenters’ suggestion that the Kushner letter supports a limited 

reading of the legal reasoning of the Sierra Club case is incorrect. 

Second, the Kushner letter did not explicitly or implicitly address the issue of whether the 

CAA allows exemptions for emissions during SSM events in SIP provisions. That fact is 

unsurprising, in that at the time of the Kushner letter the EPA already had guidance in the SSM 

Policy (issued and reiterated in 1982, 1983, 1999 and 2001) that clearly stated the Agency’s view 

that such exemptions are not permissible in SIP provisions, consistent with CAA requirements. It 

would also have been unnecessary for the Kushner letter discussing the impact of the Sierra Club

decision on NESHAP standards to have mentioned that the statutory definition of emission 

limitation also precludes exemptions for SSM provisions in SIPs. The EPA had already made 

this point explicitly in the 1999 SSM Guidance, when it explained the reasons why such 
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provisions would be contrary to CAA requirements for SIPs.149 Thus, the EPA’s guidance for 

SIP provisions concerning emissions during SSM events had already explicitly articulated that 

provisions with exemptions for SSM events could not be approved pursuant to CAA section 

110(l), because that would interfere with a fundamental requirement of the CAA, i.e., the 

definition of “emission limitation” in section 302(k). 

Finally, the EPA disagrees that the Kushner letter could override the applicability of the 

logic of the Sierra Club decision to SIP provisions, even if the Agency had any such intentions. 

The D.C. Circuit’s evaluation of the issue with respect to the EPA’s own regulations was 

premised not solely upon the particular requirements of section 112 but also more broadly on the 

meaning and specific definition of the term “emission limitation” under the CAA. That definition 

applies to SIP provisions as well as to the EPA’s own regulations. Because the SSM Policy in 

effect at the time of the Sierra Club decision and the time of the Kushner letter already stated 

that EPA interpreted the CAA to prohibit SIP provisions that exempt emissions during SSM 

events, there would have been no need for the Kushner letter to speak to this issue.150 

e. Comments that the EPA’s proposed action on the Petition is incorrect because the 

Agency’s recent MATS rule and Area Source Boiler rule regulations contain exemptions for 

emissions during SSM events. 

 

149 See 1999 SSM Guidance at 2, footnote 1. 

150 See, e.g., 1999 SSM Guidance, Attachment at 1 (“any provision that allows for an automatic 

exemption for excess emissions is prohibited”). 
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Comment: Many commenters asserted that the EPA’s February 2013 proposed action to 

find SIP provisions with exemptions for emissions during SSM events to be substantially 

inadequate is arbitrary and capricious because recent Agency NESHAP regulations under section 

112 contain similar exemptions. Commenters pointed to recently promulgated rules such as the 

MATS rule 151 and the Area Source Boiler rule152 as examples of NESHAP regulations that they 

claim contain similar exemptions. According to commenters, the emission limitations in EPA’s 

own MATS rule “allow excess emissions during SSM events,” suggesting that the Agency 

created exemptions for such emissions.153 Other commenters similarly argued that the EPA 

created emission limitations in the Area Source Boiler rule that do not apply “continuously” 

because the numerical limitations do not apply during startup and shutdown.154 In short, these 

commenters argued that the EPA is being arbitrary and capricious because it is holding emission 

limitations in SIPs to a different and higher standard than emission limitations under its own 

NSPS and NESHAP regulations. 

 

151 The mercury and air toxics standards (MATS) rule for power plants regulates emissions from 

new and existing coal- and oil-fired electric utility steam generating units (EGUs) under 40 CFR 

part 63, subpart UUUUU. 

152 The Area Source Boiler rule regulates industrial, commercial and institutional boilers at area 

sources under 40 CFR part 63, subpart JJJJJJ. 

153 See MATS rule, requirements during startup, shutdown and malfunction, 77 FR 9304 at 9370 

(February 16, 2012). 

154 See Area Source Boiler rule, notice of final action on reconsideration, periods of startup and 

shutdown, 78 FR 7487 at 7496 (February 1, 2013). 
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Response: The EPA disagrees with these commenters. The recent EPA rulemaking 

efforts that commenters claim are at odds with EPA’s SIP call are completely consistent with the 

Agency’s action today. First, as explained in the February 2013 proposal, the EPA has not taken 

the position that sources must be subject to SIP emission limitations that are set at the same 

numerical level at all times, or that are expressed as numerical limitations at all times. As the 

EPA stated, “[i]f justified, the state can develop special emission limitations or control measures 

that apply during startup or shutdown if the source cannot meet the otherwise applicable 

emission limitation in the SIP.”155 The EPA’s 1999 SSM Guidance articulated that SIP 

provisions may include alternative emission limitations applicable during startup and shutdown 

as part of a continuously applicable emission limitation when properly developed and otherwise 

consistent with CAA requirements. Moreover, the EPA recommended specific criteria relevant 

to the creation of such alternative emission limitations. The EPA reiterated that guidance in the 

February 2013 proposal and is providing a clarified version of the guidance in this final action. 

This issue is addressed in more detail in section VII.B.2 of this document. 

The EPA also disagrees with the assertion that it is holding state SIP provisions to a 

different standard than its own NSPS and NESHAP regulations. The EPA notes that SIP 

emission limitations and NSPS and NESHAP emission limitations are, of course, designed for 

different purposes (e.g., to meet the NAAQS versus to reduce HAP emissions) and have to meet 

some different statutory requirements (e.g., to be RACM versus be standards that are compliant 

with section 112). However, the EPA understands the commenters’ claim to be more specifically 

that the Agency is applying a different interpretation of the term “emission limitation” and taking 

 

155 See February 2013 proposal, 78 FR 12459 at 12488 (February 22, 2013). 
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a different approach to the treatment of emissions during SSM events in its own regulations, 

even in recent regulations developed subsequent to the Sierra Club decision. The EPA believes 

that this argument reflects a misunderstanding of both the February 2013 proposal and what the 

Agency’s own new regulations contain. 

The MATS rule and the Area Source Boiler rule in fact illustrate how the EPA is creating 

emission limitations that apply continuously, with numerical limitations or combinations of 

numerical limitations and other specific technological control requirements or work practice 

requirements applicable during startup and shutdown, depending upon what is appropriate for the 

source category and the pollutants at issue. For example, in the MATS rule the EPA has 

promulgated regulations that impose emission limitations on various subcategories of sources to 

address HAP emissions. To do so, the EPA developed emission limitations to address the 

relevant pollutants using a combination of numerical emission limitations and work practices. 

The work practice requirements specifically apply to sources during startup and shutdown and 

are thus components of the continuously applicable emission limitations.156 

Similarly, in the Area Source Boiler rule157 the EPA has imposed emission limitations on 

affected sources for PM, mercury and CO. The specific emission limitations that apply vary 

depending upon the subcategory of boiler. The emission limitations include a combination of 

numerical emission limitations and work practice requirements that together apply during all 

 

156 The EPA took final action on a petition for reconsideration concerning the MATS rule and the 

Utility NSPS that made certain revisions related to the emission limitations and work practices 

applicable during startup and shutdown. Those revisions did not, however, alter the basic 

structure of the emission limitations as numerical limitations, or numerical limitations with work 

practice components during startup and shutdown, depending upon the source category and the 

pollutants at issue. See 79 FR 68777 (November 19, 2014). 

157 78 FR 7487 (February 1, 2013). 
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modes of source operation. For some subcategories, the standards that apply during startup and 

shutdown differ from the standards that apply during other periods of operation. This illustrates 

what the EPA considers the correct approach to creating emission limitations: (i) the emission 

limitation contains no exemption for emissions during SSM events; (ii) the component of the 

emission limitation that applies during startup and shutdown is clearly stated and obviously is an 

emission limitation that applies to the source; (iii) the component of the emission limitation that 

applies during startup and shutdown meets the applicable stringency level for this type of 

emission limitation (in this case section 112); and (iv) the emission limitation contains 

requirements to make it legally and practically enforceable. In short, the Area Source Boiler rule 

established emission limitations that apply continuously, in accordance with the requirements of 

the CAA, and consistent with the court’s decision in the Sierra Club decision. States with SIP 

provisions that are deficient because they contain automatic or discretionary exemptions for 

emissions during SSM events may wish to consider the Agency’s own approach when they 

develop SIP revisions in response to this SIP call. 

f. Comments that section 110(a)(2)(A) authorizes states to have SIP provisions with 

exemptions for emissions during SSM events because they are not “emission limitations” and are 

not subject to the requirement to be “continuous.” 

Comment: Section 110(a)(2)(A) requires states to have SIPs that include emission 

limitations for purposes of imposing restrictions on sources of emissions in order to attain and 

maintain the NAAQS and to meet other CAA requirements. Some commenters noted that, in 

addition to “emission limitations,” section 110(a)(2)(A) also explicitly refers to “other control 

measures, means, or techniques.” Unlike the term “emission limitation,” which is defined in 

section 302(k), commenters contended that these “other control[s]” need not be continuous. 
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Accordingly, these commenters argued that emission controls in SIP provisions that either 

contain, or are subject to, SSM exemptions can be viewed merely as examples of these “other 

control measures, means, or techniques” that are validly included in SIPs and that do not have to 

limit emissions from sources on a continuous basis. Specifically, these commenters asserted that 

the plain text of section 110(a)(2)(A) does not require SIPs to include only emission limitations 

but rather requires that SIPs include “emission limitations,” “other control measures, means, or 

techniques,” or a mixture thereof. Furthermore, according to some of these commenters, an 

interpretation of section 110(a)(2)(A) that requires all SIP provisions to be “emission 

limitations,” and thus subject to the requirement that they be continuous, would render the “other 

control” language in the statute superfluous. 

Response: The EPA agrees with the commenters that SIPs do not have to be composed 

solely of numerical emission limitations, that SIPs can contain other forms of controls in addition 

to emission limitations and that certain forms of controls other than emission limitations may not 

need to apply to sources continuously. However, the EPA disagrees with the commenters’ 

conclusion that the mere act of labeling certain SIP provisions as “control measures, means, or 

techniques” rather than as “emission limitations” can be a means to circumvent the requirement 

that emission limitations must regulate sources continuously. To the extent that there is any 

ambiguity in the requirements of section 110(a)(2), it is not reasonable to interpret the statute to 

allow the explicit requirement that emission limitations must be continuous to be negated in this 

fashion. 

As an initial matter, the SIP provisions that contain automatic or discretionary 

exemptions during SSM events at issue in this SIP call excuse compliance with requirements that 

presumably were submitted to the EPA as emission limitations, were intended to limit emissions 
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on a continuous basis or were otherwise included to ensure that the SIP contained continuous 

emission limitations. All of the SIP provisions at issue in this action provide automatic or 

discretionary exemptions from emission limitations that are formulated as restrictions on the 

“quantity, rate, or concentration” of emissions from affected sources, just as section 302(k) 

describes the purpose of an emission limitation. Longstanding EPA regulations applicable to 

SIPs require that states have a control strategy to provide for attainment and maintenance of the 

NAAQS.158 The required “control strategy” is defined to be the combination of measures 

including, but not limited to, “emission limitations,” “emission control measures applicable to in 

use motor vehicles” and “transportation control measures” listed in section 108(f).159 The 

regulatory definition of “emission limitation” applicable to SIP provisions tracks the statutory 

definition of section 302(k) and notably also does not define the term to allow exemptions for 

emissions during SSM events.160 To the EPA’s knowledge, none of the specific SIP provisions 

that contain or that are subject to the automatic or discretionary exemptions at issue in this SIP 

call action were developed by the states with the intention or expectation that absent the 

exemption they would not apply at all times when the source is in operation; i.e., they impose 

restrictions on emissions that were intended to apply continuously when the source is emitting 

pollutants. Logically, the states intended the emission limitations to impose limits that apply 

continuously at all times when the affected sources are emitting pollutants or else there would 

have been no impetus to include any exemptions for emissions during SSM events. 

 

158 See, e.g., 40 CFR 51.100. 

159 See, e.g., 40 CFR 51.100(n). 

160 See 40 CFR 51.100(z). 
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However, even if the EPA were to accept the commenters’ premise arguendo—that 

inclusion of an SSM exemption in a given SIP provision turns “emission limitations” into “other 

control measures, means, or techniques,” this would not be a reasonable reading of the 

requirements of section 110(a)(2)(A) and section 302(k) for several reasons. To the extent that 

either section 110(a)(2)(A) or section 302(k) is ambiguous with respect to this point, the EPA 

does not interpret the CAA to allow exemptions for emissions during SSM events in SIP 

provisions in the way advocated by the commenters. 

First, section 110(a)(2)(A) explicitly requires that SIPs must contain emission limitations 

as necessary to meet various CAA requirements. Section 302(k) requires that such emission 

limitations must limit “the quantity, rate, or concentrations of emissions of air pollutants on a 

continuous basis.” Moreover, section 302(k) reiterates that the term “continuous emission 

limitation” also specifically includes “any requirement relating to the operation or maintenance 

of a source to assure continuous emission reduction.” Lest there be doubt, section 302(m) 

provides a definition for the related term “means of emission limitation” as “a system of 

continuous emissions reduction (including the use of specific technology or fuels with specified 

pollution characteristics).” In the Sierra Club v. Johnson decision, the D.C. Circuit concluded 

that the statutory definition of “emission limitation” in section 302(k) precludes exemptions for 

emissions during SSM events because such exemptions are inconsistent with the requirement for 

continuous controls.161 Given the emphasis that the statute places on the requirement that sources 

be subject to continuous emission controls, and given the emphasis that courts have placed on the 

requirement that sources be subject to continuous controls on their emissions, the EPA believes 

 

161 See Sierra Club v. EPA, 551 F.3d 1019, 1027–28 (citing CAA sections 112(d)(2), 302(k)). 
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that it is illogical that the statutory requirement for continuous controls on sources could be 

subverted merely by the act of labeling a given SIP provision a “control measure” rather than an 

“emission limitation.” The commenters’ argument that if a given SIP provision contains an SSM 

exemption, it is merely a “control measure[], mean[], or technique[]” reduces the explicit 

requirement for continuous controls on emissions to a semantic exercise. 

Second, the EPA believes that the commenters’ reading of the statute to permit SIP 

provisions to contain an SSM exemption by virtue of what it is labeled is obviously incorrect if 

taken to its logical extreme. The commenters’ interpretation of section 110(a)(2)(A) would 

theoretically allow a SIP to contain no emission limitations whatsoever, merely a collection of 

requirements labeled “control measures” so that sources can be excused from having to limit 

emissions on a continuous basis. This result is contrary to judicially approved EPA 

interpretations of prior versions of the CAA as requiring all SIPs to include continuously 

applicable emission limitations and only requiring “other” additional controls “as may be 

necessary” to satisfy the NAAQS.162 Additionally, this result is contrary to legislative history of 

the 1990 Clean Air Act Amendments, which indicates that in slightly revising this portion of 

section 110(a)(2)(A), Congress intended to merely “combine and streamline” previously existing 

 

162 See, e.g., Kennecott Copper Corp. v. Train, 526 F.2d 1149, 1153 (9th Cir. 1975). The current 

version of section 110(a)(2)(A) is admittedly worded differently than the 1970 version. However, 

for purposes of these commenters the critical distinction is not that Congress changed the 

location of the word “necessary” but rather that Congress changed the subject that “necessary” 

modifies—and thus the entire scope of 110(a)(2)(A)—from satisfying the NAAQS to meeting 

“applicable requirements” of the entire CAA. 
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SIP requirements into a single provision, not to vitiate statutory requirements concerning 

emission limitations.163 

Finally, the EPA’s interpretation of the requirements of section 110(a)(2) does not render 

the “other control” language in the statute superfluous as claimed by the commenters. In addition 

to emission limitations, the EPA interprets that section to allow other “control measures, means 

or techniques” as contemplated by the statute. For example, the EPA’s regulations implementing 

SIP requirements explicitly enumerate nine separate types of measures that states may include in 

SIPs.164 This list of nine different forms of potential SIP provisions to reduce emissions varies 

broadly, from measures that “impose emission charges or taxes or other economic incentives or 

disincentives” to “changes in schedules or methods of operation of commercial or industrial 

facilities” to “any transportation control measure including those transportation measures listed 

in section 108(f).” The EPA made clear that this list is not all-inclusive. In addition, the EPA has, 

when appropriate, approved SIP provisions that impose various forms of emissions controls that 

are not, by definition, emission limitations.165 Thus, the commenters are in error in their belief 

that the EPA’s reading of the statute to require that SIPs contain emission limitations that apply 

continuously ignores the other forms of potential measures that section 110(a)(2)(A) authorizes. 

 

163 See, e.g., S. Rept. 101-228, at 20 (noting that the structure of section 110(a)(2)(A) as it 

appears today reflects congressional intent to “combine and streamline” previously existing SIP 

requirements into a single provision). 

164 See 40 CFR 51.100(n). 

165 See, e.g., 71 FR. 7683 (February 14, 2006) (approving as BACM the use of “conservation 

management practices” to control fugitive dust emissions from agricultural sources, including 

techniques that limit emissions only during certain activities or times); 68 FR 56181 

(September 30, 2003) (approving as BACM an “episodic wood burning curtailment” program 

that restricts the use of wood-burning stoves based on predicted particulate matter 

concentrations). 
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Section 110(a)(2) requires SIPs to include enforceable emission limitations and other 

controls “as necessary or appropriate to meet the applicable requirements” of the CAA. 

Regardless of whether commenters’ semantic labeling arguments are valid in the abstract, they 

are not correct with respect to the fundamental CAA requirements for SIPs relating to continuous 

emission limitations. The automatic or discretionary exemptions for emissions during SSM 

events in the SIP provisions at issue in this SIP call authorize exemptions from statutorily 

required emission limitations. To the extent that such a SIP provision would functionally or 

legally exempt sources from regulation during SSM events, the SIP provision fails to be a 

continuously applicable enforceable emission limitation as required by the CAA. The fact that a 

SIP may also contain “other control[s]” as advocated by the commenters does not negate the 

statutory requirement that emission limitations must apply continuously. 

g. Comments that the definition of “emission limitation” in section 302(k) does not 

require that all forms of emission limitations must apply continuously. 

Comment: Section 110(a)(2)(A) requires that SIPs must contain emission limitations, and 

section 302(k) defines the term “emission limitation” to mean a limit on emissions from a source 

that applies continuously. A number of commenters disagreed that section 302(k) requires that 

all “emission limitations” have to be “continuous.” The commenters argued that section 302(k) 

establishes two distinct categories of emission limitations: (1) requirements that “limit[] the 

quantity, rate, or concentration of emissions of air pollutants on a continuous basis, including any 

requirement relating to the operation or maintenance of a source to assure continuous emission 

reduction,” and (2) requirements constituting a “design, equipment, work practice or operational 

standard promulgated under this chapter.” These commenters claimed that only the first 

purported category is emission limitations that must be continuous and that the second purported 
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category is emission limitations that do not need to apply continuously. Accordingly, these 

commenters asserted that SIP provisions that are rendered noncontinuous by inclusion of 

exemptions for emissions during SSM events are still legally valid “emission limitations” 

because they fall within the second category. Other commenters separately contended that under 

section 302(k), SIP provisions imposing requirements “relating to the operation or maintenance 

of sources” do not need to be continuous, unlike those imposing requirements that limit “the 

quantity, rate, or concentration of emissions or air pollutants.” 

Response: The EPA disagrees with the commenters’ view that section 302(k) establishes 

two discrete categories of emission limitations, only one of which must reduce continuous 

emissions on a continuous basis. The EPA acknowledges that the text of section 302(k) is 

ambiguous with respect to this point, but the Agency does not agree with the commenters’ 

interpretation of the statute. The statutory text of section 302(k) begins with a catch-all definition 

of the term “emission limitation” as “a requirement established by the State or the Administrator 

which limits the quantity, rate, or concentration of emissions of air pollutants on a continuous 

basis . . . .”166 The EPA believes that the rest of the first sentence in section 302(k), beginning 

with the word “including,” is best read as a list of examples of types of measures that satisfy this 

general definition. In other words, the remainder of the sentence provide examples of types of 

SIP provisions that could be used to limit emissions on a continuous basis, including any design 

standard, equipment standard, work practice standard or operational standard promulgated under 

the CAA, as well as “any requirement relating to the operation or maintenance of a source to 

assure continuous emission reduction.” However, each of these forms of emission limitation 

 

166 CAA section 302(k). 
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would be required to apply at all times, or be required to apply in combination at all times, in 

order to meet the fundamental requirement that the emission limitation serves to limit emissions 

from the affected sources continuously. Thus, the EPA interprets the term “emission limitation” 

to permit emission limitations that are composed of a combination of numerical limitations, 

technological control requirements and/or work practice requirements, so long as they are 

components of an emission limitation that applies continuously. This interpretation accords with 

statutory context,167 the legislative history regarding the definition of “emission limitation,”168

judicial interpretations of section 302(k)169 and the EPA’s definition of “emission limitation” in 

its SIP regulations.170 Accordingly, the EPA’s interpretation of section 302(k) is reasonable. 

The EPA also disagrees with the commenters who contended that the third clause of 

section 302(k) authorizes exemptions for emissions during SSM events in emission limitations. 

The commenters argued that requirements “relating to the operation or maintenance of sources” 

do not have to be continuous. The EPA believes that this reading of the statute is simply in error, 

because section 302(k) on its face provides that these requirements must “assure continuous 

emission reduction.”171 

 

167 See, e.g., CAA section 302(m) (defining “means of emission limitation” as a “system of 

continuous emission reduction”). 

168 See e.g., H.R. Rep. 95-294, at 92 (1977) (explaining that the definition of “emission 

limitation,” like the definition of “standard of performance,” was intended to “ma[ke] clear that 

constant or continuous means of reducing emissions must be used to meet th[ose] 

requirements”); S. Rep. 95-127, at 94 (explaining that the definition of “emission limitation” was 

intended to “clarify the committee’s view that the only acceptable basic strategy is one based on 

continuous emission control,” rather than “unacceptable” “[i]ntermittent controls or dispersion 

techniques . . . .”). 

169 See, e.g., Sierra Club v. EPA, 551 F.3d 1019, 1027–28 (D.C. Cir. 2008). 

170 See 40 CFR 51.100(n) (defining “emission limitation” as a requirement that limits emissions 

on a continuous basis). 

171 See CAA section 302(k). 
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h. Comments that exemptions or affirmative defenses are not only not prohibited, 

but are actually required by the CAA because they are necessary to make an emission limitation 

“reasonable” or “achievable” for sources that cannot comply during SSM events. 

Comment: Commenters argued that some emission limitations currently in SIPs are only 

“reasonable” or technologically “achievable” because they include exemptions or affirmative 

defenses applicable to emissions during SSM events. According to these commenters, without 

exemptions or affirmative defenses to excuse sources from compliance with the limits during 

SSM events, these emission limitations would not be reasonable or achievable as required by 

law. To support these contentions, commenters cited case law from the early 1970s to argue that 

the CAA requires emission limitations in SIP provisions to include exemptions or affirmative 

defenses for SSM events. 

Response: The EPA agrees that SIP provisions should impose emission limitations that 

are reasonable and achievable by sources, so long as they are also consistent with the applicable 

legal requirements for that type of provision. The EPA acknowledges that that in some cases, 

emission limitations may need to include alternative numerical limitations, technological 

controls or work practices during some modes of operation, such as startup and shutdown. As 

explained in detail in the February 2013 proposal and in this action, the EPA interprets the CAA 

to allow SIP provisions to include different numerical limitations or other control requirements 

as components of a continuously applicable emission limitation, so long as the SIP provision 

meets all other applicable requirements. However, the EPA disagrees with these commenters’ 

conclusions that the need for “reasonable” and “achievable” emission limitations provides a legal 

justification for exemptions or affirmative defenses for excess emissions during SSM events. 
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First, many of the commenters erroneously presupposed that an emission limitation must 

continuously control emissions at the same rate, quantity, or concentration at all times. For 

sources or source categories that cannot comply with otherwise applicable emission limitations 

during certain modes of operation, such as startup and shutdown, the state may elect to develop 

alternative emission limitations applicable during those events as a component of the SIP 

provision. The EPA has provided recommended criteria for states to use in developing 

appropriate alternative emission limitations. Appropriate alternative emission limitations would 

ensure the existence of requirements that limit the quantity, rate or concentration of pollutants 

from the affected sources on a continuous basis, while also providing differing limitations 

tailored specifically to limit emissions during specified modes of source operation. As long as 

those differing limitations are components of a continuously applicable emission limitation that 

meets other applicable substantive requirements (e.g., is RACT for stationary sources in 

nonattainment areas) and that is legally and practically enforceable, then such alternative 

emission limitations are valid. States are not required to create such alternative emission 

limitations, but to do so is an acceptable approach. 

Second, these commenters pointed to no provision of the CAA requiring or allowing 

exemptions or affirmative defenses for SSM events. Instead, they contend that D.C. Circuit 

opinions in Portland Cement Association v. Ruckelshaus172 and Essex Chemical Corp. v. 

Ruckelshaus173 require SIPs to include exemptions for emissions during SSM events. As an 

initial matter, these cases predate amendments to the CAA that expressly defined “emission 

limitation” as a requirement that continuously limits emissions. Furthermore, even accepting 

 

172 486 F.2d 375 (D.C. Cir. 1973). 

173 486 F.2d 427 (D.C. Cir. 1973). 
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these commenters’ interpretations of those cases (which as explained below, EPA does not), any 

purported holdings to that effect have been further eroded by more recent case law from the D.C. 

Circuit and other courts. Most importantly, the Sierra Club v. EPA decision has reiterated that 

emission limitations must apply continuously in order to comply with section 302(k), and the 

logic of NRDC v. EPA decision indicates that affirmative defense provisions are not appropriate 

because they purport to alter the jurisdiction of the courts.174 

In addition to these more recent legal developments, however, the two earlier D.C. 

Circuit cases highlighted by commenters simply did not hold what commenters claim that they 

held. With respect to the Portland Cement Association decision, commenters selectively quoted 

from the case for the proposition that the D.C. Circuit had “acknowledged” that malfunctions are 

an inescapable aspect of industrial life and that EPA must make allowances for malfunctions 

when promulgating standards. The full sentence from the opinion, however, makes clear that the 

D.C. Circuit was merely summarizing the “concern of manufacturers,” not stating the court’s 

own position.175 To the contrary, the EPA believes that Portland Cement stands for the broader 

proposition that a system incorporating flexibility is reasonable and consistent with the overall 

intent of the CAA, and the EPA merely “may” take such flexibility into account.176 As relevant 

to this action, the flexibility provided states to ensure continuous controls by developing 

 

174 See Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008); NRDC v. EPA, 749 F.3d 1055 (D.C. 

Cir. 2014). 

175 Portland Cement Ass’n, 486 F.2d at 398. 

176 Id. at 399. 
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alternative emission limitations is fully consistent with that view of the CAA. SIP provisions that 

include alternative emission limitations provide the sort of “limited safety valve” contemplated 

by the courts that can serve to make SIP emission limitations more achievable without 

authorizing complete exemptions for emissions during SSM events in violation of statutory 

requirements.177 

Commenters also cited Essex Chemical Corp. for the proposition that SSM exemptions 

are necessary to ensure that standards are reasonable. This court decision, however, also did not 

hold that emission limitations must provide exemptions or affirmative defenses for excess 

emissions during SSM events. To the contrary, the petitioners’ complaint in Essex Chemical 

Corp. was that EPA had “fail[ed] to provide that lesser standards, or no standards at all, should 

apply when the stationary source is experiencing startup, shutdown, or mechanical malfunctions 

through no fault of the manufacturer.”178 It was these variant provisions that, in the court’s 

opinion, “appear[ed] necessary” to ensure that the standards before it were reasonable.179 Again, 

the EPA believes that emission limitations in SIP provisions may include alternative emission 

limitations that can provide those “lesser standards” that apply during startup and shutdown 

events consistent with the court’s opinion but also ensure that emissions are continuously limited 

as required by the 1977 CAA Amendments defining “emission limitation.” 

As a legal matter, the court in Essex Chemical was reviewing a specific “never to be 

exceeded” standard for new and modified sources and addressed only whether the EPA’s failure 

to provide some form of flexibility during SSM events was supported by the record;180 the court 

 

177 Id. (citing International Harvester, 478 F.2d 615, 641 (D.C. Cir. 1973)). 

178 Essex Chem. Corp v. Ruckelshaus, 486 F.2d at 433 (emphasis added). 

179 See id. 

180 Id. (“the record does not support the ‘never to be exceeded’ standard currently in force”). 
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was not interpreting whether the CAA inherently required such exemptions (rather than 

alternative limits) regardless of future developments in technology. Accordingly, the D.C. 

Circuit ultimately remanded the challenged standards to the EPA for reconsideration, not 

because SSM exemptions are mandatory but rather because of comments made by the EPA 

Acting Administrator and deficiencies identified in the administrative record with respect to 

“never to be exceeded” limits for those specific standards. In short, the Essex Chemical court did 

not hold that the CAA “requires” emission limitations to include exemptions for emissions 

during SSM events as suggested by commenters. 

Furthermore, the EPA notes that the most salient legal holding of Essex Chemical with 

respect to achievability is not what the court said about the circumstances peculiar to the EPA’s 

development of those specific standards but rather is the court’s holding that standards of 

performance can be “achievable” even if there is no facility “currently in operation which can at 

all times and under all circumstances meet the standards . . . .”181 Thus, the decision supports the 

EPA’s conclusion that the CAA requires appropriately drawn emission limitations that apply on 

a continuous basis. As explained in section IV of this notice, SIP provisions also cannot include 

the affirmative defenses advocated by commenters, because those are inconsistent with CAA 

provisions concerning the jurisdiction of the courts. 

i. Comments that the EPA is requiring that all SIP emission limitations must be 

“numerical” at all times and set at the same numerical level at all times. 

Comment: Many commenters on the February 2013 proposal evidently believed that the 

EPA was proposing an interpretation of the term “emission limitation” under section 302(k) that 

 

181 Essex Chem. Corp v. Ruckelshaus, 486 F.2d 427, 433 (D.C. Cir. 1973). 
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would requires all SIP provisions to impose numerical emission limits, and that such limits must 

be set at the same numerical level at all times. These commenters argued that numerical emission 

limitations are not required by the text of section 302(k). For example, commenters pointed to 

section 302(k)’s use of “work practice or operational standard[s]” as evidence that an emission 

limitation may be composed of more than merely numerical criteria. These commenters also 

reiterated their view that section 302(k) allows for or requires alternative limits during periods of 

SSM, including non-numerical alternative limits such as work practice or operational standards. 

Response: At the outset, the EPA notes that it did not intend to imply that all emission 

limitations in SIP provisions must be expressed numerically, or that they must be set at the same 

numerical level for all modes of source operation. To the contrary, the EPA intended to indicate 

that states may elect to create emission limitations that include alternative emission limitations 

that apply during certain modes of source operation, such as startup and shutdown. This was the 

reason for inclusion of the recommended criteria for states to develop appropriate alternative 

emission limitations applicable during startup and shutdown in section VII.A of the February 

2013 proposal. The EPA has provided similar recommended criteria in this final action. The EPA 

agrees that neither section 110(a)(2)(A) nor section 302(k) inherently requires that SIP emission 

limitations must be expressed numerically. Furthermore, section 302(k) does not itself require 

imposition of numerical limitations or foreclose the use of higher numerical levels, specific 

technological controls or work practices during certain modes of operation. 

Although some CAA programs may require or impose a presumption that emission 

limitations be expressed numerically, the text of section 110(a)(2)(A) and section 302(k) does 
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not expressly state a preference for emission limitations that are in all cases numerical in form.182

Rather, as many commenters pointed out, the critical aspect of an emission limitation in general 

is that it be a “requirement . . . which limits the quantity, rate, or concentration of emissions of 

air pollutants on a continuous basis . . . .”183 Accordingly, although other regulatory requirements 

may also apply, a non-numerical design standard, equipment standard, work practice standard or 

operational standard could theoretically meet the definition of “emission limitation” for purposes 

of section 302(k) if it continuously limited the quantity, rate or concentration of air pollutants.184

By contrast, if a non-numerical requirement does not itself (or in combination with other 

components of the emission limitation) limit the quantity, rate or concentration of air pollutants 

on a continuous basis, then the non-numerical standard (or overarching requirement) does not 

meet the statutory definition of an emission limitation under section 302(k). 

Finally, the EPA does not believe that section 110(a)(2)(A) or section 302(k) mandates 

that an emission limitation be composed of a single, uniformly applicable numerical emission 

limitation. As the EPA stated in the February 2013 proposal, “[i]f sources in fact cannot meet the 

otherwise applicable emission limitations during planned events such as startup and shutdown, 

then an air agency can develop specific alternative requirements that apply during such periods, 

so long as they meet other applicable CAA requirements.”185 As explained in the EPA’s response 

in section VII.A.3 of this notice regarding the meaning of the statutory term “continuous,” the 

 

182 Numerical requirements or preferences for some emission limitations flow from substantive 

requirements of specific CAA programs, which are incorporated into section 110(a)(2)(A) by the 

requirement that SIPs “include enforceable emission limitations . . . as may be necessary or 

appropriate to meet the applicable requirements of” the CAA. CAA section 110(a)(2)(A). 

183 See, e.g., id., section 112(h)(4). 

184 For example, emission limitations must meet the requirements of various substantive 

provisions of the CAA and must be legally and practically enforceable. 

185 78 FR 12459 at 12471. 
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critical aspect for purposes of section 302(k) is not whether the emission limitation is expressed 

as a static versus variable numerical limitation but rather whether as a whole it constitutes a 

requirement that limits emissions on a continuous basis. Furthermore, any emission limitation 

must also meet all other applicable CAA requirements concerning stringency and enforceability. 

j. Comments that an emission limitation can be “continuous” even if it has different 

numerical limitations applicable during some modes of source operation or has a combination of 

numerical emission limitations and specific control technologies or work practices applicable 

during other modes of operation. 

Comment: Several commenters argued that an emission limitation can be “continuous” 

under section 302(k) even if it provides different substantive requirements applicable during 

SSM events. One commenter illustrated this position with a hypothetical: 

[W]hile Section 302 requires “emission limits” to be “continuous,” it does not 

specify . . . that the same “emission limit” must apply at all times. That is, if a 

state chooses to require sources to comply with a 40% opacity limit during 

steady-state operations, the Act does not then require the state to apply that 40% 

limit at all times, including startup, shutdown and malfunction events. 

Commenters pointed to a number of sources as justification for this position, including 

the text of section 302(k), relevant case law, legislative history of the 1977 CAA Amendments, 

prior EPA interpretations, and practical concerns. 

Response: The EPA agrees with these commenters’ conclusion that an “emission 

limitation” under section 302(k) does not need to be expressed as a static, inflexible limit on 

emissions. Rather, a SIP provision qualifying as an “emission limitation” consistent with section 

302(k) must merely limit “the quantity, rate, or concentration” of emissions, and must do so “on 

a continuous basis.” The critical aspect for purposes of section 302(k) is that the SIP provision 

impose limits on emissions on a continuous basis, regardless of whether the emission limitation 
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as a whole is expressed numerically or as a combination of numerical limitations, specific 

control technology requirements and/or work practice requirements, and regardless of whether 

the emission limitation is static or variable. For example, so long as the SIP provision meets 

other applicable requirements, it may impose different numerical limitations for startup and 

shutdown. 

The EPA also agrees that the text of section 302(k) does not require states to impose 

emission limitations that include a static, inflexible standard. Rather, the term “emission 

limitation” is merely defined as a “requirement established by the State or the Administrator 

which limits the quantity, rate, or concentration of emissions of air pollutants on a continuous 

basis . . . .” The continuous limits imposed by emission limitations are a fundamental distinction 

between emission limitations and the other control measures, means or techniques that may also 

limit emissions.186 The text of section 302(k), however, does not distinguish between a variable 

or static “requirement” that continuously limits emissions—all that is required is that the 

emissions are limited on a continuous basis. 

This interpretation is consistent with prior EPA interpretations of section 302(k), as well 

as relevant case law. In Kamp v. Hernandez, the U.S. Court of Appeals for the Ninth Circuit 

(Ninth Circuit) upheld the EPA’s interpretation of “continuous” in section 302(k), as requiring 

that “some limitation on emissions, although not necessarily the same limitation, is always 

 

186 See CAA section 110(a)(2)(A). 
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imposed” on the source.187 More recently, the D.C. Circuit favorably cited Kamp when holding 

that section 302(k) requires emission standards to limit emissions on a continuous basis and 

precludes exemptions for emissions during SSM events.188 

Legislative history confirms that Congress was primarily concerned that there be constant 

or continuous means of reducing emissions—not that the nature of those controls could not be 

different during different modes of operation.189 For example, legislative history from the 1977 

CAA Amendments states that Congress added section 302(k)’s definition of “emission 

limitation” to: 

...ma[ke] clear that constant or continuous means of reducing emissions must be 

used to meet these requirements. By the same token, intermittent or supplemental 

controls or other temporary, periodic, or limited systems of control [are] not be 

permitted as a final means of compliance.190 

 

187 Kamp v. Hernandez, 752 F.2d 1444, 1452–53 (9th Cir. 1985) (citing Chevron, U.S.A., Inc. v. 

Natural Res. Def. Council, 467 U.S. 837 (1984)) (upholding EPA’s “broader definition of 

‘continuous’” under section 302(k)). 

188 Sierra Club v. EPA, 551 F.3d 1019, 1027–28 (D.C. Cir. 2008) (quoting Kamp, 752 F.2d at 

1452). 

189 See, e.g., H.R. Rep. 95-294, at 92 (1977) (explaining that the definition of “emission 

limitation,” like the definition of “standard of performance,” was intended to “ma[ke] clear that 

constant or continuous means of reducing emissions must be used to meet th[ose] 

requirements”); S. Rep. 95-127, at 94 (explaining that the definition of “emission limitation” was 

intended to “clarify the committee’s view that the only acceptable basic strategy is one based on 

continuous emission control,” rather than “unacceptable” “[i]ntermittent controls or dispersion 

techniques . . . .”). 

190 Sierra Club v. EPA, 551 F.3d at 1027 (quoting H.R. Rep. 95-294, at 92 (1977), as reprinted in

1977 U.S.C.C.A.N. 1077, 1170); Kamp v. Hernandez, 752 F.2d at 1453–54 (same). 
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Although this legislative history demonstrates congressional intent that any “emission 

limitation” would require limits on emissions at all times, this history does not necessarily 

indicate that the emission limitation must consist of a single static numerical limitation. 

Accordingly, this legislative history is consistent with the EPA’s view that section 302(k) 

requires continuous limits on emissions and that variable (albeit still continuous) limits on 

emissions can qualify as an emission limitation for purposes of section 302(k). 

Finally, although the EPA agrees with these commenters’ conclusion, the EPA does not 

agree with these commenters’ view that practical concerns require states in all cases to establish 

alternative emission limitations for modes of operation such as startup and shutdown within any 

continuously applicable emission limitation. Principles of cooperative federalism incorporated 

into section 110 allow states great leeway in developing SIP emission limitations, provided those 

limitations comply with applicable legal requirements.191 States are thus not required to establish 

alternative emission limitations for any sources during startup and shutdown, but they may elect 

to do so. Neither the definition of “emission limitation” in section 302(k) nor the requirements of 

section 110(a)(2)(A) explicitly require states to develop emission limitations that include 

alternative emission limitations for periods of SSM, just as they do not explicitly preclude states 

from doing so. 

k. Comments that an emission limitation can be “continuous” even if it includes 

periods of exemptions from the emission limitation. 

 

191 As discussed above and elsewhere in this notice, those requirements include satisfying the 

definition of “emission limitation” under CAA section 302(k), and being “enforceable” in 

accordance with section 110(a)(2)(A). 
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Comment: Commenters asserted that a requirement limiting emissions can be 

“continuous” even if a SIP provision includes periods of exemption from that limit. For example, 

some commenters contended that SSM exemptions only excuse compliance with emission 

limitations for a “short duration,” or “brief” period of time, and that these purportedly ephemeral 

interruptions should not be viewed as rendering the requirement noncontinuous. Other 

commenters contended that the EPA misinterpreted portions of the D.C. Circuit’s opinion in 

Sierra Club v. EPA,

192 interpreting section 302(k). Specifically, this group of commenters 

claimed that because the holding of that case was based on a combined reading of sections 112 

and 302(k), the court’s interpretation of the word “continuous” in section 302(k) does not extend 

outside the context of section 112. This included one commenter who hypothesized, in a onesentence footnote, that “[i]n the cooperative-federalism context”—presumably of section 110—

“the standard of flexibility that Congress gave the States with respect to selecting the elements of 

their SIPs is not necessarily the same standard Congress set to govern EPA’s responsibility to 

establish the NAAQS or section 112 standards.” Still other commenters further argued that the 

EPA mischaracterized legislative history discussing “continuous” in section 302(k). According 

to these commenters, the context of legislative history on section 302(k) indicates that Congress 

did not intend for the word “continuous” to be given its plain meaning but rather intended to use 

“continuous” in relation only to specific types of intermittent controls. 

 

192 551 F.3d 1019 (D.C. Cir. 2008). 
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Response: The EPA disagrees with these commenters. First, commenters’ interpretation 

would contravene the plain meaning of “continuous.” Section 302(k) defines “emission 

limitation” as a requirement that “limits the quantity, rate, or concentration of emissions of air 

pollutants on a continuous basis . . . .”193 Although the word “continuous” is not separately 

defined in the Act, its plain and unambiguous meaning is “uninterrupted.”194 Accordingly, to the 

extent that a SIP provision provides for any period of time when a source is not subject to any 

requirement that limits emissions, the requirements limiting the source’s emissions by definition 

cannot do so “on a continuous basis.” Such a source would not be subject to an “emission 

limitation,” as that term is defined under section 302(k). The same principle applies even for 

“brief” exemptions from limits on emissions, because such exemptions nevertheless render the 

emission limitation noncontinuous. 

Second, the EPA disagrees with commenters’ interpretation of the D.C. Circuit’s opinion 

in Sierra Club. While the court’s ultimate decision was based on “sections 112 and 302(k) . . . 

read together,”195 the court’s analysis of what makes a standard “continuous” was based on 

section 302(k) alone.196 Although the precise components of an emission limitation or standard 

 

193 CAA section 302(k). 

194 See Webster’s Third New International Dictionary 493–94 (Phillip Babcock Gove ed., 

Merriam-Webster 1993) (defining “continuous”). 

195 Sierra Club, 551 F.3d at 1027. 

196 See id. (quoting H.R. Rep. 95–294, at 92 (1977), as reprinted in 1977 U.S.C.C.A.N. 1077, 

1170); see also Kamp v. Hernandez, 752 F.2d at 1453–54 (quoting the same and coming to the 

same conclusion). 
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may expand depending on which other provisions of the CAA are applicable, the bedrock 

definition for what it means to be an “emission limitation” under section 302(k) does not. 

Congress appeared to share the EPA’s view that section 302(k) provides a bedrock definition of 

“emission limitation” applicable “to all emission limitations under the act, not just to limitations 

under sections 110, 111, or 112 of the act.”197 Accordingly, the D.C. Circuit’s interpretation of 

section 302(k) applies equally in the context of SIP provisions developed by states as in the 

context of MACT standards developed by the EPA, even if additional requirements may be 

different.198 

Finally, the EPA rejects commenters’ contention that section 302(k)’s legislative history 

indicates that use of the word “continuous” in the definition of “emission limitation” was merely 

intended to prevent the use of intermittent controls or, even more narrowly, only dispersion 

techniques. While legislative history of the 1977 Amendments discusses at length the concerns 

associated with these types of controls, section 302(k) was not intended to merely prevent the 

narrow problem of intermittent controls. To the contrary, the House Report states that under 

 

197 See H.R. 95-294, at 92 (1977); see also section 302 (stating that the definitions appearing 

therein apply “[w]hen used in this chapter”). 

198 The fact that CAA section 110 incorporates principles of cooperative federalism does not 

inevitably mean that the definition of “emission limitation” under section 302(k) changes 

depending on whether it is applied in the context of section 110 versus section 112. Accordingly, 

in the context of judicial interpretation of a statute, the U.S. Supreme Court has held that judges 

cannot “give the same statutory text different meanings in different cases.” Clark v. Martinez, 

543 U.S. 371, 386 (2005). The EPA believes that the text and legislative history of section 

302(k) evince congressional intent to consistently apply the definition of “emission limitation” 

under section 302(k) rather than to develop an inconsistent interpretation peculiar to section 110. 
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section 302(k)’s definition of emission limitation, “intermittent or supplemental controls or other 

temporary, periodic, or limited systems of control would not be permitted as a final means of 

compliance.”199 

In explaining congressional intent behind adopting a statutory definition of “emission 

limitation,” the House Report articulated a rationale broader than would apply if Congress had 

merely intended to prohibit the tall stacks and dispersion techniques that commenters claim were 

targeted: “Each source’s prescribed emission limitation is the fundamental tool for assuring that 

ambient standards are attained and maintained. Without an enforceable emission limitation 

which will be complied with at all times, there can be no assurance that ambient standards will be 

attained and maintained.”200 By contrast, Congress criticized limitations structured in ways that 

could not “provide assurances that the emission limitation will be met at all times,” or that would 

sometimes allow the “emission limitation [to] be exceeded, perhaps by a wide margin . . . .”201

Such flaws “would defeat the remedy provision provided by section 304 of the act which allows 

 

199 H.R. 95-294, at 92 (emphasis added). 

200 Id. (emphasis added). The Senate Report expressed a similar sentiment. See S. Rep. No. 95-

127, at 94–95 (1977) (explaining that the definition of “emission limitation” was intended “to 

clarify the committee’s view that the only acceptable basic strategy [for emission limitations in 

SIPs] is one based on continuous emission control”). 

201 See H.R. 95-294, at 92. 
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citizens to assure compliance with emission limitations and other requirements of the act.”202

Exemptions for emissions during SSM events have the same effects.203 

In adopting section 302(k)’s definition of “emission limitation,” Congress did not merely 

intend to prohibit the use of intermittent controls as final compliance strategies—much less 

intermittent controls as narrowly defined by commenters to mean only dispersion techniques and 

certain “tall stacks.” Rather, Congress intended to eliminate the fundamental problems that were 

illustrated by use of those controls.204 SSM exemptions and affirmative defenses raise many of 

the same problems, and addressing those problems through this action fully accords with section 

302(k)’s legislative history. 

l. Comments that the “as may be necessary or appropriate” language in section 

110(a)(2)(A) per se authorizes states to create exemptions in SIP emission limitations. 

Comment: Some commenters contended that section 110(a)(2)(A) merely requires states 

to include emission limitations and other control measures in their SIPs “as may be necessary or 

appropriate.” These commenters interpreted that language as a broad delegation of discretion to 

states, to develop SIP provisions that are necessary or appropriate to satisfy the particular needs 

 

202 See id. 

203 See, e.g., NRDC v. EPA, 749 F.3d 1055, 1064 (D.C. Cir. 2014) (holding that an affirmative 

defense for excess emissions during malfunctions contradicts the requirement that an emission 

limitation be “continuous”). 

204 See, e.g., H.R. 95-294, at 94 (noting that the provision was intended to overcome “objections” 

to such measures, not merely the measures themselves); id. at 92 (indicating that the problems 

arise from “temporary, periodic, or limited systems of control” generally, not merely dispersion 

techniques or tall stacks). 
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of a state, as judged solely by that state. Some of the commenters argued that the EPA’s 

interpretation of “as may be necessary or appropriate” would, in all circumstances, improperly 

substitute the EPA’s judgment for that of the state concerning what emission limitations are 

necessary or appropriate. One commenter highlighted the EPA’s proposal to deny the Petition 

with respect to a specific SIP provision of the South Carolina SIP that entirely exempts a source 

category from regulation.205 According to this commenter, if the “as may be necessary or 

appropriate” language grants states the authority to exempt a source category from regulation 

entirely, then it must allow states to exempt sources selectively during SSM events. 

Some commenters further argued that regardless of what the terms “emission limitations” 

or “other control measures, means, or techniques” mean, section 110(a)(2)(A) only requires 

states to include such emission controls in SIPs “as may be necessary or appropriate” to meet the 

NAAQS, or some requirement germane to attainment of the NAAQS, such as various 

technology-based standards or general principles of enforceability. Commenters also disagreed 

with the EPA’s purported interpretation that the statutory phrase “as may be necessary” only 

qualifies what “other control[s]” are required, rather than also qualifying what emission 

limitations are required. According to these commenters, that interpretation is a vestige of the 

1970 CAA and was foreclosed by textual changes in the 1977 CAA Amendments or, 

alternatively, the 1990 CAA Amendments. 

Response: The EPA disagrees with the commenters’ interpretation of the “as may be 

necessary or appropriate” language of section 110(a)(2)(A). As an initial matter, those 

commenters contending that section 110(a)(2)(A) is only concerned with what is “necessary or 

 

205 See 78 FR 12459 at 12512 (citing S.C. Code Ann. Regs. 61–62.5 St 5.2(I)(b)(14)). 
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appropriate” to attain and maintain the NAAQS (or some requirement germane to the NAAQS) 

ignore the plain language of section 110(a)(2)(A). While the predecessor provisions to section 

110(a)(2)(A) prior to the 1990 CAA Amendments did indeed speak in terms of emissions 

controls “necessary to insure attainment and maintenance of [the NAAQS],”206 the statute in 

effect today requires controls “necessary or appropriate to meet the applicable requirements of 

this chapter,”207—i.e., to meet the requirements of the CAA as a whole. Thus, at a minimum, the 

EPA interprets the phrase “as may be necessary or appropriate” to include what is necessary or 

appropriate to meet legal requirements of the CAA, including the requirement that emission 

limitations must apply on a continuous basis. 

Regardless of whether all SIPs must always contain emission limitations, the text of the 

CAA is clear that the EPA is at a minimum tasked with determining whether SIPs include all 

emission limitations that are “necessary” (i.e., required) “to meet the applicable requirements of” 

that CAA. Broadly speaking, this requires that the EPA determine whether the SIP meets the 

basic legal requirements applicable to all SIPs (e.g., the requirements of section 110(a)(2)(A) 

through (M)), whether the SIP contains emission limitations necessary to meet substantive 

requirements of the Act (e.g., RACT-level controls in nonattainment areas) and whether all 

emission limitations and other controls, as well as the schedules and timetables for compliance, 

are legally and functionally enforceable. 

In every state subject to this SIP call, the EPA has previously concluded in approving the 

existing SIP provisions that the emission limitations are necessary to comply with legal 

 

206 See, e.g., Clean Air Act of 1970, Pub. L. 91-604, § 4(a), 84 Stat. 1676, 1680 (December 31, 

1970). 

207 Section 110(a)(2)(A). 
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requirements of the CAA. The states in question would not have developed and submitted them, 

and the EPA would not have approved them, unless the state and the EPA considered those 

emission limitations fulfilled a CAA requirement in the first instance. However, the automatic 

and discretionary exemptions for emissions during SSM events in the SIP provisions at issue in 

this action render those necessary emission limitations noncontinuous, and thus not meeting the 

statutory definition of “emission limitations” as defined in section 302(k). Accordingly, 

regardless of whether all SIPs must always include emission limitations, these specific SIP 

provisions fail to meet a fundamental requirement of the CAA because they do not impose the 

continuous emission limitations required by the Act. 

The EPA also disagrees with the argument raised by commenters that its denial of the 

Petition with respect to a South Carolina SIP provision supports the validity of SSM exemptions 

in SIP emission limitations.208 In that situation, the state determined that regulating the source 

category at issue was not a necessary or appropriate means of meeting the requirements of the 

CAA. The EPA’s approval of that provision indicates that the Agency agreed with that 

determination. This factual scenario is not the same as one in which the state has determined that 

regulation of the source category is necessary or appropriate to meet CAA requirements. Once 

the determination is made that the source category must or should be regulated, then the SIP 

provisions developed by the state to regulate the source must meet applicable requirements. 

These include that any limits on emissions must be consistent with CAA requirements, including 

the requirement that any emission limitation limit emissions on a continuous basis. The EPA 

agrees that a state can validly determine that regulation of a source category is not necessary, so 

 

208 See 78 FR 12459 at 12512 (citing S.C. Code Ann. Regs. 61–62.5 St 5.2(I)(b)(14)). 
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long as this is consistent with CAA requirements. This is not the same as allowing impermissible 

exemptions for emissions from a source category that must be regulated. 

Finally, the EPA does not agree with commenters’ allegations that that the EPA’s 

interpretation of section 110(a)(2)(A) eliminates the states’ discretion to take local concerns into 

account when developing their SIP provisions. Rather, for reasons discussed in more detail in the 

EPA’s response in section V.D.2 of this document regarding cooperative federalism, the EPA’s 

interpretation is fully consistent with the principles of cooperative federalism codified in the 

CAA. As courts have concluded, although Congress provided states with “considerable latitude 

in fashioning SIPs, the CAA ‘nonetheless subjects the States to strict minimum compliance 

requirements’ and gives EPA the authority to determine a state’s compliance with the 

requirements.”209 This interpretation is also consistent with congressional intent that the EPA 

exercise supervisory responsibility to ensure that, inter alia, SIPs satisfy the broad requirements 

that section 110(a)(2) mandates that SIPs “shall” satisfy.210 Where the EPA determines that a SIP 

provision does not satisfy legal requirements, the EPA is not substituting its judgment for that of 

the state but rather is determining whether the state’s judgment falls within the wide boundaries 

of the CAA. 

m. Comments that a “general duty” provision—or comparable generic provisions 

that require sources to “exercise good engineering judgment,” to “minimize emissions” or to “not 

 

209 Michigan v. EPA, 213 F.3d 663, 687 (D.C. Cir. 2000) (quoting Union Elec. Co. v. EPA, 427 

U.S. 246, 256–57 (1976)). 

210 With respect to section 110(a)(2)(A), this means that a SIP must at least contain legitimate, 

enforceable emission limitations to the extent they are necessary or appropriate “to meet the 

applicable requirements” of the Act. Likewise, SIPs cannot have enforcement discretion 

provisions or affirmative defense provisions that contravene the fundamental requirements 

concerning the enforcement of SIP provisions. 
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cause a violation of the NAAQS”—inoculate or make up for exemptions in specific emission 

limitations that apply to the source. 

Comment: Numerous commenters argued that even if some of the SIP provisions with 

SSM exemptions identified in this SIP call are not themselves emission limitations, they are 

nevertheless components of valid emission limitations. According to these commenters, some 

SIPs contain separate “general duty” provisions that are not affected by SSM exemptions and 

thus have the effect of limiting emissions from sources during SSM events that are explicitly 

exempted from the emission limitations in the SIP. These general-duty provisions vary, but most 

of them: (1) instruct sources to “minimize emissions” consistent with good air pollution control 

practices, (2) prohibit sources from emitting pollutants that cause a violation of the NAAQS, or 

(3) prohibit source operators from “improperly operating or maintaining” their facilities. 

Commenters contended that these general-duty provisions are requirements that—either 

alone or in combination with other requirements—have the effect of limiting emissions on a 

continuous basis. In other words, the commenter asserted that these general-duty provisions 

impose limits on emissions during SSM events, when the otherwise applicable controls no longer 

apply. According to these commenters, SSM exemptions that excuse noncompliance with typical 

controls do not interrupt the continuous application of an “emission limitation,” because these 

general-duty provisions elsewhere in the SIP or in a separate permit are part of the emission 

limitation and apply even during SSM events. 

Some commenters further argued that some SSM exemptions themselves demonstrate 

that sources remain subject to general-duty provisions during SSM events. These SSM 

exemptions require sources seeking to qualify for the exemption to demonstrate that, inter alia, 

they were at the time complying with certain general duties. Accordingly, these commenters 
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contended that the SSM exemption itself demonstrates that sources remain subject to 

requirements that limit their emissions during SSM events, even when the source is excused 

from complying with other components of the overarching emission limitation. 

Finally, as evidence that these general-duty clauses must be permissible under the CAA, 

some commenters pointed to similar federal requirements established by the EPA under the 

NSPS and NESHAP programs.211 These commenters argued that the D.C. Circuit’s decision in 

Sierra Club v. Johnson212 was limited to circumstances unique to section 112 and does not 

support a per se prohibition on general-duty clauses operating as “emission limitations.” 

Response: The EPA disagrees with these comments. As described elsewhere in this 

response to comments, all “emission limitations” must limit emissions of air pollutants on a 

continuous basis.213 The specific requirements of a SIP emission limitation must be discernible 

on the face of the provision, must meet the applicable substantive and stringency requirements of 

the CAA and must be legally and practically enforceable. The general-duty clauses identified by 

these commenters are not part of the putative emission limitations contained in these SIP 

provisions. To the contrary, these general-duty clauses are often located in different parts of the 

SIP and are often not cross-referenced or otherwise identified as part of the putative continuously 

applicable emission limitation. 

Furthermore, the fact that a SIP provision includes prerequisites to qualifying for an SSM 

exemption does not mean those prerequisites are themselves an “alternative emission limitation” 

applicable during SSM events. The text and context of the SIP provisions at issue in this SIP call 

 

211 See, e.g., 40 CFR 63.6(e)(3). 

212 551 F.3d 1019, 1027–28 (D.C. Cir. 2008). 

213 CAA section 302(k). 
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action make clear that the conditions under which sources qualify for an SSM exemption are not 

themselves components of an overarching emission limitation—i.e., a requirement that limits 

emissions of air pollutants from the affected source on a continuous basis. Rather, these 

provisions merely identify the circumstances when sources are exempt from emission 

limitations. 

Reviewing an example of the SIP provisions cited by commenters is illustrative of this 

point. For example, several commenters pointed to provisions in Alabama’s SIP that excuse a 

source from complying with an otherwise applicable emission limitation only when the permittee 

“took all reasonable steps to minimize emissions” and the “permitted facility was at the time 

being properly operated.” According to commenters, the general duties in this provision—to take 

reasonable steps to minimize emissions, and to properly operate the facility—ensure that even 

during SSM events, the permittee remains subject to requirements limiting emissions. 

However, a review of the provisions themselves in context—not selectively quoted—

reveals that these general-duty provisions were included in the SIP not as components of an 

emission limitation but rather as components of an exception to that emission limitation. In order 

to qualify, the SIP requires the permittee to have taken “all reasonable steps to minimize levels 

of emissions that exceeded the emission standard”214—an acknowledgement that the emissions 

to be “minimize[d]” are those that “exceed[]” (i.e., go beyond) the required limits of “the 

 

214 Ala. Admin. Code Rule 335-3-14-.03(h)(2)(ii)(III) (emphasis added). 
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emission standard.” In case there were any doubt that the general-duty provisions identified are 

elements of an exemption from an emission limitation, rather than components of the emission 

limitation itself, the provisions apply during what the Alabama SIP calls “[e]xceedances of

emission limitations”215 and are found within a broader section addressing “Exceptions to 

violations of emission limitations.”216 By exempting sources from compliance with “the emission 

standard,” these SSM exemptions render the SIP emission limitation noncontinuous, contrary to 

section 302(k).217 

The consequences for failing to satisfy the preconditions for an exemption further bolster 

the conclusion that these preconditions are not themselves part of an emission limitation. Failure 

to meet the “general duty” preconditions for an SSM exemption means that the source remains 

subject to the otherwise applicable emission limitation during the SSM event and is thus liable 

for violating the emission limitation. If those general duties were independent parts of an 

emission limitation (rather than merely preconditions for an exemption), then one would expect 

that periods of time could exist when the source was liable for violating those general duties 

rather than the default emission limitation. 

The general-duty provisions that apply as part of the SSM exemption are not alternative 

emission limitations; they merely define an unlawful exemption to an emission limitation. States 

have discretion to fix this issue in a number of ways, including by removing the exceptions 

entirely, by replacing these exceptions with alternative emission limitations including specific 

 

215 Id. at 335-3-14-.03(h)(2)(ii) (emphasis added). 

216 Id. at 335-3-14-.03(h) (emphasis added). 

217 See CAA section 302(k) (defining “emission limitation” and “emission standard”). 
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control technologies or work practices that do ensure continuous limits on emissions or by 

reformulating the entire emission limitation. 

In addition to the EPA’s fundamental disagreement with commenters that these generalduty provisions are actually components of emission limitations, the EPA has additional 

concerns about whether many of these provisions could operate as stand-alone emission 

limitations even if they were properly identified as portions of the overall emissions limitations 

in the SIP.218 Furthermore, some of these general-duty provisions do not meet the level of 

stringency required to be an “emission limitation” compliant with specific substantive provisions 

of the CAA applicable to SIP provisions.219 Accordingly, while states are free to include generalduty provisions in their SIPs as separate additional requirements, for example, to ensure that 

owners and operators act consistent with reasonable standards of care, the EPA does not 

recommend using these background standards to bridge unlawful interruptions in an emission 

limitation.220 

The NSPS and NESHAP emission standards and limitations that the EPA has issued 

since Sierra Club demonstrate the distinct roles played by emission limitations and general-duty 

provisions. The emission limitations themselves are clear and legally and functionally 

enforceable, and they are composed of obviously integrated requirements that limit emissions on 

 

218 See Sierra Club, 551 F.3d at 1026 (discussing the EPA’s prior determinations that 

“compliance with the general duty on its own was insufficient to prevent the SSM exemption 

from becoming a ‘blanket’ exemption”). 

219 See, e.g., Sierra Club v. EPA, 551 F.3d at 1027–28 (so holding with respect to section 112). 

220 For example, the EPA has concerns the some of these general-duty provisions, if at any point 

relied upon as the sole requirement purportedly limiting emissions, could undermine the ability 

to ensure compliance with SIP emission limitations relied on to achieve the NAAQS and other 

relevant CAA requirements at all times. See section 110(a)(2)(A), (C); US Magnesium, LLC v. 

EPA, 690 F.3d 1157, 1161–62 (10th Cir. 2012). 
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a continuous basis during all modes of source operation. Crucially, the general-duty provisions in 

these post-Sierra Club regulations merely supplement the integrated emission limitation; they do 

not supplant the emission limitation, which independently requires continuous limits on 

emissions. As discussed elsewhere in this document, the fact that the EPA is in the process of 

updating its own regulations to comply with CAA requirements does not alter the legal 

requirements applicable to SIPs. 

n. Comments that EPA’s action on the petition is a “change of policy.” 

Comment: A number of commenters claimed that the EPA’s action on the Petition is 

illegitimate because it is based upon a “change of policy.” Some commenters claimed that the 

EPA’s reliance on the definition of “emission limitation” in section 302(k) and the requirements 

for SIP provisions in section 110(a)(2) as barring automatic exemptions are “new.” These 

commenters claimed that the EPA has historically relied on the fact that NAAQS are ambientstandard-based and that the EPA has relied also on the fact that SSM exemptions had potential 

adverse air quality impacts as the basis for interpreting the CAA to preclude exemptions. The 

commenters argued that this basis for the SSM Policy is evidenced by the fact that EPA itself 

historically included SSM exemptions in NSPS and NESHAP rules, which establish emission 

limitations that should be governed by section 302(k) as well. 

Other commenters claimed that the EPA is changing its SSM Policy by seeking to revoke 

“enforcement discretion” exercised on the part of states, which the EPA specifically recognized 

as an acceptable approach in the 1983 SSM Guidance. A commenter asserted that “fairness 

principles” mean that the EPA cannot require a state to modify its SIP without substantial 

justification. The commenter further contended that the EPA’s claim that it has a longstanding 

interpretation of the CAA that automatic exemptions are not allowed in SIP provisions is false; 
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otherwise, the commenter argued, the EPA would not have approved some of the provisions at 

issue in the SIP call long after 1982. As evidence for this argument, the commenter pointed to 

the West Virginia regulations that provide an automatic exemption. 

Finally, other commenters argued that the EPA’s changed interpretation of the CAA 

requires an acknowledgement that the SSM Policy is being changed and a rational explanation 

for such change. These commenters noted that the EPA previously argued in a brief for the type 

of exemption provisions that it is now claiming are deficient, citing Sierra Club v. EPA, No. 02-

1135 (D.C. Cir. March 14, 2008). The commenters claimed that the EPA has provided no 

rational basis for its change in interpretation of the CAA concerning exemptions for emissions 

during SSM events. 

Response: The EPA’s longstanding position, at least since issuance of the 1982 SSM 

Guidance, is that SIP provisions providing an exemption from emission limitations for emissions 

during SSM events are prohibited by the CAA. The EPA’s guidance documents issued in 1982 

and 1983 expressly recognized that in place of exemptions, states should exercise enforcement 

discretion in determining whether to pursue a violation of an emission limitation. In the 1983 

SSM Guidance, the EPA made recommendations for states that elected to adopt specific SIP 

provisions affecting their own exercise of enforcement discretion, so long as those provisions do 

not apply to enforcement discretion of the EPA or other parties under the citizen suit provision of 

the CAA. More than 15 years ago, in the 1999 SSM Guidance, the EPA reiterated its 

longstanding position that it is inappropriate for SIPs to exempt SSM emissions from compliance 

with emission limitations and repeated that instead of incorporating exemptions, enforcement 

discretion could be an appropriate tool. In addition, EPA clarified at that time that a narrowly 

tailored affirmative defense might also be an appropriate tool for addressing excess emissions in 
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a SIP provision. However, in response to recent court decisions, and as discussed in detail in 

section IV of this document, the EPA no longer interprets the CAA to permit affirmative defense 

provisions in SIPs. 

Although the EPA did not expressly rely on the definition of “emission limitation” in 

section 302(k) as the basis for its SSM Policy in each of these guidance documents, it did rely on 

the purpose of the NAAQS program and the underlying statutory provisions (including section 

110) governing that program. In the 1999 SSM Guidance, however, the EPA indicated that the 

definition of emission limitation in section 302(k) was part of the basis for its position 

concerning SIP provisions.221 After the EPA issued the 1999 SSM Guidance, the D.C. Circuit 

issued a decision holding that the definition of emission limitation in section 302(k) does not 

allow for periods when sources are not subject to emissions standards.222 While the court’s 

decision concerned the section 112 program addressing hazardous air pollutants, the EPA 

believes that the court’s ruling concerning section 302(k) applies equally in the context of SIP 

provisions because the definition of emission limitation also applies to SIP requirements. That 

court’s decision is consistent with and provides support for the EPA’s longstanding position in 

the SSM Policy that exemptions from compliance with SIP emission limitations are not 

appropriate under the CAA. 

Commenters claimed that by interpreting the CAA to prohibit exemptions for emissions 

during SSM events the EPA is revoking “enforcement discretion” exercised by the state. This is 

simply not true. As part of state programs governing enforcement, states can include regulatory 

 

221 See 1999 SSM Guidance at 2, footnote 1. The EPA included section 302(k) among the 

statutory provisions that formed the basis for its interpretations of the CAA in that document. 

222 Sierra Club, 551 F.3d 1019 (D.C. Cir. 2008). 
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provisions or may adopt policies setting forth criteria for how they plan to exercise their own 

enforcement authority. Under section 110(a)(2), states must have adequate authority to enforce 

provisions adopted into the SIP, but states can establish criteria for how they plan to exercise that 

authority. Such enforcement discretion provisions cannot, however, impinge upon the 

enforcement authority of the EPA or of others pursuant to the citizen suit provision of the CAA. 

The EPA notes that the requirement for adequate enforcement authority to enforce CAA 

requirements is likewise a bar to automatic exemptions from compliance during SSM events. 

Commenters confused the EPA’s evolution in describing the basis for its longstanding 

SSM Policy as a change in the SSM Policy itself. The EPA’s interpretation of the CAA in the 

SSM Policy has not changed with respect to exemptions for emissions during SSM events. The 

EPA’s discussion of the basis for its longstanding interpretation has evolved and become more 

robust over time as the EPA has responded to comments in rulemakings and in response to court 

decisions. In support of its interpretation of the CAA that exemptions for periods of SSM are not 

acceptable in SIPs, the EPA has long relied on its view that NAAQS are health-based standards 

and that exemptions undermine the ability of SIPs to attain and maintain the NAAQS, to protect 

PSD increments, to improve visibility and to meet other CAA requirements. By contrast, the 

EPA historically took the position that SSM exemptions were acceptable for certain technologybased standards, such as NSPS and NESHAP standards, and argued that position in the Sierra 

Club case cited by commenters. However, in that case, the court explicitly ruled against the 

EPA’s interpretation, holding that exemptions for emissions during SSM events are precluded by 

the definition of “emission limitation” in CAA section 302(k). The Sierra Club court’s rationale 

thus provided additional support for the EPA’s longstanding position with respect to SSM 

exemptions in SIP provisions, and in more recent actions the EPA has relied on the reasoning 
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from the court’s decision as further support for its current SSM Policy. Thus, even if the EPA 

were proceeding under a “change of policy” here as the commenters claimed, the EPA has 

adequately explained the basis for its current SSM Policy, including the basis for any actual 

“change” in that guidance (e.g., the actual change in the SSM Policy with respect to affirmative 

defense provisions in SIPs). Courts have upheld an agency’s authority to revise its interpretation 

of a statute, so long as that change of interpretation is explained.223 

o. Comments that the EPA’s proposed action on the petition is based on a “changed 

interpretation” of the definition of “emission limitation.” 

Comment: Commenters claimed that the EPA’s action on the Petition is based on a 

changed interpretation of the term “emission limitation” and that the Agency cannot apply that 

changed interpretation “retroactively.” One commenter cited several cases for the proposition 

that retroactivity is disfavored and that the EPA is applying this new interpretation retroactively 

to existing SIP provisions. The commenter claimed that the EPA approved the existing SIP 

provisions with full knowledge of what those provisions were and “consistent with the 

provisions EPA itself adopted and courts required.” The commenter characterized the SIP 

provisions for which the EPA is issuing a SIP call as “enforcement discretion” provisions and 

“affirmative defense” provisions for startup and shutdown. The commenter contended that the 

EPA does not have authority to issue a SIP call on the premise that the CAA is less flexible than 

the Agency previously thought. The commenter concluded that “[t]he factors of repose, 

reasonable reliance, and settled expectations favor not imposing EPA’s new interpretations.” 

 

223 The EPA emphasized this important point in the SNPR. See 79 FR 55919 at 55931. 
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Response: The EPA disagrees that this SIP call action has “retroactive” effect. As 

recognized by the commenter, this SIP call action does not automatically change the terms of the 

existing SIP or of any existing SIP provision, nor does it mean that affected sources could be 

held liable in an enforcement case for past emissions that occurred when the deficient SIP 

provisions still applied. Rather, the EPA is exercising its clear statutory authority to call for the 

affected states to revise specific deficient SIP provisions so that the SIP provisions will comply 

with the requirements of the CAA prospectively and so that affected sources will be required to 

comply with the revised SIP provisions prospectively. 

To the extent that a SIP provision complied with previous EPA interpretations of the 

CAA that the Agency has since determined are flawed, or to the extent that the EPA erroneously 

approved a SIP provision that was inconsistent with the terms of the CAA, the EPA disagrees 

that it is precluded from requiring the state to modify its SIP now so that it is consistent with the 

Act. In fact, that is precisely the type of situation that the SIP call provision of the CAA is 

designed to address. Specifically, section 110(k)(5) begins, “[w]henever” the EPA determines 

that an applicable implementation plan is inadequate to attain or maintain the NAAQS, to 

mitigate adequately interstate pollutant transport, or “to otherwise comply with any requirement” 

of the Act, the EPA must call for the SIP to be revised. The commenter does not question that 

sections 110(a)(2) and 302(k) are requirements of the Act. Thus, the EPA has authority under 

section 110(k)(5) to call on states to revise their SIP provisions to be consistent with those 

requirements. 

The EPA disagrees that the doctrines of “repose,” “reasonable reliance” and “settled 

expectations” preclude such an action. The CAA is clear that “whenever” the EPA determines 

that a SIP provision is inconsistent with the statute, “the Administrator shall” notify the state of 
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the inadequacies and establish a schedule for correction. This language does not provide the 

Agency with discretion to consider the factors cited by the commenter in deciding whether to 

call for a SIP revision once it is determined to be flawed. Here, the EPA has determined that the 

SIP provisions at issue are flawed and thus the Agency was required to notify the states to 

correct the inadequacies. 

p. Comments that the EPA should not encourage states to rely on enforcement 

discretion because this will inevitably lead to states’ creating emission limitations that some 

sources cannot meet. 

Comment: Commenters claimed that it is not appropriate for the EPA to encourage states 

to exercise enforcement discretion rather than to encourage them either to define periods when 

numerical emission limitations do not apply or to develop alternative emission limitations or 

other control measures. The commenters contended that inclusion of an enforcement discretion 

provision in a SIP is superfluous. The commenter cited to Portland Cement, where the D.C. 

Circuit court stated that “an excessively broad theory of enforcement discretion might endanger 

securing compliance with promulgated standards.”224 The commenter also cited the Marathon 

Oil case in the Ninth Circuit in which the court rejected an approach that relied heavily on 

enforcement discretion. The commenter then asserted that sources are liable for violations and 

that “[s]ources should not be required to litigate remedy for violations they cannot avoid.”225 The 

commenter concluded that it is “unreasonable for EPA to subject itself to claims that it must 

exercise its federal enforcement authority in the event a state refuses to enforce unachievable 

standards, or for states to put source owners and operators in jeopardy of criminal prosecution for 

 

224 486 F.2d at 399 n.91. 

225 Marathon Oil Co. v. Environmental Protection Agency, 564 F.2d 1253 (9th Cir. 1977). 
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starting up a source with knowledge that a numerical emission limitation might be exceeded. In 

summary, the commenter appeared to argue that the EPA should require states to establish 

alternative numerical emission limitations or other control requirements during SSM events, 

rather than merely eliminating SSM exemptions and relying on enforcement discretion to address 

SSM emissions. 

Response: The EPA disagrees with the commenter’s suggestion that the EPA should 

discourage states from relying on enforcement discretion. Enforcement discretion is a valid state 

prerogative, long recognized by courts. However, the EPA agrees with the commenter that states 

should not adopt overly broad enforcement discretion provisions for inclusion in their SIPs. 

Section 110(a)(2) requires states to have adequate enforcement authority, and overly broad 

enforcement discretion provisions would run afoul of this requirement if they have the effect of 

precluding adequate state authority to enforce SIP requirements. The EPA also agrees that states 

may elect to include alternative emission limitations, whether expressed numerically or 

otherwise, for certain periods of normal operations, including startup and shutdown. 

It is unclear precisely what the commenters are advocating when they suggest that 

sources should not be subject to litigating a remedy for violations they cannot avoid. The likely 

interpretation is that the commenters believe that excess emissions during unavoidable events 

should be automatically exempted (i.e., not considered a violation). This approach was rejected 

by the court in Sierra Club v. Johnson, because it was not consistent with the definition of 

emission limitation in section 302(k). As previously explained in the February 2013 proposal and 

in this notice, the EPA believes that definition, and thus the court’s holding in Sierra Club, is 

equally relevant for the SIP program. 
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With respect to a commenter’s concerns about criminal enforcement, the EPA disagrees 

that sources will be unable to start operations because they will automatically be subject to 

criminal prosecution if an emission limitation is exceeded during a malfunction. Under CAA 

section 113(c), criminal enforcement for violation of a SIP can occur when a person knowingly 

violates a requirement or prohibition of an implementation plan “during any period of federally 

assumed enforcement or more than 30 days after having been notified” under the provisions 

governing notification that the person is violating that specific requirement of the SIP. The EPA 

is unaware of any jurisdictions where federally assumed enforcement is in force, and the EPA 

does not anticipate that this situation would arise often. Thus, in almost every case, criminal 

enforcement would not occur in the absence of a pending notification of a civil enforcement case 

and could then apply only for repeated violation of the activity at issue in that civil action. 

Moreover, the concern raised by the commenter is one that would exist if there is any 

requirement that applies during a period of malfunction beyond the owner’s control. The 

commenter’s preferred way to address this concern would be to exempt these periods from 

compliance with any requirements, an approach rejected by the Sierra Club court as inconsistent 

with the definition of “emission limitation” and an approach that the EPA’s longstanding SSM 

Policy has explained is inconsistent with the purpose of the NAAQS program, which is to ensure 

public health is protected through attainment and maintenance of the NAAQS, protection of PSD 

increments, improvement of visibility and compliance with other requirements of the CAA. 

Finally, to the extent that the commenter was advocating that the EPA should require 

states to develop SIP provisions that impose alternative emission limitations during certain 

modes of source operation such as startup and shutdown to replace SSM exemptions, the EPA 

notes that to require states to do so would not be consistent with the principles of cooperative 
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federalism and could be misconstrued as the Agency’s imposing a specific control requirement 

in contravention of the Virginia decision.226 As the commenter elsewhere itself argued, states 

have broad discretion to develop SIP provisions to meet the objectives of the CAA, so long as 

those provisions also meet the legal requirements of the CAA. To the extent that a state would 

prefer to have emission limitations that apply continuously, without higher numerical levels or 

specific technological controls or work practice standards applicable during modes of operation 

such as startup and shutdown, that is the prerogative of the state, so long as the revised SIP 

provision otherwise meets CAA requirements. If a state determines that it is reasonable to 

require a source to meet a specific emission limitation on a continuous basis and also decides to 

rely on its own enforcement discretion to determine whether a violation of that emission limit 

should be subject to enforcement, then the EPA believes that to do so is within the discretion of 

the state. 

q. Comments that the EPA’s action on the Petition is inconsistent with the Credible 

Evidence Rule. 

Comment: A number of commenters raised concerns based upon how the EPA’s 

statements in the February 2013 proposal relate to the Credible Evidence Rule issued in 1997.227

For example, one commenter argued that throughout the February 2013 proposal, when the EPA 

stated that excess emissions during SSM events should be treated as “violations” of the 

 

226 See Virginia, et al. v. EPA, 108 F.3d 1397 (D.C. Cir. 1997) (SIP call remanded and vacated 

because, inter alia, the EPA had issued a SIP call that required states to adopt a particular control 

measure for mobile sources). 

227 See “Credible Evidence Revisions, Final Rule,” 62 FR 8314 (February 24, 1997). For clarity, 

the EPA emphasizes that it is in no way reopening, revising or otherwise amending the Credible 

Evidence Rule in this action. The EPA is merely responding to commenters who characterized 

the relationship between Agency statements in that rulemaking action and this SIP call action. 
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applicable SIP emission limitations, the Agency was contradicting the Credible Evidence Rule 

and other provisions of law. The commenter emphasized that the determination of whether 

excess emissions during an SSM event are in fact a “violation” of the applicable SIP provisions 

must be made using the appropriate reference test method. In addition, the commenter asserted 

that whether any other form of information may be used as “credible evidence” of a violation 

must be evaluated by the trier of fact in a specific enforcement action. Another commenter raised 

a different argument based on the Credible Evidence Rule, claiming that the EPA’s statements in 

the preamble to that rulemaking contradict the EPA’s statements in the February 2013 proposal 

and support the need for exemptions for emissions during SSM events. The implication of the 

commenter is that any such EPA statements in connection with the Credible Evidence Rule 

would negate the Agency’s interpretation of the statutory requirements for SIP provisions as 

interpreted in the SSM Policy since at least 1982, the decision of the court in the Sierra Club

case or any other actions such as the recent issuance of EPA regulations with no such SSM 

exemptions. 

Response: The EPA agrees, in part, with the commenters who expressed concern that the 

Agency’s statements in the February 2013 proposal could be misconstrued as a definitive 

determination that the excess emissions during any and all SSM events are automatically a 

violation of the applicable emission limitation, without factual proof of that violation, and 

without the existence and scope of that violation being decided by the appropriate trier of fact. 

The EPA of course agrees that the alleged violation of the applicable SIP emission limitation, if 

not conceded by the source, must be established by the party bearing the burden of proof in a 

legal proceeding. The degree to which evidence of an alleged violation may derive from a 

specific reference method or any other credible evidence must be determined based upon the 
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facts and circumstances of the exceedance of the emission limitations at issue.228 The EPA 

presumed that this most basic principle of enforcement actions under the CAA was a given but 

wishes to make this point clearly in this final action to avoid any unintended confusion between 

the legal standard creating the enforceable obligation and the evidentiary standard for proving a 

violations of that obligation. 

The EPA’s general statements in the February 2013 proposal, the SNPR and this final 

action about treatment of SSM emissions as a violation pertain to another basic principle, i.e., 

that SIP provisions cannot treat emissions during SSM events as exempt, because this is 

inconsistent with CAA requirements. Thus, when the EPA explains that these emissions must be 

treated as “violations” in SIP provisions, this is meant in the sense that states with SSM 

exemptions need to remove them, replace them with alternative emission limitations that apply 

during startup and shutdown or eliminate them by revising the emission limitation as a whole. 

Once impermissible SSM exemptions are removed from the SIP, then any excess emissions 

during such events may be the subject of an enforcement action, in which the parties may use 

any appropriate evidence to prove or disprove the existence and scope of the alleged violation 

and the appropriate remedy for an established violation. To be clear, the fact that these emissions 

are currently exempt through inappropriate SIP provisions is a deficiency that the EPA is 

addressing in this action. Thus, the EPA disagrees with the commenters’ suggestion that these 

emissions are never to be treated as violations simply because a deficient SIP provision currently 

 

228 For example, the degree to which data from continuous opacity monitoring systems (COMS) 

is evidence of violations of SIP opacity or PM mass emission limitations is a factual question 

that must be resolved on the facts and circumstances in the context of an enforcement action. 

See, e.g., Sierra Club v. Pub. Serv. Co. of Colorado, Inc., 894 F. Supp. 1455 (D. Colo. 1995) 

(allowing use of COMS data to prove opacity limit violations). 
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includes an SSM exemption. Once the SIP provisions are corrected, the excess emissions may be 

addressed through the legal structure for establishing an enforceable violation, which then may 

be proven using appropriate evidence, including test method evidence or other credible evidence. 

This means that excess emissions that occur during an SSM event will be treated for enforcement 

purposes in exactly the same manner as excess emissions that occur outside of SSM events. The 

EPA acknowledges that the limitation that applies during a startup or shutdown event might 

ultimately be different (whether higher or lower) than the limitation that applies at other times, if 

the state elects to replace the SSM exemption with an appropriate alternative emission limitation 

in response to this SIP call action. 

The EPA also disagrees with commenters who claimed that statements by the Agency in 

the Credible Evidence Rule final rule preamble support the inclusion of exemptions for SSM 

events in SIP provisions. The commenter is correct that at that time, the EPA held the view that 

emission limitations in its own NSPS could be considered “continuous,” notwithstanding the fact 

that they contained “specifically excused periods of noncompliance” (i.e., exemptions from 

emission limitations during SSM events).229 Similarly, at that time the EPA relied on a number 

of reported court decisions discussed in the preamble for the Credible Evidence Rule for 

determining at that time that NSPS could contain such exemptions in order to make the emission 

limitations “reasonable.” However, after the court’s decision in the Sierra Club case interpreting 

the definition of emission limitation in section 302(k), these statements are no longer accurate 

and thus do not apply to EPA’s SIP call action in this notice. 

 

229 Id., 62 FR 8314, 8323–24. 
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First, the EPA notes that these prior statements related to the Credible Evidence Rule 

specifically addressed not SIP provisions but rather the provisions of the Agency’s own 

technologically based NSPS. The statements in the notice make no reference to SIP provisions, 

which is unsurprising given that EPA’s SSM Policy at the time indicated that no such SSM 

exemptions are appropriate in SIP provisions. Second, the EPA’s justification for exemptions 

from emission limitations during SSM events in NSPS was obviously made prior to the 2008 

decision of the court in the Sierra Club case. The EPA’s interpretation of the statute and the case 

law to justify exemptions for emissions during SSM events in that 1997 notice is no longer 

correct. Finally, the EPA in its own new NESHAP and NSPS regulations is now providing no 

exemptions for emissions during SSM events and is imposing specific numerical limitations or 

other control requirements on sources that apply to affected sources at all times, including during 

SSM events.230 Thus, the statements in the 1997 Credible Evidence Rule preamble relied upon 

by commenters do not render the EPA’s interpretation of the CAA with respect to SSM 

exemptions in SIP provisions in this action incorrect. 

r. Comments that exemptions in opacity standards should be permissible because 

opacity is not a NAAQS pollutant. 

Comment: Many state and industry commenters argued that the EPA should interpret the 

CAA to allow SIP provisions that impose opacity emission limitations to contain exemptions for 

SSM events or for other modes of source operation. The reasons given by commenters ranged 

broadly, but they included assertions that opacity is not a criteria pollutant, that opacity 

 

230 See, e.g., 40 CFR 60.42Da, where paragraph (e)(1) applies a numerical PM emission 

limitation at all times except during periods of startup and shutdown, and paragraph (e)(2) 

applies work practice standards during periods of startup and shutdown. 
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limitations serve no purpose other than as a tool to monitor PM control device performance, that 

there is no reliable correlation between opacity and PM mass, that there are circumstances during 

which sources may not be capable of meeting the otherwise applicable SIP opacity standards and 

that opacity is not an “air pollutant.” Commenters also argued that because SIP opacity standards 

were originally established when the NAAQS applied to “total suspended particles” (TSP), 

rather than the current PM10 and PM2.5, this alone should be a reason to allow SSM exemptions 

now that the NAAQS have been revised and the indicator species changed. Some of the 

commenters acknowledged that their underlying concern is that requirements for COMS on 

certain sources have rendered it much easier to monitor exceedances of SIP opacity limits and to 

bring enforcement actions for alleged violations. 

Response: The EPA agrees with many of the points made by commenters but not with the 

conclusion that the commenters drew from these points, i.e., that exemptions for SSM events are 

appropriate in SIP provisions that impose opacity emission limitations. 

First, although the EPA agrees that opacity itself is not a criteria pollutant and that there 

is thus no NAAQS for opacity, that does not mean that SIP opacity limitations are not “emission 

limitations” subject to the requirements of section 110(a)(2)(A) and do not need to be 

continuous. As the commenters often conceded, opacity is a surrogate for PM emissions for 

which there are NAAQS, and opacity has served this purpose since the beginning of the SIP 

program in the 1970s. SIP provisions that impose opacity emission limitations often date back to 

the earliest phases of the SIP program. From the outset, such opacity limitations have provided 

an important regulatory tool for implementing the PM NAAQS and for limiting PM emissions 

from sources. To this day, states continue to use opacity limitations in SIP provisions and the 

EPA continues to use opacity limitations in its own NSPS and NESHAP regulations, as 
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necessary, for specific source categories.231 EPA regulations applicable to SIPs explicitly define 

the term “emission limitation” to include opacity limits.232 It is also important to note that these 

SIP provisions impose opacity emission limitations that sources must meet independently; i.e., 

opacity limitations are independent “emission limitations” under section 110(a)(2)(A) that must, 

consistent with section 302(k), “limit[] the quantity, rate, or concentration of emissions of air 

pollutants on a continuous basis.” These opacity emission limitations in SIP provisions are not 

stated conditionally as opacity limits that sources do not need to meet if they are otherwise in 

compliance with PM mass emission limitations or with any other CAA requirements. Thus, the 

fact that opacity is not itself a criteria pollutant is irrelevant. 

Second, although the EPA agrees that SIP opacity limitations also provide an important 

means of monitoring control device performance and thus indirectly provide a means to monitor 

compliance with PM emission limitations as well, this does not mean that opacity limits do not 

need to meet the statutory requirements for SIP emission limitations. Historically, opacity limits 

have been an important tool for implementation of the PM NAAQS, and in particular for the 

implementation and enforcement of PM mass limitations on sources to help attain and maintain 

the PM NAAQS. The EPA agrees that opacity is a useful tool to indicate overall operation and 

maintenance of a source and its emission control devices such as electrostatic precipitators or 

baghouses. SIP opacity limitations provided this tool even before modern instruments that 

 

231 See, e.g., 40 CFR 60.42Da(b). The EPA’s revised NSPS for this category imposes an opacity 

limit of 20 percent at all times, except for one 6-minute period per hour when the opacity may 

rise to 27 percent. Notably, as an option, sources may elect to install PM CEMS and be subject 

only to the revised particulate matter emission limitation. 

232 See 40 CFR 51.100(z) (defining the term “emission limitation” as limits on “the quantity, rate, 

or concentration of emissions of air pollutants on a continuous basis, including any requirements 

which limit the level of opacity”). 
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measure PM emissions on a direct, continuous basis existed. At a minimum, elevated opacity 

indicates potential problems with source design, operation or maintenance, or potential problems 

with incorrect operation of pollution control devices, especially at the elevated levels of many 

existing opacity standards. Well-run sources should be in compliance with the typical opacity 

limits of 20 percent with set amounts of time per hour allowed at somewhat higher opacity 

limits. Higher opacity can be indicative of problems that justify further investigation by sources 

and regulators, such as conducting a stack test to determine compliance with PM mass emission 

limitations. Not all sources have or will have PM CEMS, or have PM CEMS at all emission 

points, to monitor PM emissions directly, nor do PM CEMS necessarily obviate the need for 

opacity standards to regulate condensables, and thus there is a continued need for opacity 

emission limitations in SIPs. The continued need for SIP opacity limitations for this and other 

purposes contradicts the commenters’ arguments concerning the validity of SSM exemptions. 

Third, the EPA agrees that the precise correlation between opacity and PM mass 

emissions is not always known for a specific source under all operating conditions, unless there 

is parallel testing and measurement of the opacity and the PM emissions to determine the 

correlation at that particular source. Similarly, parametric monitoring can be used to establish 

such a correlation. Nevertheless, there is commonly a positive correlation between PM and 

opacity and thus elevated opacity is often indicative of additional PM emissions from a source. 

Even in those instances where a precise correlation is not available, however, the use of opacity 

as a means to assure the reduction of PM emissions and to monitor source compliance remains a 

valid approach to regulation of PM from sources. In any event, the absence of a precise 

correlation between opacity and PM does not justify the complete exemptions from SIP opacity 

limitations during SSM events that the commenters advocate and instead suggests that it may be 
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appropriate to replace such exemptions with valid and enforceable alternative numerical 

limitations or other control requirements as a component of the SIP opacity emission limitation 

that applies during startup and shutdown. Opacity emission limitations in SIPs must meet the 

statutory requirements for emission limitations. 

Fourth, the EPA agrees with commenters that for some sources some PM controls cannot 

operate, or operate at full effectiveness and ideal efficiency, during startup and shutdown. 

Accordingly, as the commenters implicitly recognized, the resulting increases in PM emissions 

can result in elevated opacity and thus exceedances of the applicable SIP opacity emission 

limitations. In those situations where it is true that no additional emissions controls are available 

or would function more effectively to reduce PM emissions, and hence to reduce opacity, it may 

be appropriate for states to consider imposing an alternative opacity emission limitation 

applicable during startup and shutdown. As discussed in section VII.B.2 of this document, the 

EPA provides recommendations to states concerning how to develop such alternative emission 

limitations. To the extent that sources believe that a SIP provision with a higher opacity level for 

startup and shutdown may be justified, they may seek these alternative limitations from the state 

and they can presumably advocate for opacity standards that are tailored to reflect the correlation 

between PM mass and opacity at a specific source. Significantly, however, even if it is 

appropriate to impose a somewhat higher opacity limitation for some sources during specifically 

defined modes of operation such as startup and shutdown, that does not justify the total 

exemptions from SIP opacity emission limitations during SSM events that the commenters 

advocated. To provide total exemptions from SIP opacity emission limitations during SSM 

events does not provide any incentive for sources to be better designed, operated, maintained and 

controlled to reduce emissions, nor does it comply with the most basic requirement that SIP 
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emission limitations be continuous in accordance with section 302(k). As explained in section 

X.B of this document, the SIP revisions in response to this SIP call action will need to be 

consistent with the requirements of sections 110(k)(3), 110(l) and 193 as well as any other 

applicable requirements. 

Fifth, the EPA notes that few commenters seriously argued that SIP provisions for 

opacity do not fit within the plain language of section 110(a)(2)(A) or the definition of “emission 

limitation” in section 302(k) or in EPA regulations applicable to SIP provisions. Section 

110(a)(2)(A) requires SIPs to contain such enforceable emission limitations “as may be 

necessary and appropriate to meet the applicable requirements of” the CAA. Opacity limitations 

in SIP provisions are necessary and appropriate for a variety of reasons already described, 

including as a means to reduce PM emissions, as a means to monitor source compliance and to 

provide for more effective enforcement. Opacity limitations in SIP provisions also easily fit 

within the concept of a limit on the “quantity, rate or concentration of air pollutants” that relates 

to the “operation or maintenance of a source to assure continuous emission reduction and any 

design, equipment, work practice or operational standard” under the CAA, as provided in section 

302(k). The term “air pollutant” is defined broadly in section 302(g) to mean “any air pollution 

agent or combination of such agents, including any physical, chemical, biological, radioactive ... 

substance or matter which is emitted into or otherwise enters the ambient air.” Even if opacity is 

not itself an air pollutant, it is clearly a means of monitoring and limiting emissions of PM from 

sources and is thus encompassed within the definition of “emission limitation” in section 
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302(k).233 Significantly, existing EPA regulations applicable to SIP provisions already explicitly 

define the term “emission limitation” to include opacity limitations.234 

Finally, the EPA does not agree with commenters who argued that because SIP opacity 

limitations were often originally imposed when the PM NAAQS was for TSP, it is legally 

acceptable to have exemptions for emissions during SSM events now that the PM NAAQS use 

PM10 and PM2.5 as the indicator species. On a factual level, it is obvious that SIP provisions for 

opacity limitations are expressed in terms of percentage “opacity” unrelated to the size of the 

particles. Opacity represents the degree to which emissions reduce the transmission of light and 

obscures the view of an object in the background. In general, the more particles which scatter or 

absorb light that passes through an emissions point, the more light will be blocked, thus 

increasing the opacity percentage of the emissions plume. The EPA agrees that variables such as 

the size, number and composition of the particles in the emissions can result in variations in the 

percentage of opacity. Notwithstanding the changes in the NAAQS, however, both states and the 

EPA have continued to rely on opacity limitations because they serve the same purposes for the 

current PM10 and PM2.5 NAAQS (and other purposes such as the regulation of HAPs under 

section 112) that they previously did for the TSP NAAQS. Indeed, as the PM NAAQS have been 

revised to provide better protection of public health, the need for such opacity limitations 

continues unless there is a better means to monitor source compliance, such as PM CEMS. As 

with other SIP emission limitations, the EPA interprets the CAA to preclude SSM exemptions in 

opacity standards. 

 

233 See Sierra Club v. TVA, 430 F.3d 1337, 1340 (11th Cir. 2005). 

234 See 40 CFR 51.100(z). 
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s. Comments that exemptions from SIP opacity limitations for excess emissions 

during SSM events should be allowed because such emissions are difficult to monitor or to 

control. 

Comment: Several commenters argued that the EPA’s proposal of a SIP call for SIP 

opacity emission limitations that include an SSM exemption is arbitrary and capricious because 

it is difficult or impossible to monitor or measure opacity during SSM events. According to 

commenters, there is no compliance methodology to determine whether opacity limitations are 

met during SSM events and this is the reason that the EPA’s own general provisions for NSPS 

and NESHAP exclude emissions during SSM events as “not representative” of source operation. 

In the absence of a specific methodology to demonstrate compliance, the commenters argued that 

expecting sources to comply with any opacity emission limitations during SSM events is 

arbitrary and capricious. The commenters asserted that in light of this, the EPA must interpret the 

CAA to allow exemptions for SSM events in SIP opacity provisions. 

A number of commenters also argued that because emission controls for PM do not 

function, or do not function as effectively or efficiently, during certain modes of source 

operation, the EPA should interpret the CAA to permit exemptions for SSM events in opacity 

emission limitations. Many commenters explained that certain types of emission controls at 

certain types of sources only operate at specific temperatures or under specific conditions. For 

example, many commenters stated that existing pollution control devices on certain categories of 

stationary sources do not operate, or do not operate as effectively or efficiently, during startup 

and shutdown. Based upon this assertion, the commenters argued that the EPA should interpret 

the CAA to allow total exemptions from SIP opacity emission limitations during such periods. 
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Commenters also characterized the EPA’s February 2013 proposal as “particularly 

unreasonable” with respect to SSM exemptions in SIP opacity limitations, because those 

limitations should be allowed to exclude elevated opacity during periods when PM emissions 

controls devices are “not expected to operate correctly.” According to commenters, treating the 

higher opacity during SSM events “as a violation simply because it is indicating something that 

is expected is ridiculous.” As an example, the commenters specifically mentioned occurrences 

such as when a source’s electrostatic precipitator (ESP) is not functioning or is not functioning 

properly as periods during which there should be an exemption from SIP opacity emission 

limitations. 

Response: The EPA agrees with some of the points made by commenters but does not 

agree with the conclusions that the commenters drew from these points, i.e., that alleged 

difficulties in monitoring, measuring or controlling opacity during some modes of source 

operation in general justify complete exemptions from opacity emission limitations during SSM 

events. 

First, the EPA does not agree with the argument that there is no “compliance 

methodology” available for purposes of verifying compliance with SIP opacity limitations. Since 

the earliest phases of the SIP program, Reference Method 9 has been available as a means of 

verifying a source’s compliance with applicable SIP opacity emission limitations. Whatever 

quibbles the commenters may have with this test method, it is a valid method and it continues to 

be used as a means of verifying source compliance with opacity limitations and a source of 
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evidence for determining whether there are violations of such emission limitations.235 Sources 

routinely monitor and certify to their compliance with SIP opacity limitations based upon 

Method 9. In addition, COMS have been available, and in some cases are required, as another 

means of monitoring emissions and verifying compliance with opacity emission limitations. 

With respect to COMS, commenters expressed concerns that they are not always accurate, are 

not always properly calibrated or are not always the reference test method for SIP opacity 

emission limitations, and other similar arguments. In this rulemaking, the EPA is not addressing 

these allegations concerning COMS but merely noting that COMS are an available means of 

monitoring opacity from sources and in appropriate circumstances can provide data meeting the 

EPA’s criteria as credible evidence to be used to determine compliance with emission 

limitations. 

Second, the EPA does not agree that the fact that its regulations concerning performance 

tests in 40 CFR 63.7(e) for NESHAP and in 40 CFR 60.8(c) for NSPS exclude SSM emissions 

for purposes of evaluation of emissions under normal operating conditions provides a 

justification for SSM exemptions from opacity emission limitations in SIP provisions. The D.C. 

Circuit decision in Sierra Club has already indicated that such exemptions are not permissible in 

emission limitations and vacated the general provisions applicable to NESHAP. In the case of 

the exemption language in 40 CFR 60.8(c) relevant to NSPS, the EPA acknowledges that it has 

 

235 The EPA notes that one commenter characterized SIP opacity limits as “archaic” and 

suggested that the Agency should issue a SIP call requiring their removal from SIPs entirely. 

Unless and until regulators and sources have a better means of monitoring compliance with PM 

emission limitations on a continuous basis, such as through installation of PM CEMS, the EPA 

believes that opacity limits will continue to be a necessary part of emission limitations. There 

will continue to be sources of emissions for which it will not be cost-effective or technologically 

viable to require the installation of PM CEMS or for which opacity standards will be needed as a 

means of regulating condensables. 
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not yet taken action to revise the language to eliminate that exemption. However, in 

promulgating new NSPS regulations subsequent to the Sierra Club decision, the EPA is 

including emission limitations for newly constructed, reconstructed and modified sources that 

apply continuously and including provisions expressly stating that the SSM exemptions in the 

General Provisions do not apply. The EPA notes that the commenter is also in error because the 

performance tests are intended to be a means of evaluating emissions from sources during 

periods that are representative of source operation. 

Third, the EPA does not agree with the premise that because certain forms or types of 

emission controls do not work, or do not work as effectively or efficiently, during certain modes 

of operation at some sources, it necessarily follows that sources should be totally exempt from 

emission limitations during such periods. The EPA interprets the CAA to require that SIP 

emission limitations be continuous. As explained in section VII.A of this notice, emission 

limitations do not necessarily need to be expressed numerically, can have higher numerical levels 

during certain modes of operation, and may be composed of a combination of numerical 

limitations, specific technological control requirements and/or work practice requirements during 

certain modes of operation, so long as these emission limitations meet applicable CAA 

stringency requirements and are legally and practically enforceable. If it is factually accurate that 

a given source category requires a higher opacity limit during periods such as startup and 

shutdown, then the state may elect to develop one consistent with other CAA requirements. The 

EPA has provided guidance to states with criteria to consider in revising their SIP provisions to 

replace exemptions with an appropriate alternative emission limitation for such purposes. The 

EPA emphasizes that even if it is the case that existing control measures cannot operate, or 

cannot operate as effectively or efficiently, during startup and shutdown at a particular source, 
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this does not legally justify a complete exemption from SIP emission limitations and may merely 

indicate that additional emission controls or work practices are necessary when the existing 

control measures are insufficient to meet the applicable SIP emission limitation. The EPA is 

taking this approach with its own recent NSPS and NESHAP regulations, when appropriate, in 

order to ensure that its own emission limitations are consistent with CAA requirements. 

Finally, the EPA also disagrees with the logic of commenters that argued in favor of 

exemptions from SIP opacity limitations during periods when a source is most likely to violate 

them, e.g., when the source’s control devices are not functioning. Even if exemptions from SIP 

opacity emission limitations were legally permissible under the CAA, which they are not, it 

would be illogical to excuse compliance with the standards during the precise periods when 

opacity standards are most needed to monitor sources and assure compliance with SIP emission 

limitations; i.e., it would be illogical to require no emission controls when the sources are most 

likely to be emitting the most air pollutants. Inclusion of exemptions for exceedances of SIP 

opacity limitations during such periods would remove incentives to design, maintain and operate 

the source correctly in order to assure that it meets the applicable SIP emission limitations. By 

exempting excess emissions during such events, the provision would undermine the enforcement 

structure of the CAA in section 113 and section 304, through which the air agency, the EPA and 

citizens are authorized to assure that sources meet their obligations. 

t. Comments that exemptions in SIP opacity limitations should be permissible for 

“maintenance,” “soot-blowing” or other normal modes of source operation. 

Comment: A number of industry commenters argued that the EPA should interpret the 

CAA to allow exemptions from SIP opacity limitations for “maintenance.” The commenters 

stated that during maintenance, sources must shut down operations and control devices while the 
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source is cleaned or repaired. During such periods, the commenters explained, a ventilation 

system operated to protect workers at the source could result in monitored exceedances of a SIP 

opacity limitation. Commenters specifically argued that although COMS data may suggest 

violations of opacity standards during such periods, the fact that the source is not combusting 

fuel during maintenance should mean that the opacity emission limitation does not apply at such 

times. According to commenters, opacity limitations are only intended to reflect the performance 

of pollution control equipment while the source is operating and thus have no relevance during 

periods of maintenance. Other commenters made comparable arguments with respect to sootblowing, asserting that the high opacity levels during this activity are “indicative of normal ESP 

operation, not poor performance.” In other words, the commenters argued that opacity 

limitations should contain complete exemptions for opacity emitted during soot-blowing on the 

theory that the elevated emissions during this mode of operation show that the control measure 

on a source is functioning properly. The commenters further argued that considering emissions 

during soot-blowing for purposes of PM limitations is appropriate, but not for purposes of 

opacity limitations, because of the way in which regulators developed the respective emission 

limitations. 

Response: The EPA does not agree that exemptions from SIP opacity limitations are 

appropriate for any mode of source operation, whether during SSM events or during other 

normal, predictable modes of source operation. To the extent that there are legitimate 

technological reasons why sources are able to meet only a higher opacity limitation during 

certain modes of operation, it does not follow that this constraint justifies complete exemption 

from any standard or any alternative technological control or work practice in order to reduce 

opacity during such periods. Providing a complete exemption for opacity during these modes of 
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source operation, and no specific alternative emission limitation during such periods, removes 

incentives for sources to be properly designed, maintained and operated to reduce emissions 

during such periods. 

With respect to maintenance, the EPA does not agree with commenters that total 

exemptions from opacity emission limitations during such activities are consistent with CAA 

requirements for SIP provisions. As the EPA has stated repeatedly in its interpretation of the 

CAA in the SSM Policy, maintenance activities are predictable and planned activities during 

which sources should be expected to comply with applicable emission limitations.236 The 

premise of the commenters advocating for such exemptions for all emissions during maintenance 

is evidently that nothing can be done to limit PM emissions and thus limit opacity during 

maintenance activities, and the EPA disagrees with that general premise. To the extent 

appropriate, however, states may elect to create alternative emission limitations applicable to 

opacity during maintenance periods, so long as they are consistent with CAA requirements. The 

EPA provides recommendations for alternative emission limitations in section VII.B.2 of this 

document. 

With respect to soot-blowing, the EPA likewise does not agree that total exemptions from 

opacity limitations during such periods are consistent with CAA requirements. As with 

maintenance in general, soot-blowing is an intentional, predictable event within the control of the 

source. The commenters’ implication is that nothing whatsoever could be done to limit opacity 

 

236 See 1982 SSM Guidance at Attachment p. 2; 1983 SSM Guidance at Attachment p. 3. The 

EPA notes that it also did not interpret the CAA to permit affirmative defense provisions for 

planned events under its prior 1999 SSM Guidance on the grounds that sources should be 

expected to operate in accordance with applicable SIP emission limitations during maintenance. 

This interpretation was upheld in Luminant Generation Co. LLC v. EPA, 714 F,3d 841 (5th Cir. 

2013). 
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during such activities, and the EPA believes that this is both inaccurate and not a justification for 

sources’ being subject to no standards whatsoever during soot-blowing. In addition, the EPA 

disagrees with the commenters’ claim that exemptions from opacity emission limitations during 

soot-blowing are legally permissible because this allegedly shows that the control devices for 

opacity and PM are in fact performing correctly. This argument incorrectly presupposes that the 

sole reason for SIP opacity emission limitations is as a means of better evaluating control 

measure performance. This is but one reason for SIP opacity limitations. Moreover, the EPA 

notes, excusing opacity during soot-blowing has the diametrically opposite effect of the actual 

purpose of the control devices and can result in much higher emissions as opposed to 

encouraging limiting these emission with other forms of controls. 

Finally, the EPA notes, the commenters’ argument that whether opacity limitations 

should apply during soot-blowing depends upon whether the emissions were or were not 

accounted for in the applicable PM emissions is also based upon an incorrect premise. Even if 

the PM emission limitation applicable to a source was developed to include the emissions during 

soot-blowing specifically, it does not follow that sources should be completely exempted from 

opacity limitations during such periods. As the commenters themselves frequently 

acknowledged, when compared to other enforcement tools, SIP opacity provisions often provide 

a much more effective and continuous means of determining source compliance with SIP PM 

limitations and control measure performance. A typical SIP opacity provision imposes an 

emission limitation such as 20 percent opacity at all times, except for 6 minutes per hour when 

those emissions may rise to 40 percent opacity. Well-maintained and well-operated sources 

should be able to meet such SIP opacity limitations. Given that properly designed, maintained 

and operated sources should typically have opacity substantially below these levels, elevated 
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opacity at a source is a good indication that the source may not be in compliance with its 

applicable PM limitations. 

u. Comments that elimination of exemptions from SIP opacity emission limitations 

during SSM events will compel states to alter the averaging period of opacity limitations so as to 

allow sources to have elevated emissions during SSM events. 

Comment: Commenters argued that if exemptions for excess emissions during SSM 

events are not legally permissible in SIP opacity emission limitations, then states will have no 

option but to alter the existing opacity limitations. The commenters argued that if the SSM 

exemptions are removed, then the averaging time should be “greatly extended” and the 

numerical limits “should be significantly increased.” 

Response: The EPA agrees that SIP provisions for opacity that contain exemptions for 

SSM events at issue in this action must be revised to eliminate the exemptions. States may elect 

to do this by merely removing the exemptions, by replacing the exemptions with appropriate 

alternative emission limitations that apply in place of the exemptions or by a total overhaul of the 

emission limitation as the commenters evidently advocate. The EPA disagrees, however, with 

the commenters’ contentions that removal of the SSM exemptions must necessarily result in 

extensions of the averaging time or increases of the numerical levels in the existing SIP opacity 

emission limitations. In some cases, extension of the averaging period and elevation of the 

numerical limitations may in fact be appropriate. In other cases, however, it may instead be 

appropriate to reduce the existing numerical opacity limitations, given improvements in control 

technology since the original imposition of the limits and the need for additional PM emission 

reductions from the affected sources due to more recent revisions to the PM NAAQS. Thus, the 

EPA notes, a total revision of some of the SIP opacity limitations at issue in this action may 
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indeed be the proper course for states to consider. The implications of the commenters’ 

argument, however, are that existing opacity limitations will automatically need to be revised in 

order to allow sources to continue to emit as usual and that states and sources may ignore 

improvements that have been made in source design, operation, maintenance or controls to 

reduce emissions. The EPA emphasizes that the removal of impermissible SSM exemptions 

should not be perceived as an opportunity to provide new de facto exemptions for these 

emissions by manipulation of the averaging time and the numerical level of existing opacity 

emission limitations. 

In any event, the EPA is not deciding in this final action how states must revise SIP 

opacity emission limitations but is merely issuing a SIP call directing the affected states to 

eliminate existing automatic and discretionary exemptions for excess emissions during SSM 

events. The affected states will elect how best to respond to this SIP call, whether by simply 

removing the exemptions, by replacing the exemptions with appropriate alternative emission 

limitations applicable to startup and shutdown or other normal modes of operation or by a 

complete overhaul of the SIP provision in question. In particular, where the affected sources are 

located in designated nonattainment areas, there may be a need to evaluate additional controls 

that are needed for attainment planning purposes that were not necessary when the emission 

limitation was first adopted. Whichever approach a state determines to be most appropriate, the 

resulting SIP submission to revise the existing deficient provisions will be subject to review by 

the EPA pursuant to sections 110(k)(3), 110(l) and 193. Considerations relevant to this issue are 

discussed in section X.B of this document. 

B. Alternative Emission Limitations During Periods of Startup and Shutdown 

1. What the EPA Proposed 
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In the February 2013 proposal, the EPA reiterated its longstanding interpretation of the 

CAA that SIP provisions cannot include exemptions from emission limitations for emissions 

during SSM events but may include different requirements that apply to affected sources during 

startup and shutdown. Since the 1982 SSM Guidance, the EPA has clearly stated that startup and 

shutdown are part of the normal operation of a source and should be accounted for in the design 

and operation of the source. Thus, the EPA has long concluded that sources should be required to 

meet the applicable SIP emission limitations during normal modes of operation including startup 

and shutdown.237 In the 1983 SSM Guidance, the EPA explained that it may be appropriate to 

exercise enforcement discretion for violations that occur during startup and shutdown under 

proper circumstances. In the 1999 SSM Guidance, the EPA further explained that it interprets the 

CAA to permit SIP emission limitations that include alternative emission limitations specifically 

applicable during startup and shutdown. In the context of making recommendations to states for 

how to address emissions during startup and shutdown, the EPA provided seven criteria for 

states to evaluate in establishing appropriate alternative emission limitations. The specific 

purpose for these recommendations was to take into account technological limitations that might 

prevent compliance with the otherwise applicable emission limitations. As explained in detail in 

the February 2013 proposal, the EPA did not intend these criteria to be the basis for the creation 

 

237 Some commenters on the February 2013 proposal focused great attention on whether startup 

and shutdown are modes of “normal” source operation. The EPA assumes that every source is 

designed, maintained and operated with the expectation that the source will at least occasionally 

start up and shut down, and thus these modes of operation are “normal” in the sense that they are 

to be expected. The EPA used this term in the ordinary sense of the word to distinguish between 

such predictable modes of source operation and genuine “malfunctions,” which are by definition 

supposed to be unpredictable and unforeseen events that could not have been precluded by 

proper source design, maintenance and operation. 
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of exemptions from SIP emission limitations during startup and shutdown, because the Agency 

interprets the CAA to prohibit such exemptions. 

In the February 2013 proposal, the EPA also repeated its guidance concerning 

establishment of alternative emission limitations that apply to sources during startup and 

shutdown, in those situations where the sources cannot meet the otherwise applicable SIP 

emission limitations. As explained in section VII.A of the February 2013 proposal, the EPA 

interprets the CAA to require that SIP emission limitations must be continuous and thus to 

prohibit exemptions for emissions during startup and shutdown. This does not, however, mean 

that every SIP emission limitation must be expressed as a numerical limitation or that it must 

impose the same limitations during all modes of source operation. The EPA’s interpretation of 

the CAA with respect to SIP provisions is that SIP emission limitations: (i) do not need to be 

numerical in format; (ii) do not have to apply the same limitation (e.g., numerical level) at all 

times; and (iii) may be composed of a combination of numerical limitations, specific 

technological control requirements and/or work practice requirements, with each component of 

the emission limitation applicable during a defined mode of source operation. Regardless of how 

an air agency elects to express the emission limitation, however, the emission limitation must 

limit emissions from the affected sources on a continuous basis. Thus, if there are different 

numerical limitations or other control requirements that apply during startup and shutdown, those 

must be clearly stated components of the emission limitation, must meet the applicable level of 

control required for the type of SIP provision (e.g., be RACT for sources located in 

nonattainment areas) and must be legally and practicably enforceable. 

2. What is Being Finalized in This Action 
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The EPA is reiterating its interpretation of the CAA to allow SIP emission limitations to 

include components that apply during specific modes of source operation, such as startup and 

shutdown, so long as those components together create a continuously applicable emission 

limitation that meets the relevant substantive requirements and requisite level of stringency for 

the type of SIP provision at issue and is legally and practically enforceable. In addition, the EPA 

is updating the specific recommendations to states for developing such alternative emission 

limitations described in the February 2013 proposal, by providing in this notice some additional 

explanation and revisions to the text of its recommended criteria regarding alternative emission 

limitations. 

The EPA’s longstanding position is that the CAA does not allow SIP provisions that 

include exemptions from emission limitations for excess emissions that occur during startup and 

shutdown. The EPA reiterates that exemptions from SIP emission limitations are also not 

permissible for excess emissions that occur during other periods of normal source operation. A 

number of SIP provisions identified in the Petition create automatic or discretionary exemptions 

from otherwise applicable emission limitations during periods such as “maintenance,” “load 

change,” “soot-blowing,” “on-line operating changes” or other similar normal modes of 

operation. Like startup and shutdown, the EPA considers all of these to be modes of normal 

operation at a source, for which the source can be designed, operated and maintained in order to 

meet the applicable emission limitations and during which the source should be expected to 

control and minimize emissions. Accordingly, exemptions for emissions during these periods of 

normal source operation are not consistent with CAA requirements. Excess emissions that occur 

during planned and predicted periods should be treated as violations of any applicable emission 

limitations. 
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However, the EPA interprets the CAA to allow SIPs to include alternative emission 

limitations for modes of operation during which an otherwise applicable emission limitation 

cannot be met, such as may be the case during startup or shutdown. The alternative emission 

limitation, whether a numerical limitation, technological control requirement or work practice 

requirement, would apply during a specific mode of operation as a component of the 

continuously applicable emission limitation. For example, an air agency might elect to create an 

emission limitation with different levels of control applicable during specifically defined periods 

of startup and shutdown than during other normal modes of operation. All components of the 

resulting emission limitation must meet the substantive requirements applicable to the type of 

SIP provision at issue, must meet the applicable level of stringency for that type of emission 

limitation and must be legally and practically enforceable. The EPA will evaluate a SIP 

submission that establishes a SIP emission limitation that includes alternative emission 

limitations applicable to sources during startup and shutdown consistent with its authority and 

responsibility pursuant to sections 110(k)(3), 110(l) and 193 and any other CAA provision 

substantively germane to the SIP revision. Absent a properly established alternative emission 

limitation for these modes of operation, a source should be required to comply with the otherwise 

applicable emission limitation. 

In addition, the EPA is providing in this notice some additional explanation and 

clarifications to its recommended criteria for developing alternative emission limitations 

applicable during startup and shutdown. The EPA continues to recommend that, in order to be 

approvable (i.e., meet CAA requirements), alternative requirements applicable to the source 

during startup and shutdown should be narrowly tailored and take into account considerations 

such as the technological limitations of the specific source category and the control technology 
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that is feasible during startup and shutdown. Accordingly, the EPA continues to recommend the 

seven specific criteria enumerated in section III.A of the Attachment to the 1999 SSM Guidance 

as appropriate considerations for SIP provisions that establish alternative emission limitations 

that apply to startup and shutdown. The EPA repeated those criteria in the February 2013 

proposal as guidance to states for developing components of emission limitations that apply to 

sources during startup, shutdown or other specific modes of source operation to meet CAA 

requirements for SIP provisions. 

Comments received on the February 2013 proposal suggested that the purpose of the 

recommended criteria may have been misunderstood by some commenters. The criteria were 

phrased in such a way that commenters may have misinterpreted them to be criteria to be applied 

by a state retrospectively (i.e., after the fact) to an individual instance of emissions from a source 

during an SSM period, in order to establish whether the source had exceeded the applicable 

emission limitation. This was not the intended purpose of the recommended criteria at the time of 

the 1999 SSM Guidance, nor is it the intended purpose now. 

The EPA seeks to make clear in this notice that the recommended criteria are intended as 

guidance to states developing SIP provisions that include emission limitations with alternative 

emission limitations applicable to specifically defined modes of source operation such as startup 

and shutdown. A state may choose to consider these criteria in developing such a SIP provision. 

The EPA will use these criteria when evaluating whether a particular alternative emission 

limitation component of an emission limitation meets CAA requirements for SIP provisions. Any 

SIP revision establishing an alternative emission limitation that applies during startup and 

shutdown would be subject to the same procedural and substantive review requirements as any 

other SIP submission. 
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Based on comment on the February 2013 proposal, the EPA is updating the criteria to 

make clear that they are recommendations relevant for development of appropriate alternative 

emission limitations in SIP provisions. Thus, in this notice, the EPA is providing a restatement of 

its recommended criteria that reflects clarifying but not substantive changes to the text of those 

criteria. One clarifying change is removal of the word “must” from the criteria, to better convey 

that these are recommendations to states concerning how to develop an approvable SIP provision 

with alternative requirements applicable to startup and shutdown and to make clear that other 

approaches might also be consistent with the CAA in particular circumstances. 

The clarified criteria for developing and evaluating alternative emission limitations 

applicable during startup and shutdown are as follows: 

(1) The revision is limited to specific, narrowly defined source categories using specific 

control strategies (e.g., cogeneration facilities burning natural gas and using selective catalytic 

reduction); 

(2) Use of the control strategy for this source category is technically infeasible during 

startup or shutdown periods; 

(3) The alternative emission limitation requires that the frequency and duration of 

operation in startup or shutdown mode are minimized to the greatest extent practicable; 

(4) As part of its justification of the SIP revision, the state analyzes the potential worstcase emissions that could occur during startup and shutdown based on the applicable alternative 

emission limitation; 

(5) The alternative emission limitation requires that all possible steps are taken to 

minimize the impact of emissions during startup and shutdown on ambient air quality; 
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(6) The alternative emission limitation requires that, at all times, the facility is operated in 

a manner consistent with good practice for minimizing emissions and the source uses best efforts 

regarding planning, design, and operating procedures; and 

(7) The alternative emission limitation requires that the owner or operator’s actions 

during startup and shutdown periods are documented by properly signed, contemporaneous 

operating logs or other relevant evidence. 

It may be appropriate for an air agency to establish alternative emission limitations that 

apply during modes of source operation other than during startup and shutdown, but any such 

alternative emission limitations should be developed using the same criteria that the EPA 

recommends for those applicable during startup and shutdown. 

3. Response to Comments 

The EPA received a number of comments, both supportive and adverse, concerning the 

issue of how air agencies may replace existing exemptions for emissions during SSM events with 

alternative emission limitations that apply during startup, shutdown or other normal modes of 

source operation. The majority of these comments were critical of the EPA’s position but did not 

base this criticism on an interpretation of specific CAA provisions. For clarity and ease of 

discussion, the EPA is responding to these comments grouped by issue. 

a. Comments that as a technical matter sources cannot meet emission limitations (or 

cannot be accurately monitored) during startup and shutdown. 

Comment: Several commenters claimed that as a technical matter, SIP emission 

limitations cannot be met or that monitoring to ensure compliance with emission limitations 

cannot occur during startup and shutdown. Commenters raised “practical concerns” with the 

EPA’s proposal as it applies to emissions during SSM at electric generating units (EGUs). The 
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commenters claimed that it is incorrect to treat periods of startup and shutdown as part of 

“normal source operation” and claimed that it is fundamentally incorrect to characterize all 

periods of startup and shutdown as planned events. The commenters claimed that many air 

pollution control devices (APCDs) are subject to technical, operational or safety constraints that 

prevent use or optimization during startup and shutdown periods. The commenters requested the 

EPA to continue the practice of allowing states to provide “protection” from enforcement for 

excess emissions during startup and shutdown. The commenters claimed that the EPA’s premise 

for this action is that startup and shutdown events are planned and sources should be able to meet 

limits applicable during these normal operations. The commenters asserted that the proposal does 

not recognize technical and operational limits and that it conflicts with the EPA’s own 

acknowledgement in the proposal that there are sometimes technical, operational and safety 

limits that may prevent compliance with emission limitations during startup and shutdown. The 

commenters also noted that the type of equipment that a control device is attached to may affect 

the time it takes for a control device to reach optimization. Further, the commenters identified 

control technologies that cannot achieve reductions until specific temperatures are reached and 

other technologies that cannot be used during startup and/or shutdown because of technical 

limitations or safety concerns. Finally, the commenters noted that the geographical location 

and/or weather can have an effect on the operation of a source and control devices during startup 

and shutdown. 

Commenters raised specific concerns regarding pollution controls for EGUs. The 

commenters claimed that startup and shutdown events are unavoidable at EGUs even though 

they may be planned. The commenters also attached appendices providing an explanation of why 

emissions are higher for startup and shutdown for certain types of EGUs. The commenters 
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claimed that the “EPA’s proposal to eliminate the States’ SSM provisions, and prohibit them 

from adopting any provisions for startups and shutdowns, could force sources to comply with 

emission limitations during periods when they were never meant to apply, thus rendering those 

emissions limitations unachievable.” The commenters also noted that the permits for their 

sources all require that the sources minimize the magnitude and duration of emissions during 

SSM. The implication of this latter comment is that a general duty to minimize emissions is 

sufficient to justify the exemption of all emissions during SSM events in the underlying SIP 

provisions. 

Response: Although intended as criticism of the EPA’s proposed action, these comments 

in fact support the Agency’s position that states should consider startup and shutdown events as 

they promulgate standards for specific industries or even for specific sources. The commenters 

seem to suggest that because some equipment or sources cannot during startup and shutdown 

meet the emission limits that apply during “regular” operation, no limit or standards should apply 

during startup and shutdown. The EPA disagrees. As the court in Sierra Club held, emission 

limitations must apply at “all times.” That is not to say that the emission limitation must impose 

the same numerical limitation or impose the same other control requirement at all times. As 

explained at length in section VII.A of this document, the EPA interprets the CAA to allow SIP 

emission limitations that may be a combination of numerical limitations, technological control 

measures and/or work practice requirements, so long as the resulting emission limitations are 

properly developed to meet CAA requirements and are legally and practically enforceable. As 

the commenters noted, the EPA does recognize that some control equipment cannot be operated 

at all or in the same manner during every mode of normal operations. 
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In its 1999 SSM Guidance, the EPA expressly recognized that an appropriate way to for a 

state to address such technological limitations is to set alternative emission limitations that apply 

during periods of startup and shutdown as part of the SIP emission limitation.238 In these cases 

the state should consider how the control equipment works in determining what standards should 

apply during startup and shutdown. In addition, as noted by commenters, such standards may 

vary based on location (e.g., standards in a hot and humid area may differ from those adopted for 

a cool and dry area). Some equipment during startup and shutdown may be unable to meet the 

same emission limitation that applies during steady-state operations and so alternative limitations 

for startup and shutdown may be appropriate.239 However, for many sources, it should be 

feasible to meet the same emission limitation that applies during steady-state operations also 

during startup and shutdown.240 These are issues for the state to consider in developing specific 

regulations as they revise the deficient SIP provisions identified in this action. The EPA 

emphasizes that the state has discretion to determine the best means by which to revise a 

deficient provision to eliminate an automatic or discretionary SSM exemption, so long as that 

revision is consistent with CAA requirements. The EPA will work with the states as they 

consider possible revisions to deficient provisions. 

 

238 See 1999 SSM Guidance, Attachment at 4–5. 

239 The EPA notes that it has taken this approach in its own recent actions establishing emission 

limitations for sources. See, e.g., “National Emission Standards for Hazardous Air Pollutants for 

Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters; Final rule; 

notice of final action on reconsideration,” 78 FR 7137 (January 31, 2013) (example of work 

practice requirement for startup as a component of a continuous emission limitation). 

240 The EPA notes that it has taken this approach in its own recent actions establishing emission 

limitations for sources. See, e.g., “National Emission Standards for Hazardous Air Pollutants 

Residual Risk and Technology Review for Flexible Polyurethane Foam Production; Final rule,” 

79 FR 48073 (August 15, 2014) (example of NESHAP emission limitation that is continuous and 

does not include a different component for periods of startup or shutdown). 
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The EPA recognizes that a malfunction may cause a source to shut down in a manner 

different than in a planned shutdown, and in that case, such a shutdown would typically be 

considered part of the malfunction event. However, as part of the normal operation of a facility, 

sources typically will also have periodic or otherwise scheduled startup and shutdown of 

equipment, and steps to limit emissions during this type of event are or can be planned for. The 

EPA disagrees with the suggestion of commenters that because some startup or shutdown events 

may be unplanned, all startup and shutdown events should be exempt from compliance with any 

requirements. For those events that are planned, the state should be able to establish requirements 

to regulate emissions, such as a numerical limitation, technological control measure or work 

practice standard that will apply as a part of the revised emission limitation. For unplanned 

events that are part of a malfunctions, they should be treated the same as a malfunction; however, 

as with malfunctions, startup and shutdown events cannot be exempted from compliance with 

SIP requirements. Questions of liability and remedy for violations that result from malfunctions 

are to be resolved in the context of an enforcement action, if such an action occurs. 

b. Comments that it is impossible, unreasonable or impractical for states to develop 

emission limitations that apply during startup and shutdown instead of existing exemptions. 

Comment: A number of commenters suggested that it will be difficult for states to 

develop emission limits that apply during startup and shutdown. One state commenter reasoned 

that alternative emission limits are applied to facilities in that state through individual permits on 

a case-by-case basis and claimed that there are 500 permitted facilities in the state. The 

commenter contended that “non-steady-state” limits would need to be set for startup and 

shutdown for all 500 permitted facilities and that such an effort would be “time, resource, and 

data intensive.” The state commenter further contended that it would be unreasonable to require 
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the state to include such limits “for every source” in the SIP because “permit modifications 

would need to occur every time there is a new emission source, a source ceases to operate, or an 

emission-related regulation is changed.” 

A local government commenter stated that establishing limits for startup and shutdown 

while still demonstrating compliance with the NSR regulations (including protection of the 

NAAQS and PSD increments and maintenance of BACT or LAER) would be a difficult, timeconsuming task that was mostly impractical. 

An industry commenter claimed that the EPA is encouraging states to adopt a numerical 

alternative emission limit that would apply during startup and shutdown. The commenter 

claimed that adequate and accurate emissions data are necessary to do so and that such 

information is not generally available for existing equipment or, in many cases, for new 

equipment. Furthermore, the commenter asserted, even if an emission limit could be established 

for startup and shutdown, there are no current approved test measures to verify compliance 

during such modes of operation. Even where data are available, the commenter alleged, the data 

may not be representative of actual conditions because of limitations related to low-load 

conditions. If a state lacks information to conclude that a limit can be met, the commenter 

argued, the state should not be required to establish numerical limits but should instead be 

allowed “to specify that numerical standards do not apply to those conditions or that those 

conditions are exempt, or should be allowed to establish work practice standards.” 

Response: The comments of the state commenter seem to be based on the premise that all 

sources will be unable to meet otherwise applicable SIP emission limitations during periods of 

startup and shutdown. The EPA anticipates that many types of sources should be able during 

startup and shutdown to meet the same emission limitation that applies during full operation. 
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Additionally, even where a specific type of operation may not during startup and/or shutdown be 

able to meet an emission limitation that applies during full operation, the state should be able to 

develop appropriate limitations that would apply to those types of operations at all similar types 

of facilities. The EPA believes that there will be limited, if any, cases where it may be necessary 

to develop source-specific emission requirements for startup and/or shutdown. In any event, this 

is a question that is best addressed by each state in the context of the revisions to the SIP 

provisions at issue in this action. To the extent that there are appropriate reasons to establish an 

emission limitation with alternative numerical, technological control and/or work practice 

requirements during startup or shutdown for certain categories of sources, this SIP call action 

provides the state with the opportunity to do so. 

As to the commenter’s concern that such alternative emission limitations should not be 

included in a state’s SIP, the EPA disagrees. The SIP needs to reflect the control obligations of 

sources, and any revision or modification of those obligations should not be occurring through a 

separate process, such as a permit process, which would not ensure that “alternative” compliance 

options do not weaken the SIP. The SIP is a combination of state statutes, regulations and other 

requirements that the EPA approves for demonstrating attainment and maintenance of the 

NAAQS, protection of PSD increments, improvement of visibility and compliance with other 

CAA requirements. As discussed in section X.B of this document, any revisions to obligations in 

the SIP need to occur through the SIP revision process and must comply with sections 110(k)(3), 

110(l) and 193 and any other applicable substantive requirements of the CAA. 

As to concerns that a SIP revision will be necessary every time a new source comes into 

existence, an existing source is permanently retired or a new regulation is promulgated, the EPA 

does not see these as significant concerns. Unless the startup or shutdown process for an 
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individual source is truly unique to that source, then existing SIP provisions for sources within 

the same industrial category should be able to apply to any new source. Moreover, assuming any 

new source is subject to permitting obligations, then any applicable startup and shutdown issues 

should already be resolved in developing the permit for such source. The state could choose to 

incorporate that permit by reference into the SIP at the time it next modifies its SIP. Further, 

assuming that there is a source-specific regulation for a source in the SIP (a circumstance that the 

EPA believes would occur only rarely), the state is not obligated to remove such provision when 

the source is retired. Rather, the state could leave the provision in its rules or remove such a 

provision the next time it submits another SIP revision or when it chooses to do a “cleanup” of 

the SIP, an activity that numerous states have taken from time to time. Finally, whenever a new 

regulation is promulgated is precisely the time that a state should be considering the appropriate 

provisions that would apply during startup and shutdown, as that is the time when the state is 

considering what is necessary to comply with the CAA and what is necessary to meet attainment, 

maintenance or other requirements of the CAA. 

The local government commenter contended that establishing limits for startup and 

shutdown while still demonstrating compliance with the NSR regulations (including protection 

of the NAAQS and PSD increments and imposition of BACT or LAER level controls) would be 

a difficult, time-consuming task that was impractical. The commenter does not explain why this 

is so. The implication is that a SIP provision that provides an exemption or an affirmative 

defense for emissions during startup and shutdown would be compliant with the statutory 

requirements and NSR regulations (including attainment of the NAAQS and protecting PSD 

increments) while it would be difficult to formulate a SIP provision that regulated such emissions 

that would be compliant. The suggestion that a SIP provision that does not regulate emissions 
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during startup and shutdown would be more likely to address NAAQS attainment and to protect 

PSD increments than would a SIP provision that does regulate such emissions is simply illogical. 

The EPA further notes that the Agency’s interpretation of the CAA, explicitly set forth in a 1993 

guidance document, has been that periods of startup and shutdown must be addressed in any new 

source permit.241 Moreover, the EPA explained in the February 2013 proposal, in the SNPR and 

in the background memorandum accompanying the February 2013 proposal concerning the legal 

basis for this action why exemptions and affirmative defenses applicable to emissions during 

SSM events are not consistent with CAA requirements for SIP provisions. 

c. Comments that the EPA should “authorize” states to replace SSM exemptions 

with “work practice” standards developed by the EPA in its own recent NESHAP and NSPS 

rules. 

Comment: Commenters suggested that the EPA should allow states to use work practice 

standards to address emissions during startup and shutdown. The NESHAP rules cited by 

commenters included the Industrial Boiler MACT rule242 and the MATS rule, and the NSPS 

rules cited by the commenters included the NSPS for Electric Utility Steam Generating Units (40 

CFR part 60, subpart Da) and the gas turbine NSPS as examples of where the EPA itself has 

established work practice standards rather than numerical emission limitations for periods of 

startup and shutdown. The commenters suggested that where these work practice standards are 

already in place, states should be able to rely on the work practice standards rather than having to 

create new SIP provisions. 

 

241 See Memorandum from John B. Rasnic, EPA/OAQPS, January 28, 1993, in the rulemaking 

docket at EPA-HQ-OAR-2012-0322-0022. 

242 The Industrial Boiler MACT rule regulates industrial, commercial and institutional boilers 

and process heaters at major sources under 40 CFR part 63, subpart DDDDD. 
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Response: The EPA agrees that states are not precluded from adopting work practice 

standards to address periods of startup and shutdown as a component of a SIP emission 

limitation that applies continuously. Such work practice standards must meet the otherwise 

applicable CAA requirements (e.g., be a RACT-level control for the source as part of an 

attainment plan requirement) and the necessary parameters to make it legally and practically 

enforceable (e.g., have adequate recordkeeping, reporting and/or monitoring requirements to 

assure compliance). However, it cannot automatically be assumed that emission limitation 

requirements in recent NESHAP and NSPS are appropriate for all sources regulated by SIPs. The 

universe of sources regulated under the federal NSPS and NESHAP programs is not identical to 

the universe of sources regulated by states for purposes of the NAAQS. Moreover, the pollutants 

regulated under the NESHAP (i.e., hazardous air pollutants) are in many cases different than 

those that would be regulated for purposes of attaining and maintaining the NAAQS, protecting 

PSD increments, improving visibility and meeting other CAA requirements.243 Thus, the EPA 

cannot say as a matter of law that those federal regulations establish appropriate emission 

limitation requirements for all of the sources that states are regulating in their SIPs or for the 

purpose for which they are being regulated. The EPA believes, however, that those federal 

regulations and the technical materials in the public record for those rules may provide assistance 

for states as they develop and consider regulations for sources in their states and may be 

appropriate for adoption by the state in certain circumstances. In particular, the NSPS regulations 

should provide very relevant information for sources of the same type, size and control 

 

243 While some hazardous pollutants are also VOCs or particulate matter, many HAP are not. 

Moreover, there are many VOCs and types of particulate matter that are not HAP and thus are 

not regulated under the MACT standards. MACT standards also do not address other criteria 

pollutants or pollutant precursors from sources that may be relevant for SIP purposes. 
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equipment type, even if the sources were not constructed or modified within a date range that 

would make them subject to the NSPS. The EPA therefore encourages states to explore these 

approaches, as well as any other relevant information available, in determining what is 

appropriate for revised SIP provisions. 

d. Comments that if states remove existing SSM exemptions and replace them with 

alternative emission limitations that apply during startup and shutdown events, this would 

automatically be consistent with the requirements of CAA section 193. 

Comment: Commenters stated that section 193 was included in the CAA to prohibit states 

from modifying regulations in place prior to November 15, 1990, unless the modification ensures 

equivalent or greater reductions of the pollutant. The commenters asserted that to the extent a 

state replaces “general excess emissions exclusions and/or affirmative defense provisions” such 

amendments would per se be more stringent than the provisions they replace. The commenters 

also contended that any replacement SIP provision that spells out more clearly how a source will 

operate ensures equivalent or greater emission reductions. The commenters urged the EPA to 

clarify that any revisions pursuant to a final SIP call would not be considered “backsliding.” 

Response: The EPA agrees with the commenters that any SIP submission made by a state 

in response to this SIP call action will need to comply with the requirements of section 193 of the 

CAA, if that section applies to the SIP provision at issue. In addition, such SIP provision will 

also need to comply with section 110(l), which requires that SIP revisions do not interfere with 

attainment, reasonable progress or any other applicable requirement of the CAA. However, it is 

premature to draw the conclusion that any SIP revision made by a state in response to this SIP 

call will automatically meet the requirements of section 110(l) and section 193. Such a 

conclusion could only be made in the context of reviewing the actual SIP revision. The EPA will 
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address this issue, for each SIP revision in response to this SIP call action, at the time that it 

proposes and finalizes action on the SIP revision, and any comments on this issue can be raised 

during those individual rulemaking actions. The EPA provides additional guidance to states on 

the analysis needed to comply with section 110(l) and section 193 in section X.B of this notice. 

C. Director’s Discretion Provisions Pertaining to SSM Events 

1. What the EPA Proposed 

In the February 2013 proposal, the EPA stated and explained in detail the reasons for its 

belief that the CAA prohibits unbounded director’s discretion provisions in SIPs, including those 

provisions that purport to authorize unilateral revisions to, or exemptions from, SIP emission 

limitations for emissions during SSM events.244 

2. What is Being Finalized in This Action 

The EPA is reiterating its interpretation of the CAA with respect to unbounded director’s 

discretion provisions applicable to emissions during SSM events, which is that SIP provisions 

cannot contain director’s discretion to alter SIP requirements, including those that allow for 

variances or outright exemptions for emissions during SSM events. This interpretation has been 

clear with respect to emissions during SSM events in the SSM Policy since at least 1999. In the 

1999 SSM Guidance, the EPA stated that it would not approve SIP revisions “that would enable 

a State director’s decision to bar EPA’s or citizens’ ability to enforce applicable 

requirements.”245 Director’s discretion provisions operate to allow air agency personnel to make 

just such unilateral decisions on an ad hoc basis, up to and including the granting of complete 

exemptions for emissions during SSM events, thereby negating any possibility of enforcement 

 

244 See February 2013 proposal, 78 FR 12459 at 12485–86. 

245 See 1999 SSM Guidance at 3. 
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for what would be violations of the otherwise applicable emission limitation. Given that the EPA 

interprets the CAA to bar exemptions from SIP emission limitations for emissions during SSM 

events in the first instance, the fact that director’s discretion provisions operate to authorize these 

exemptions on an ad hoc basis compounds the problem. The EPA acknowledges, however, that 

both states and the Agency have, in some instances, failed to adhere to the requirements of the 

CAA with respect to this issue consistently in the past, and thus the need for this SIP call to 

correct existing deficiencies in SIPs.246 In order to be clear about its interpretation of the CAA 

with respect to this point on a going-forward basis, the EPA is reiterating in this action that SIP 

provisions cannot contain unbounded director’s discretion provisions, including those that 

operate to allow for variances or outright exemptions from SIP emission limitations for excess 

emissions during SSM events. 

Many commenters on the February 2013 proposal opposed the EPA’s interpretation of 

the CAA with respect to director’s discretion provisions simply on the grounds that states are per 

se entitled to have unfettered discretion with respect to the content of their SIP provisions. Other 

commenters argued that any director’s discretion provision is merely a manifestation of an air 

agency’s general “enforcement discretion.” Some commenters simply asserted that recent court 

decisions by the Fifth Circuit definitively establish that the CAA does not prohibit SIP provisions 

 

246 In this action, the EPA is addressing the specific SIP provisions with director’s discretion 

provisions that the Petitioner listed in the Petition. In the event that there are other such 

impermissible director’s discretion provisions in existing SIPs, the EPA will address those 

provisions in a later action. 
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that include director’s discretion, regardless of whether those provisions contain any limitations 

whatsoever on the exercise of that discretion.247 The commenters did not, however, address the 

specific statutory interpretations that the EPA set forth in the February 2013 proposal to explain 

why SIP provisions that authorize unlimited director’s discretion are prohibited by CAA 

provisions applicable to SIP revisions. 

As explained in detail in the February 2013 proposal and in section VII.C of this notice, 

the EPA interprets the CAA to prohibit SIP provisions that include unlimited director’s 

discretion to alter the SIP emission limitations applicable to sources, including those that operate 

to allow exemptions for emissions from sources during SSM events. The EPA believes that such 

provisions that operate to authorize total exemptions from emission limitations on an ad hoc

basis are especially problematic. Given that the EPA interprets section 110(a)(2)(A) and section 

302(k) to preclude exemptions for emissions during SSM events in emission limitations in the 

first instance, it is also impermissible for states to have SIP provisions that authorize such 

exemptions on an ad hoc basis. These provisions functionally allow the air agency to impose its 

own enforcement discretion decisions on the EPA and other parties by granting exemptions for 

emissions that should be treated as violations of the applicable SIP emission limitations. 

Provisions that functionally allow such exemptions are also inconsistent with requirements of the 

CAA related to enforcement including: (i) the general requirements of section 110(a)(1) that 

SIPs provide for enforcement; (ii) the section 110(a)(2)(A) requirement that the specific emission 

 

247 For example, commenters on the February 2013 proposal cited two decisions of the Fifth 

Circuit within which the court cited a prior EPA approval of a SIP revision in Georgia that 

contained director’s discretion provisions supposedly comparable to those at issue in the Fifth 

Circuit cases. These provisions were not included in the Petition and the EPA is not reexamining 

those provisions as part of this action. 
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limitations and other contents of SIPs be enforceable; and (iii) the section 110(a)(2)(C) 

requirement that SIPs contain a program to provide for enforcement. Moreover, these provisions 

operate to interfere with the enforcement structure of the CAA provided in section 113 and 

section 304, through which the EPA and other parties have authority to seek enforcement for 

violations of CAA requirements, including SIP emission limitations. 

There are two ways in which such a provision can be consistent with CAA requirements: 

(1) when the exercise of director’s discretion by the state agency to alter or eliminate the SIP 

emission limitation can have no effect for purposes of federal law unless and until the EPA 

ratifies that state action with a SIP revision; or (2) when the director’s discretion authority is 

adequately bounded such that the EPA can ascertain in advance, at the time of approving the SIP 

provision, how the exercise of that discretion to alter the SIP emission limitations for a source 

could affect compliance with other CAA requirements. If the provision includes director’s 

discretion that could result in violation of any other CAA requirement for SIPs, then the EPA 

cannot approve the provision consistent with the requirements of section 110(k)(3) and section 

110(l). For example, a director’s discretion provision that authorizes state personnel to excuse 

source compliance with SIP emission limitations during SSM events could not be approved 

because the provision would run afoul of the requirement that sources be subject to emission 

limitations that apply continuously, consistent with section 302(k).

3. Response to Comments 

The EPA received a number of comments, both supportive and adverse, concerning the 

issue of director’s discretion provisions in SIPs. The majority of these comments were critical of 

the EPA’s position but did not base this criticism on an interpretation of specific CAA 
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provisions. For clarity and ease of discussion, the EPA is responding to these comments grouped 

by issue. 

a. Comments that broad state discretion to develop SIP provisions includes the 

authority to create provisions that include director’s discretion variances or exemptions for 

excess emission during SSM events. 

Comment: A number of state and industry commenters argued that because states have 

great discretion when developing SIP provisions in general, this necessarily includes the ability 

to create director’s discretion provisions in SIPs that authorize state personnel to grant unilateral 

variances or exemptions for emissions during SSM events. According to commenters, the 

overarching principle of “cooperative federalism” and court decisions concerning the division of 

regulatory responsibilities between the states and the EPA support their view that states can 

create SIP provisions that provide authority to alter the SIP emission limitations or other 

requirements via director’s discretion provisions without restriction. 

Response: The EPA disagrees with the commenters’ view that director’s discretion 

provisions in SIPs are per se permissible because of the principles of cooperative federalism. As 

explained in more detail in section V.D.2 of this document, states and the EPA each have 

authorities and responsibilities under the CAA. With respect to SIPs, under section 107(a) the 

states have primary responsibility for assuring attainment of the NAAQS within their borders. 

Under section 110(a) the states have a statutory duty to develop and submit a SIP that provides 

for the attainment, maintenance and enforcement of the NAAQS, as well as meeting many other 

CAA requirements and objectives. The specific procedural and substantive requirements that 

states must meet for SIPs are set forth in section 110(a)(1) and section 110(a)(2) and in other 

more specific requirements throughout the CAA (e.g., the attainment plan requirements for each 
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of the NAAQS as specified in part D). By contrast, the EPA has its own statutory authorities and 

responsibilities, including the obligation to review new SIP submissions for compliance with 

CAA procedural and substantive requirements pursuant to sections 110(k)(3), 110(l) and 193. In 

addition, the EPA has authority to assure that previously approved SIP provisions continue to 

meet CAA requirements, whether through the SIP call authority of section 110(k)(5) or the error 

correction authority of section 110(k)(6). 

As the EPA explained in detail in the February 2013 proposal, SIP provisions that include 

unbounded director’s discretion to alter the otherwise applicable emission limitations are 

inconsistent with CAA requirements. Such provisions purport to authorize air agency personnel 

unilaterally to change or to eliminate the applicable SIP emission limitations for a source without 

meeting the requirements for a SIP revision. Pursuant to the EPA’s own responsibilities under 

sections 110(k)(3), 110(l) and 193 and any other CAA provision substantively germane to the 

specific SIP provision at issue, it would be inappropriate for the Agency to approve a SIP 

provision that automatically preauthorized the state unilaterally to revise the SIP emission 

limitation without meeting the applicable procedural and substantive statutory requirements for a 

SIP revision. Section 110(i) prohibits modification of SIP requirements for stationary sources by 

either the state or the EPA, except through specified processes. The EPA’s implementing 

regulations applicable to SIP provisions likewise impose requirements for a specific process for 

the approval of SIP revisions.248 In addition, section 116 explicitly prohibits a state from 

adopting or enforcing regulations for sources that are less stringent than what is required by the 

emission limitations in its SIP, i.e., the emission limitation previously approved by the EPA as 

 

248 See, e.g., 40 CFR 51.104(d) and 40 CFR 51.105. 
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meeting the requirements of the CAA applicable to that specific SIP provision. It is a 

fundamental tenet of the CAA that states cannot unilaterally change SIP provisions, including the 

emission limitations within SIP provisions, without the EPA’s approval of the change through 

the appropriate process. This core principle has been recognized by multiple courts.249 

b. Comments that director’s discretion provisions are an exercise of “enforcement 

discretion.” 

Comment: Several state and industry commenters asserted that the EPA was wrong to 

interpret the CAA to preclude director’s discretion provisions, because such provisions are 

merely an exercise of a state’s traditional “enforcement discretion.” 

Response: The EPA disagrees that a director’s discretion provision in a SIP is a valid 

exercise of enforcement discretion. Normally, the concept of enforcement discretion is 

understood to mean that a regulator has discretion to determine whether a specific violation of 

the law by a source warrants enforcement and to determine the nature of the remedy to seek for 

any such violation. The EPA of course agrees that states have enforcement discretion of this type 

and that the states may exercise such enforcement discretion as they see fit, as does the Agency 

 

249 See, e.g., Sierra Club, et al. v. TVA, 430 F.3d 1337, 1346 (11th Cir. 2005) (“If a state wants to 

add, delete, or otherwise modify a SIP provision, it must submit the proposed change to EPA for 

approval”); Duquesne Light Co. v. EPA, 698 F.2d 456, 468 n.12 (D.C. Cir. 1983) (“with certain 

enumerated exceptions, states do not have the power to take any action modifying any 

requirement of their SIPs, without approval from EPA”); Train v. NRDC, 421 U.S. 60, 92 (1975) 

(“[A] polluter is subject to existing requirements until such time as he obtains a variance, and 

variances are not available under the revision authority until they have been approved by both 

the State and the Agency”). 
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itself. However, the EPA does not agree that air agencies may create SIP provisions that operate 

to eliminate the ability of the EPA or citizens to enforce the emission limitations of the SIP. The 

EPA stated clearly in the 1999 SSM Guidance that it would not approve SIP provisions that 

“would enable a State director’s decision to bar EPA’s or citizens’ ability to enforce applicable 

requirements.”250 The Agency explained at that time that such an approach is inconsistent with 

the requirements of the CAA applicable to the enforcement of SIPs. 

The commenters’ argument was that states may create SIP provisions through which they 

may unilaterally decide that the emissions from a source during an SSM event should be 

exempted, such that the emissions cannot be treated as a violation by anyone. A common 

formulation of such a provision provides only that the source needs to notify the state regulatory 

agency that an exceedance of the emission limitations occurred and to report that the emissions 

were the result of an SSM event. If those minimal steps occur, then such provisions commonly 

authorize state personnel to make an administrative decision that the emissions in question were 

not a “violation” of the applicable emission limitation. It may be entirely appropriate for the state 

agency to elect not to bring an enforcement action based on the facts and circumstances of a 

given SSM event, as a legitimate exercise of its own enforcement discretion. However, by 

creating a SIP provision that in effect authorizes the state agency to alter or suspend the 

otherwise applicable SIP emission limitations unilaterally through the granting of exemptions, 

the state agency would functionally be revising the SIP with respect to the emission limitations 

on the source. This revision of the applicable emission limitation would have occurred without 

satisfying the requirements of the CAA for a SIP revision. As a result of this ad hoc revision of 

 

250 1999 SSM Guidance at 3. 
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the SIP emission limitation, the EPA and other parties would be denied the ability to exercise 

their own enforcement discretion. This is contrary to the fundamental enforcement structure of 

the CAA, as provided in section 113 and section 304, through which the EPA and other parties 

are authorized to bring enforcement actions for violations of SIP emission limitations. The state’s 

decision not to exercise its own enforcement discretion cannot be a basis on which to eliminate 

the legal rights of the EPA and other parties to seek to enforce. 

The commenters also suggested that the director’s discretion provisions authorizing 

exemptions for SSM events are nonsegregable parts of the emission limitations, i.e., that states 

have established the numerical limitations at overly stringent levels specifically in reliance on the 

existence of exemptions for any emissions during SSM events. Although commenters did not 

provide facts to support the claims that states set more stringent emission limitations in reliance 

on SSM exemptions, in general or with respect to any specific emission limitation, the EPA 

acknowledges that this could possibly have been the case in some instances. Even if a state had 

taken this approach, however, it does not follow that SIP provisions containing exemptions for 

SSM events are legally permissible. Emission limitations in SIPs must be continuous. When a 

state takes action in response to this SIP call to eliminate the director’s discretion provisions or 

otherwise to revise them, the state may elect to overhaul the emission limitation entirely in order 

to address this concern. So long as the resulting revised SIP emission limitation is continuous 

and meets the requirements of sections 110(k)(3), 110(l) and 193 and any other sections that are 

germane to the type of SIP provision at issue, the state has discretion to revise the provision as it 

determines best. 
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c. Comments that the EPA’s having previously approved a SIP provision that 

authorizes the granting of variances or exemptions for SSM events through the exercise of 

director’s discretion renders the provision consistent with CAA requirements. 

Comment: Several state and industry commenters argued that the EPA’s past approval of 

a SIP provision with a director’s discretion feature automatically means that the exercise of that 

authority (whether to revise the applicable SIP emission limitations unilaterally or to grant ad 

hoc exemptions from SIP emission limitations) is valid under the CAA. One commenter asserted 

that because the EPA has previously approved such a provision, “that discretion is itself part of 

the SIP, and the exercise of discretion in no way modifies SIP requirements.” Another 

commenter argued that director’s discretion provisions in SIPs are per se valid because “[a]ll of 

the SIP provisions went through a public procedure at the time of their initial SIP approval.” 

Response: First, the EPA disagrees with the theory that a SIP provision that includes 

director’s discretion authority for state personnel to modify or grant exemptions from SIP 

emission limitations unilaterally is valid merely by virtue of the fact that the Agency previously 

approved it. By definition, when the EPA makes a finding of substantial inadequacy and issues a 

SIP call, that signifies that the Agency previously approved a SIP provision that does not meet 

CAA requirements, whether that deficiency existed at the time of the original approval or arose 

later. The EPA has explicit authority under section 110(k)(5) to require that a state eliminate or 

revise a SIP provision that the Agency previously approved, whenever the EPA finds an existing 

SIP provision to be substantially inadequate to meet CAA requirements. The fact that the EPA 

previously approved it does not mean that a deficient provision may remain in the SIP forever 

once the Agency determines that it is deficient. 
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Second, the EPA disagrees that the fact that a SIP provision underwent public process at 

the time of its original creation by the state, or at the time of its approval by EPA as part of the 

SIP, means per se that the provision is consistent with CAA requirements. If an existing SIP 

provision is deficient because it in effect allows a state to revise existing SIP emission limitations 

without meeting the many explicit statutory requirements for a SIP revision, the fact that the 

revision that created the impermissible provision itself met the proper procedural requirements 

for a SIP revision is irrelevant. Even perfect compliance with the procedural requirements for a 

SIP revision at the time of its development by the state or its approval by the EPA does not 

override a substantive deficiency in the provision, nor does it preclude the later issuance of a SIP 

call to correct a substantive deficiency. 

Third, the EPA disagrees with the circular logic that because a deficient provision with 

director’s discretion currently exists in a SIP, it means that exercise of the director’s discretion to 

grant variances or outright exemptions to sources for emissions during SSM events is therefore 

consistent with CAA requirements for SIPs. An unbounded director’s discretion provision that 

authorizes an air agency to alter or eliminate the otherwise applicable SIP emission limitation 

functionally allows the state to revise the SIP emission limitation without meeting the 

requirements for a SIP revision. In particular, when such provisions authorize state personnel to 

grant outright exemptions from the SIP emission limitations, this is tantamount to a revision of 

the SIP emission limitation without complying with the procedural and substantive requirements 

of the CAA applicable to SIP revisions, including section 110(l), section 193 and any other 

substantive requirements applicable to the particular SIP emission limitation in question. 

d. Comments that director’s discretion provisions in SIPs are not prohibited by the 

CAA, based on recent judicial decisions. 
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Comment: A number of state and industry commenters argued that nothing in the CAA 

explicitly prohibits states from having SIP provisions that include director’s discretion 

authorization for state personnel to modify or eliminate existing SIP provisions unilaterally, with 

or without any process or within any limiting parameters. In support of this proposition, the 

commenters cited recent decisions of the Fifth Circuit in two cases concerning the EPA’s 

disapproval of SIP submissions from the state of Texas. Commenters argued that the EPA’s 

interpretation of the CAA to prohibit director’s discretion provisions in SIPs is incorrect in light 

of the decision of the court in Texas v. EPA.

251 According to commenters, the court’s decision 

establishes that no provision of the CAA bars such provisions. To support this contention, one 

commenter quoted the court’s decision extensively, highlighting the statement, “...the EPA has 

invoked the term ‘director discretion’ as if that term were an independent and authoritative 

standard, and has not linked the term to the language of the CAA.” Similarly, the commenters 

cited another decision of that court in Luminant Generation Co. v. EPA.

252 From that decision, 

commenters quoted the court’s statement that the “EPA had no legal basis to demand ‘replicable’ 

limitations on the Director’s discretion” and the succeeding sentence, “[n]ot once in its proposed 

or final disapproval, or in its argument before this court, has the EPA pointed to any applicable 

provision of the Act or its regulations that includes a ‘replicability’ standard.” These commenters 

did not, however, address the specific statutory provisions identified by the EPA in the February 

2013 proposal and the explanation that the Agency provided with respect to this issue. 

Response: The EPA disagrees that either decision cited by commenters stands for the 

definitive proposition they assert, i.e., that director’s discretion provisions in SIPs are not 

 

251 690 F.3d 670 (5th Cir. 2012). 

252 675 F.3d 917 (5th Cir. 2012). 
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precluded by the CAA. In Luminant Generation Co. v. EPA, the court evaluated the EPA’s 

disapproval of a SIP submission from the state of Texas that created SIP provisions to implement 

minor source permitting requirements. The EPA disapproved the SIP submission for several 

reasons, one of which was based on the director’s discretion provision prohibiting use of the 

standard permit for a pollution control project that the director determines raises health concerns 

or threatens the NAAQS. The EPA was concerned that this provision gave the director of the 

state agency discretion to make case-by-case decisions about what the specific permit terms 

would be for each source, without sufficient parameters or limitations on the exercise of that 

authority. Thus, the EPA reasoned that without any boundaries on the exercise of this authority 

for director’s discretion, it would be impossible for the Agency to know in advance (i.e., at the 

time of acting on the SIP submission) whether the state agency would only use that discretion in 

a way that would result in permits with terms consistent with meeting CAA requirements.253 As 

the EPA explained in the rulemaking at issue in the Luminant Generation v. EPA case, “[t]here 

are no replicable conditions in the PCP Standard Permit that specify how the [TCEQ] Director’s 

 

253 The EPA notes that the Luminant court focused on the fact that the director’s discretion 

provision included the discretion to require more of sources, if there “are health effects concerns 

or the potential to exceed the [NAAQS],” and the court expressed that it did not understand why 

that requirement was not alone adequate to allay the Agency’s concerns. Luminant, 675 F.3d 

917, 929 n.11. The EPA’s primary concern, although not clearly articulated in the rulemaking 

record, was that at the time of acting on the SIP submission, there was no way for the Agency to 

know in advance what the state would require of any source in the first instance, let alone what 

additional things the state might require in situations where it unilaterally decided that more 

might be necessary in any given permit. 
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discretion is to be implemented” for the individual case-by-case determinations.254 In other 

words, the EPA was being asked to approve a SIP provision without knowing how the SIP 

provision would actually be implemented and thus without knowing whether the results would 

be consistent with applicable CAA requirements. 

As the commenters stated, the Luminant court vacated the EPA’s disapproval of the SIP 

submission for several reasons, including the rejection of the Agency’s argument that it could not 

approve the SIP submission due to the director’s discretion feature of the SIP provisions and the 

resulting lack of “replicability.”255 The court found that the EPA “failed to identify a single 

provision of the Act that Texas’s program violated, let alone explain its reasons for reaching its 

conclusion.”256 With respect to the directors’ discretion issue, phrased in terms of “replicability,” 

the court found that “[n]ot once in its proposed or final disapproval, or in its argument before this 

 

254 See “Approval and Promulgation of Implementation Plans; Texas; Revisions to the New 

Source Review (NSR) State Implementation Plan (SIP); Prevention of Significant Deterioration 

(PSD), Nonattainment NSR (NNSR) for the 1997 8-Hour Ozone Standard, NSR Reform, and a 

Standard Permit; Proposed rule,” 74 FR 48467 at 48476 (September 23, 2009). 

255 The term “replicable” was taken from EPA guidance concerning SIP provisions for 

attainment plans. As a “fundamental principle” for SIP provisions and permits, the EPA 

explained that the requirements imposed upon sources should be “replicable”; i.e., if they contain 

“procedures for changing the rule, interpreting the rule, or determining compliance with the rule, 

the procedures are sufficiently specific and nonsubjective so that two independent entities 

applying the same procedures would obtain the same result.” See General Preamble, 57 FR 

13498 at 13568 (April 16, 1992). The EPA’s intent in using this term, although not clearly 

expressed in the rulemaking record, has been to indicate that a properly constructed SIP 

provision with an appropriate degree of discretion and flexibility would contain sufficient 

specifications and limits on the exercise of that discretion such that the Agency could adequately 

evaluate the provision at the time of its submission. Absent sufficient limits on the discretion, the 

EPA could not properly evaluate how exercise of the discretion could affect compliance with 

CAA requirements. 

256 Luminant, 675 F.3d 917, 924 (5th Cir. 2012). 
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court, has the EPA pointed to any applicable provision of the Act or its regulations that include a 

‘replicability’ standard.” 

The EPA believes that the Luminant court’s decision is distinguishable on several 

important grounds. Most importantly, the court rejected the EPA’s disapproval of the SIP 

submission because the Agency had not provided an adequate explanation of why the director’s 

discretion provision at issue was inconsistent with the requirements of the CAA for SIP 

provisions. The Luminant court emphasized the absence of any explanation in the administrative 

record for the proposed or final actions that explained which specific provisions of the CAA 

preclude such a provision and why. In the February 2013 proposal and in this notice, the EPA 

has identified and explained the specific CAA provisions that operate to preclude unbounded 

director’s discretion provisions in SIPs. 

Second, the Luminant court based its decision in part on the view that the specific 

director’s discretion provision at issue in that case would always result in more stringent 

regulation of affected sources and always entail exercise of the discretion in a way that would 

protect the NAAQS.257 Although its view was not articulated clearly in the record, the EPA did 

not agree with that assessment because it was not possible to evaluate in advance how the 

director’s discretion authority would in fact be exercised. By contrast, the SIP provisions at issue 

in this action are not structured in such a way as to allow the exercise of discretion only to make 

the emission limitations more stringent. To the contrary, the director’s discretion provisions at 

issue in this action authorize the state agencies to excuse sources from compliance with the 

 

257 Luminant, 675 F.3d 917, 929 n.11 (“The provision at issues states: “This standard permit 

must not be used [if] the executive director determines there are health effects concerns or the 

potential to exceed a [NAAQS] . . . until those concerns are addressed to the satisfaction of the 

executive director.”). 
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otherwise applicable SIP emission limitation during SSM events. Were the sources seeking these 

discretionary exemptions meeting the applicable SIP emission limitations, they would not need 

an exemption. It logically follows that sources are seeking these exemptions because their 

emissions during such events are higher than the otherwise applicable emission limitation allows. 

Unlike the specific director’s discretion provision at issue in the Luminant Generation v. EPA 

case, which the court said “can only serve to protect the NAAQS,” the exercise of the director’s 

discretion authority in the SIP provisions at issue in this action can operate to make the emission 

limitations less stringent and can thereby undermine attainment and maintenance of the NAAQS, 

protection of PSD increments, improvement of visibility and achievement of other CAA 

objectives. 

In the Texas decision, the court evaluated the EPA’s disapproval of another SIP 

submission from the state of Texas that pertained to requirements for the permitting program for 

minor sources. The EPA had disapproved the submission for several different reasons, including 

that the Agency believed the specific provisions at issue provided the state agency with too much 

director’s discretion authority to decide what, if any, monitoring, recordkeeping and reporting 

requirements should be imposed on any individual affected source in its permit. The EPA 

concluded that if at the time it was evaluating the SIP provision for approval it could not 

reasonably anticipate how the state agency would exercise the discretion authorized in the 
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provision, this made the submission unapprovable “for being too vague and not replicable.”258

The Texas court disagreed. The court concluded that the “degree of discretion conferred on the 

TCEQ director cannot sustain the EPA’s rejection of the MRR requirements” and that the EPA 

insisted on “some undefined limit on a director’s discretion . . . based on a standard that the CAA 

does not empower the EPA to enforce.”259 

The EPA believes that the decision of the court in Texas v. EPA is also distinguishable 

with respect to the issue of whether director’s discretion provisions are consistent with CAA 

requirements. First, the Texas court based its decision primarily on the conclusion that the EPA 

had failed to identify and explain the provisions of the CAA that (i) preclude approval of SIP 

provisions that include unbounded director’s discretion or (ii) impose a requirement for 

“replicability” in the exercise of director’s discretion. The Texas court emphasized that although 

the EPA disapproved the SIP submission for failure to meet CAA requirements, the court found 

that the EPA “is yet to explain why.”260 The court further reasoned that “the EPA has invoked 

the term ‘director discretion’ as if that term were an independent and authoritative standard, and 

has not linked the term to language of the CAA.”261 Later in the opinion the court explicitly 

emphasized that because it was reviewing the EPA’s decisionmaking process in the disapproval 

action, the court could not consider any basis for the disapproval that was not articulated by the 

EPA in the rulemaking record.262 The EPA is explaining its interpretation of the relevant CAA 

provisions in this action. 

 

258 Id., 690 F.3d 670, 680. 

259 Id., 690 F.3d 670, 682. 

260 Id., 690 F.3d 670, 681. 

261 Id. 262 Id., 690 F.3d 670, 682. 
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Second, the Texas court also asserted its own conclusion that there is nothing in the CAA 

that pertains to director’s discretion in SIP provisions or to any limitations on the exercise of 

such discretion. As the court stated it: 

There is, in fact, no independent and authoritative standard in the CAA or its 

implementing regulations requiring that a state director’s discretion be cabined in the way 

that the EPA suggests. Therefore, the EPA’s insistence on some undefined limit on a 

director’s discretion is . . . based on a standard that the CAA does not empower the EPA 

to enforce. 

However, the court reached this conclusion based upon the administrative record before it and 

reiterated that it could not consider any basis for the disapproval not articulated by the EPA in 

the rulemaking record: “We are reviewing an agency’s decisionmaking process, so the agency’s 

action must be upheld, if at all, on the basis articulated by the agency itself.”263 Given the court’s 

conclusion that the EPA had failed to provide any explanation as to why the CAA precludes 

director’s discretion provisions in the challenged rulemaking, the EPA believes that the court did 

not have the opportunity to consider the Agency’s rationale that is provided in this action. In the 

February 2013 proposal and in this notice, the EPA is heeding the court’s admonishment to 

explain in the rulemaking record the statutory basis for the Agency’s interpretation of the CAA 

to prohibit director’s discretion provisions that are inadequately bounded. As explained in this 

action, SIP provisions that functionally authorize a state agency to amend existing SIP emission 

limitations applicable to a source unilaterally without a SIP revision are contrary to multiple 

specific provisions of the CAA that pertain to SIP revisions. 

Third, the Texas court emphasized that, notwithstanding the apparent flexibility that the 

director’s discretion provision provided to the state agency with respect to deciding on the level 

 

263 Id., 690 F.3d 670, 682. 
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of monitoring, recordkeeping and reporting to be imposed on each source by permit, the state’s 

regulations explicitly prohibited relaxations of the level of control. The court gave weight to the 

explicit wording of the specific provision at issue in the case which provided that “[t]he existing 

level of control may not be lessened for any facility.”264 The EPA does not agree that the specific 

requirements for monitoring, recordkeeping and reporting for a given source are unrelated to the 

level of control. In any event, the director’s discretion provisions of the type at issue in this 

action are not limited to those that would not “lessen” the level of control. To the contrary, the 

provisions at issue in this SIP call action authorize state agency personnel to grant outright 

exemptions from otherwise applicable SIP emission limitations during SSM events. Thus, the 

EPA concludes that this portion of the reasoning of the Texas decision would not apply to the 

current action. 

Finally, the Texas court viewed the fact that the EPA had previously approved similar 

director’s discretion provisions in Texas and in Georgia as evidence that such provisions must be 

consistent with CAA requirements. The EPA acknowledges that it has, from time to time, 

approved SIP submissions that it should not have, whether through failure to recognize an issue, 

through a misunderstanding of the facts, through a mistaken interpretation of the law or as a 

result of other such circumstances. Congress itself clearly recognized that the EPA may 

occasionally take incorrect action on SIP submissions, whether incorrect at the time of the action 

or as a result of later events. Section 110(k)(5) and section 110(k)(6) both provide the EPA with 

explicit authority to address past approvals of SIP submissions that turn out to have been 

mistakes, whether at the time of the original approval or as a result of later developments. The 

 

264 Id., 690 F.3d 670, 681. 
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fact that the EPA has explicit authority to issue a SIP call establishes that Congress anticipated 

that the Agency may at some point approve a SIP provision that it should not have approved 

because the provision is substantially inadequate to meet CAA requirements. The EPA does not 

agree, however, that its approval of a comparable SIP provision at some time in the past negates 

the Agency’s authority to disapprove a current SIP submission that fails to meet applicable 

procedural or substantive requirements. A challenger of the disapproval can always argue that 

the inconsistency between the prior approval and the later disapproval is evidence that the EPA 

is being arbitrary and capricious in its interpretation of the statute—but at bottom the correct 

question is whether the Agency is correctly interpreting the CAA in the disapproval action 

currently being challenged. The fact that the EPA may have approved another SIP submission 

with a comparable defect in the past does not override the requirements of the CAA. 

Significantly, the commenters apparently make the same mistake as the EPA did in the 

rulemakings at issue in the cited court decisions, by not adequately addressing the relevant 

statutory provisions that apply to SIP provisions in general and apply to revisions of existing 

EPA-approved SIP provisions in particular. The commenters failed to consider the core problem 

with unbounded director’s discretion provisions (i.e., that such provisions allow for unilateral 

revision, relaxation or exemption from SIP emission limitations, without adequate evaluation by 

the EPA and the public). As a result, the commenters do not address the proper application of 

CAA provisions that govern SIP revisions and the rationale for requiring that such SIP revisions 

be reviewed by the EPA in accordance with the explicit requirements of sections 110(k)(3), 

110(l) and 193 and the other requirements germane to the SIP provision at issue (e.g., RACTlevel controls for sources located in nonattainment areas). Indeed, the commenters did not 

acknowledge the inherent problem with director’s discretion provisions, which is that such 
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provisions have the potential to undermine SIP emission limitations dramatically through ad hoc

exemptions for excess emissions during SSM events. By allowing for exemptions for emissions 

during SSM events, these provisions also remove the incentives for sources to be properly 

designed, maintained and operated so that they will comply continuously with SIP emission 

limitations during all modes of source operation. 

The EPA notes that the commenters did not acknowledge or address the specific 

explanation that the Agency provided in the February 2013 proposal, including the EPA’s 

identification of the specific statutory provisions applicable to the revision of SIP provisions. 

Because these commenters did not address the EPA’s explanation of the CAA provisions that it 

interprets to preclude director’s discretion provisions in SIPs, the commenters have not provided 

substantive comment concerning the EPA’s interpretation of the CAA on this issue. The 

commenters did not dispute the EPA’s interpretation of the CAA on this particular point on 

statutory grounds. Rather, the commenters argued based on their own policy preferences for an 

approach to director’s discretion provisions that would allow sources to receive ad hoc

exemptions for excess emissions during SSM events without the need for imposition of an 

appropriate alternative SIP emission limitation, for adequate public process for development of 

such an alternative SIP emission limitation or for oversight by the EPA of any revision to the 

applicable SIP emission limitations as required by the CAA. 

e. Comments opposed to the EPA’s approach on the premise that there is no 

“director’s discretion” concern if the SIP provision creates a permit program through which state 

officials grant sources variances or exemptions from otherwise applicable SIP provisions. 

Comment: State commenters argued that they have imposed sufficient boundaries on the 

exercise of director’s discretion provisions in their SIPs, by virtue of the fact that they grant 
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sources variances or exemptions from SIP emission limitations through a permitting program. 

Commenters stated that their permitting program provides a more structured process and an 

opportunity for public input into the decisions concerning variances or exemptions. Moreover, 

they argued that state law does provide preconditions to the granting of variances or exemptions 

and thus these are not granted automatically. Based upon these procedural requirements, the 

commenters contended that their exercise of director’s discretion is not “unbounded” as the EPA 

suggested in the February 2013 proposal. 

The EPA acknowledges that a permitting program can provide a more structured and 

consistent process than may be provided in a SIP for granting variances and exemptions from 

SIP emission limitations and related requirements and may provide more opportunity for public 

participation in those decisions. However, to the extent that the end result of this permitting 

process is that a given source is given a less stringent emission limitation than the otherwise 

applicable SIP emission limitation or is given an outright exemption from the SIP emission 

limitation, this result still functionally constitutes a revision of the SIP emission limitation 

without meeting the statutory requirements for a SIP revision. The EPA is not authorized to 

approve a program that in essence allows a SIP revision without compliance with the applicable 

statutory requirements in sections 110(k)(3), 110(l) and 193 and any other provision that is 

germane to the particular SIP emission limitation at issue. 

The EPA emphasizes that air agencies always retain the ability to regulate sources more 

stringently than required by the provisions in its SIP. Section 116 explicitly provides, with 

certain limited exceptions, that states retain the authority to regulate emissions from sources. 

Unless preempted from controlling a particular source, nothing precludes states from regulating 

sources more stringently than otherwise required to meet CAA requirements, so long as they 
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meet CAA requirements. However, if there is an applicable emission limitation in a SIP 

provision (or an EPA regulation promulgated pursuant to sections 111 or 112), section 116 

explicitly stipulates, “such State or political subdivision may not adopt or enforce any emission 

standard or emission limitation which is less stringent than the standard or limitation under such 

plan or limitation.” Thus, a state could elect to regulate a source more stringently than required 

by a specific SIP emission limitation (e.g., by imposing a more stringent numerical emission 

limitation on a particular source or by imposing additional recordkeeping, reporting and 

monitoring requirements in addition to those of the SIP provision), but the state cannot weaken 

or eliminate the SIP emission limitation (e.g., by granting exemptions from applicable SIP 

emission limitations for emissions during SSM events). If a state elects to alter an emission 

limitation in a SIP provision, the state must do so in accordance with the statutory provisions 

applicable to SIP revisions. 

Finally, the EPA notes, if a state elects to use a permitting process as a source-by-source 

means of imposing more stringent emission limitations or additional requirements on sources, 

doing so can be an acceptable approach. So long as the underlying SIP provisions are adequate to 

provide the requisite level of control or requirements to assure enforceability, a state is free to 

use a permitting program to impose additional requirements above and beyond those provided in 

the SIP. 

D. Enforcement Discretion Provisions Pertaining to SSM Events 

1. What the EPA Proposed 

In the February 2013 proposal, the EPA explained in detail that it believes that the CAA 

allows states to adopt SIP provisions that impose reasonable limits upon the exercise of 

enforcement discretion by air agency personnel, so long as those provisions do not apply to the 
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EPA or other parties. The EPA believes that its interpretation of the CAA with respect to 

enforcement discretion provisions applicable to emissions during SSM events has been clear in 

the SSM Policy. In the 1982 SSM Guidance and the 1983 SSM Guidance, the EPA indicated that 

states could elect to adopt SIP provisions that include criteria that apply to the exercise of 

enforcement discretion by state personnel. In the 1999 SSM Guidance, the EPA emphasized that 

it would not approve such provisions if they would operate to impose the state’s enforcement 

discretion decisions upon the EPA or other parties because this would be inconsistent with 

requirements of title I of the CAA.265 The EPA acknowledged, however, that both the states and 

the Agency have failed to adhere to the CAA with respect to this issue in the past, and thus the 

need for this SIP call action to correct the existing deficiencies in SIPs. 

2. What is Being Finalized in This Action 

In order to be clear about this important point on a going-forward basis, the EPA is 

reiterating that SIP provisions cannot contain enforcement discretion provisions that would bar 

enforcement by the EPA or citizens for any violation of SIP requirements if the state elects not to 

enforce. 

 

265 See 1999 SSM Guidance at 3. 
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The EPA has previously issued a SIP call to a state specifically for purposes of clarifying 

an existing SIP provision to assure that regulated entities, regulators and courts will not 

misunderstand the correct interpretation of the provision.266 As the EPA stated in that action: 

. . . SIP provisions that give exclusive authority to a state to determine whether an 

enforcement action can be pursued for an exceedance of an emission limit are 

inconsistent with the CAA’s regulatory scheme. EPA and citizens, and any court 

in which they seek to file an enforcement claim, must retain the authority to 

independently evaluate whether a source’s exceedance of an emission limit 

warrants enforcement action.267 

3. Response to Comments 

a. Comments that supported the clarification of ambiguous enforcement discretion 

provisions in general but opposed the EPA’s views with respect to specific SIP provisions. 

Comment: Environmental group commenters disagreed with the EPA’s proposed denial 

of the Petition with respect to specific enforcement discretion provisions in the SIPs of several 

states. The commenters contended that the SIP provisions are too ambiguous for courts to 

recognize that the exercise of enforcement discretion by state personnel did not preclude 

enforcement by the EPA or others. 

Response: The EPA disagrees with these comments. In the February 2013 proposal, the 

EPA explained how it reads the specific enforcement discretion provisions in the SIPs of each of 

these states. The EPA explained its evaluation of these provisions in detail. In comments 

submitted on the February 2013 proposal, the states in question agreed with the EPA’s reading of 

the provisions. Each state agreed that these provisions only applied to air agency personnel and 

 

266 See “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah State 

Implementation Plan Revision,” 75 FR 70888 at 70892–93 (November 19, 2010) (proposed SIP 

call, inter alia, to rectify an enforcement discretion provision that in fact appeared to bar 

enforcement by the EPA or citizens if the state decided not to enforce). 

267 See id. 
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not to the EPA or any other party. Thus, the EPA believes that there should be no dispute about 

the proper interpretation of these SIP provisions in any potential future enforcement action. 

b. Comments that opposed the EPA’s issuing SIP calls to obtain state agency 

clarification of ambiguous enforcement discretion provisions in SIPs. 

Comment: One commenter asserted that requiring states to correct an ambiguous 

“enforcement discretion” provision in its SIP in order to eliminate “perceived ambiguity” is a 

“waste of resources.” Although agreeing that a state’s exercise of enforcement discretion cannot 

affect enforcement by the EPA or other parties under the citizen suit provision, the commenter 

believed that the existence of ambiguous provisions that could be misconstrued by a court to bar 

enforcement by the EPA or others if the state elects not to enforce is not a significant concern. 

Response: The EPA agrees with the commenter that a state’s legitimate exercise of 

enforcement discretion not to enforce in the event of violations of SIP provisions should have no 

bearing whatsoever on whether the EPA or others may seek to enforce for the same violations. 

However, the Agency disagrees with the commenter concerning whether some SIP provisions 

need to be clarified in order to assure that this principle is adhered to in practice in enforcement 

actions. For example, if on the face of an approved SIP provision the state appears to have the 

unilateral authority to decide that a specific event is not a “violation” or if it otherwise appears 

that if the state elects not to pursue enforcement for such violation then no other party may do so, 

then that SIP provision fails to meet fundamental legal requirements for enforcement under the 

CAA. If the SIP provision appears to provide that the decision of the state not to enforce for an 

exceedance of the SIP emission limit bars the EPA or others from bringing an enforcement 

action, then that is an impermissible imposition of the state’s enforcement discretion decisions on 

other parties. The EPA has previously issued a SIP call to resolve just such an ambiguity, and its 
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authority to do so has been upheld.268 Given that the commenter agrees with the underlying 

principle that a state’s exercise of enforcement discretion should have no bearing on the exercise 

of enforcement authority of the EPA or citizens, the Agency presumes that the commenter would 

not in fact oppose a SIP revision to clarify that point. Moreover, the commenter would not be 

harmed by such a SIP revision and would have no basis upon which to challenge it. As the 

clarification of the ambiguous SIP provision should be in the interest of all involved, including 

the regulated entities, the regulators and the public, the EPA does not believe that resources used 

to eliminate such ambiguities would be wasted. 

E. Affirmative Defense Provisions in SIPs During Any Period of Operation 

As explained in detail in the SNPR, the EPA believes that the CAA prohibits affirmative 

defense provisions in SIPs. The EPA acknowledges that since the 1999 SSM Guidance, the 

Agency had interpreted the CAA to allow narrowly tailored affirmative defense provisions. 

However, the EPA’s interpretation of the statute was based on arguments that have since been 

rejected by the D.C. Circuit in the NRDC v. EPA decision. The EPA received a substantial 

number of comments, both supportive and adverse, concerning the issue of affirmative defense 

provisions in SIPs. These comments and the EPA’s responses to them are discussed in section 

IV.D of this notice. 

F. Relationship Between SIP Provisions and Title V Regulations 

As the EPA explained in the February 2013 proposal, the SIP provisions identified in the 

Petition highlighted an area of potential ambiguity or conflict between the SSM Policy 

applicable to SIP provisions and the EPA’s regulations applicable to CAA title V operating 

 

268 See “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah State 

Implementation Plan Revision; Proposed rule,” 76 FR 21639 (April 18, 2011). 
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permit provisions. The EPA has promulgated regulations in 40 CFR part 70 applicable to state 

operating permit programs and in 40 CFR part 71 applicable to federal operating permit 

programs.269 Under each set of regulations, the EPA has provided that permits may contain, at 

the permitting authority’s discretion, an “emergency provision.”270 

The regulatory parameters applicable to such emergency provisions in operating permits 

are the same for state operating permit program regulations and the federal operating permit 

program regulations. The definition of emergency is identical in the regulations for each 

program: 

An “emergency” means any situation arising from sudden and reasonably 

unforeseeable events beyond the control of the source, including acts of God, 

which situation requires immediate corrective action to restore normal operation, 

and that causes the source to exceed a technology-based emission limitation under 

the permit, due to unavoidable increases in emissions attributable to the 

emergency. An emergency shall not include noncompliance to the extent caused 

by improperly designed equipment, lack of preventative maintenance, careless or 

improper operation or operator error.271 

Thus, if there is an emergency event meeting the regulatory definition, then the EPA’s 

regulations for operating permit programs provide for an “affirmative defense” to enforcement 

for noncompliance with technology-based standards during the emergency event, provided the 

source can demonstrate through specified forms of evidence that the event and the permittee’s 

actions during and after the event met a number of specific requirements.272 

 

269 See 40 CFR sections 70.1–70.12; 40 CFR sections 71.1–71.27. 

270 See 40 CFR 70.6(g); 40 CFR 71.6(g). The EPA also notes that states are not required to adopt 

the “emergency provision” contained in 40 CFR 70.6(g) into their state operating permit 

programs, and many states have chosen not to do so. See, e.g., “Clean Air Act Full Approval of 

Partial Operating Permit Program; Allegheny County; Pennsylvania; Direct Final Rule,” 66 FR 

55112 at 55113 (November 1, 2001).

271 See 40 CFR 70.6(g)(1); 40 CFR 71.6(g)(1). 

272 40 CFR 70.6(g)(3); 40 CFR 71.6(g)(3). 
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The Petitioner did not directly request that the EPA evaluate the existing regulatory 

provisions applicable to operating permits in 40 CFR part 70 and 40 CFR part 71, and the EPA is 

not revising those provisions in this action. In its February 2013 proposal, the EPA explained 

that while it was proposing to allow narrowly drawn affirmative defense provisions for 

malfunctions in SIPs, SIP provisions that were modeled after the regulations in 40 CFR part 70 

and 40 CFR part 71 were still in conflict with the EPA’s interpretation of the CAA for SIP 

provisions and thus could not be allowed.273 However, as explained in the SNPR, the reasoning 

in the subsequent NRDC v. EPA court decision is that even narrowly defined affirmative defense 

provisions in SIPs are no longer consistent with the CAA.274 Accordingly, regardless of whether 

affirmative defense provisions in SIPs were defined more narrowly than were the provisions 

applicable to operating permits under 40 CFR part 70 and 40 CFR part 71, they cannot be 

included in SIPs. For these reasons, the EPA has evaluated the specific SIP provisions identified 

in the Petition and is taking final action to find substantial inadequacy and to issue a SIP call for 

those SIP provisions that include features that are inappropriate for SIPs, regardless of whether 

those provisions contain terms found in other regulations. 

Additionally, we are not taking action in this rulemaking to alter the emergency 

provisions found in 40 CFR part 70 and 40 CFR part 71. Those regulations, which are applicable 

to title V operating permits, may only be changed through appropriate rulemaking to revise parts 

70 and 71. Further, any existing permits that contain such emergency provisions may only be 

changed through established permitting procedures. The EPA is considering whether to make 

changes to 40 CFR part 70 and 40 CFR part 71, and if so, how best to make those changes. In 

 

273 See February 2013 proposal, 78 FR 12459 at 12481–82. 

274 See SNPR, 79 FR 55919 at 55929–30. 
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any such action, EPA would also intend to address the timing of any changes to existing title V 

operating permits. Until that time, as part of normal permitting process, the EPA encourages 

permitting authorities to consider the discretionary nature of the emergency provisions when 

determining whether to continue to include permit terms modeled on those provisions in 

operating permits that the permitting authorities are issuing in the first instance or renewing. 

G. Intended Effect of the EPA’s Action on the Petition 

As in the 2001 SSM Guidance, the EPA is endeavoring to be particularly clear about the 

intended effect of its final action on the Petition, of its clarifications and revisions to the SSM 

Policy and of its application of the updated SSM Policy to the specific existing SIP provisions 

discussed in section IX of this document. 

First, the EPA only intends its actions on the larger policy or legal issues raised by the 

Petitioner to inform the public of the EPA’s current views on the requirements of the CAA with 

respect to SIP provisions related to SSM events. Thus, for example, the EPA’s proposed grant of 

the Petitioner’s request that the EPA interpret the CAA to disallow all affirmative defense 

provisions is intended to convey that the EPA has changed its views about such provisions and 

that its prior views expressed in the 1999 SSM Guidance and related rulemakings on SIP 

submissions were incorrect. In this fashion, the EPA’s action on the Petition provides updated 

guidance relevant to future SIP actions. 

Second, the EPA only intends its actions on the specific existing SIP provisions identified 

in the Petition to be applicable to those provisions. The EPA does not intend its action on those 

specific provisions to alter the current status of any other existing SIP provisions relating to SSM 

events. The EPA must take later rulemaking actions, if necessary, in order to evaluate any 

comparable deficiencies in other existing SIP provisions that may be inconsistent with the 
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requirements of the CAA. Again, however, the EPA’s actions on the Petition provide updated 

guidance on the types of SIP provisions that it believes would be consistent with CAA 

requirements in future rulemaking actions. 

Third, the EPA does not intend its action on the Petition to affect immediately any 

existing permit terms or conditions regarding excess emissions during SSM events that reflect 

previously approved SIP provisions. The EPA’s finding of substantial inadequacy and a SIP call 

for a given state provides the state time to revise its SIP in response to the SIP call through the 

necessary state and federal administrative process. Thereafter, any needed revisions to existing 

permits will be accomplished in the ordinary course as the state issues new permits or reviews 

and revises existing permits. The EPA does not intend the issuance of a SIP call to have 

automatic impacts on the terms of any existing permit. 

Fourth, the EPA does not intend its action on the Petition to alter the emergency defense 

provisions at 40 CFR 70.6(g) and 40 CFR 71.6(g), i.e., the title V regulations pertaining to 

“emergency provisions” permissible in title V operating permits. The EPA’s regulations 

applicable to title V operating permits may only be changed through appropriate rulemaking 

procedures and existing permit terms may only be changed through established permitting 

processes. 

Fifth, the EPA does not intend its interpretations of the requirements of the CAA in this 

action on the Petition to be legally dispositive with respect to any particular current enforcement 

proceedings in which a violation of SIP emission limitations is alleged to have occurred. The 

EPA handles enforcement matters by assessing each situation, on a case-by-case basis, to 

determine the appropriate response and resolution. For purposes of alleged violations of SIP 
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provisions, however, the terms of the applicable SIP provision will continue to govern until that 

provision is revised following the appropriate process for SIP revisions, as required by the CAA. 

Finally, the EPA does intend this final action, developed through notice and comment, to 

be the statement of its most current SSM Policy, reflecting the EPA’s interpretation of CAA 

requirements applicable to SIP provisions related to excess emissions during SSM events. In this 

regard, the EPA is adding to and clarifying its prior statements in the 1999 SSM Guidance and 

making the specific changes to that guidance as discussed in this action. Thus, this final notice 

for this action will constitute the EPA’s SSM Policy on a going-forward basis. 

VIII. Legal Authority, Process and Timing for SIP Calls 

A. SIP Call Authority Under Section 110(k)(5) 

1. General Statutory Authority 

The CAA provides a mechanism for the correction of flawed SIPs, under CAA section 

110(k)(5), which provides: 

(5) Calls for plan revisions 

Whenever the Administrator finds that the applicable implementation plan 

for any area is substantially inadequate to attain or maintain the relevant national 

ambient air quality standards, to mitigate adequately the interstate pollutant 

transport described in section [176A] of this title or section [184] of this title, or to 

otherwise comply with any requirement of [the Act], the Administrator shall 

require the State to revise the plan as necessary to correct such inadequacies. The 

Administrator shall notify the State of the inadequacies and may establish 

reasonable deadlines (not to exceed 18 months after the date of such notice) for 

the submission of such plan revisions. 

By its explicit terms, this provision authorizes the EPA to find that a state’s existing SIP 

is “substantially inadequate” to meet CAA requirements and, based on that finding, to “require 
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the State to revise the [SIP] as necessary to correct such inadequacies.” This type of action is 

commonly referred to as a “SIP call.”275 

Significantly, CAA section 110(k)(5) explicitly authorizes the EPA to issue a SIP call 

“whenever” the EPA makes a finding that the existing SIP is substantially inadequate, thus 

providing authority for the EPA to take action to correct existing inadequate SIP provisions even 

long after their initial approval, or even if the provisions only become inadequate due to 

subsequent events.276 The statutory provision is worded in the present tense, giving the EPA 

authority to rectify any deficiency in a SIP that currently exists, regardless of the fact that the 

EPA previously approved that particular provision in the SIP and regardless of when that 

approval occurred. 

 

275 The EPA also has other discretionary authority to address incorrect SIP provisions, such as 

the authority in CAA section 110(k)(6) for the EPA to correct errors in prior SIP approvals. The 

authority in CAA section 110(k)(5) and CAA section 110(k)(6) can sometimes overlap and offer 

alternative mechanisms to address problematic SIP provisions. In this instance, the EPA believes 

that the mechanism provided by CAA section 110(k)(5) is the better approach, because using the 

mechanism of the CAA section 110(k)(6) error correction would eliminate the affected emission 

limitations from the SIP potentially leaving no emission limitation in place, whereas the 

mechanism of the CAA section 110(k)(5) SIP call will keep the provisions in place during the 

pendency of the state’s revision of the SIP and the EPA’s action on that revision. In the case of 

provisions that include impermissible automatic exemptions or discretionary exemptions, the 

EPA believes that retention of the existing SIP provision is preferable to the absence of the 

provision in the interim. 

276 See, e.g., Michigan v. EPA, 213 F.3d 663 (D.C. Cir. 2000) (upholding the “NOx SIP Call” to 

states requiring revisions to previously approved SIPs with respect to ozone transport and section 

110(a)(2)(D)(i)(I)); “Action to Ensure Authority To Issue Permits Under the Prevention of 

Significant Deterioration Program to Sources of Greenhouse Gas Emissions: Finding of 

Substantial Inadequacy and SIP Call; Final Rule,” 75 FR 77698 (December 13, 2010) (the EPA 

issued a SIP call to 13 states because the endangerment finding for GHGs meant that these 

previously approved SIPs were substantially inadequate because they did not provide for the 

regulation of GHGs in the PSD permitting programs of these states as required by CAA section 

110(a)(2)(C) and section 110(a)(2)(J)); “Finding of Substantial Inadequacy of Implementation 

Plan; Call for Utah State Implementation Plan Revision,” 74 FR 21639 (April 18, 2011) (the 

EPA issued a SIP call to rectify SIP provisions dating back to 1980). 
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It is also important to emphasize that CAA section 110(k)(5) expressly directs the EPA to 

take action if the SIP provision is substantially inadequate, not just for purposes of attainment or 

maintenance of the NAAQS but also for purposes of “any requirement” of the CAA. The EPA 

interprets this reference to “any requirement” of the CAA on its face to authorize reevaluation of 

an existing SIP provision for compliance with those statutory and regulatory requirements that 

are germane to the SIP provision at issue. Thus, for example, a SIP provision that is intended to 

be an “emission limitation” for purposes of a nonattainment plan for purposes of the 1997 PM2.5

NAAQS must meet various applicable statutory and regulatory requirements, including 

requirements of CAA section 110(a)(2)(A) such as enforceability, the definition of the term 

“emission limitation” in CAA section 302(k), the level of emissions control required to constitute 

a “reasonably available control measure” in CAA section 172(c)(1) and the other applicable 

statutory requirements for the implementation of the 1997 PM2.5 NAAQS. Failure to meet any of 

those applicable requirements could constitute a substantial inadequacy suitable for a SIP call, 

depending upon the facts and circumstances. By contrast, that same SIP provision should not be 

expected to meet specifications of the CAA that are completely irrelevant for its intended 

purpose, such as the unrelated requirement of CAA section 110(a)(2)(G) that the state have 

general legal authority comparable to CAA section 303 for emergencies. 

Use of the term “any requirement” in CAA section 110(k)(5) also reflects the fact that 

SIP provisions could be substantially inadequate for widely differing reasons. One provision 

might be substantially inadequate because it fails to prohibit emissions that contribute to 

violations of the NAAQS in downwind areas many states away. Another provision, or even the 

same provision, could be substantially inadequate because it also infringes on the legal right of 

members of the public who live adjacent to the source to enforce the SIP. Thus, the EPA has 
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previously interpreted CAA section 110(k)(5) to authorize a SIP call to rectify SIP inadequacies 

of various kinds, both broad and narrow in terms of the scope of the SIP revisions required.277

On its face, CAA section 110(k)(5) authorizes the EPA to take action with respect to SIP 

provisions that are substantially inadequate to meet any CAA requirements, including 

requirements relevant to the proper treatment of excess emissions during SSM events. 

An important baseline question is whether a given deficiency renders the SIP provision 

“substantially inadequate.” The EPA notes that the term “substantially inadequate” is not defined 

in the CAA. Moreover, CAA section 110(k)(5) does not specify a particular form of analysis or 

methodology that the EPA must use to evaluate SIP provisions for substantial inadequacy. Thus, 

under Chevron step 2, the EPA is authorized to interpret this provision reasonably, consistent 

with the provisions of the CAA. In addition, the EPA is authorized to exercise its discretion in 

applying this provision to determine whether a given SIP provision is substantially inadequate. 

To the extent that the term “substantially inadequate” is ambiguous, the EPA believes that it is 

reasonable to interpret the term in light of the specific purposes for which the SIP provision at 

 

277 See, e.g., “Finding of Significant Contribution and Rulemaking for Certain States in the 

Ozone Transport Assessment Group Region for Purposes of Reducing Regional Transport of 

Ozone,” 63 FR 57356 (October 27, 1998) (the EPA issued a SIP call to 23 states requiring them 

to rectify the failure to address interstate transport of pollutants as required by section 

110(a)(2)(D); “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah State 

Implementation Plan Revision,” 74 FR 21639 (April. 18, 2011) (the EPA issued a SIP call to one 

state requiring it to rectify several very specific SIP provisions). 
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issue is required, and thus whether the provision meets the fundamental CAA requirements 

applicable to such a provision. 

The EPA does not interpret CAA section 110(k)(5) to require a showing that the effect of 

a SIP provision that is facially inconsistent with CAA requirements is causally connected to a 

particular adverse impact. For example, the plain language of CAA section 110(k)(5) does not 

require direct causal evidence that excess emissions have occurred during a specific malfunction 

at a specific source and have literally caused a violation of the NAAQS in order to conclude that 

the SIP provision is substantially inadequate.278 A SIP provision that purports to exempt a source 

from compliance with applicable emission limitations during SSM events, contrary to the 

requirements of the CAA for continuous emission limitations, does not become legally 

permissible merely because there is not definitive evidence that any excess emissions have 

resulted from the exemption and have literally caused a specific NAAQS violation.279 

Similarly, the EPA does not interpret CAA section 110(k)(5) to require direct causal 

evidence that a SIP provision that improperly undermines enforceability of the SIP has resulted 

 

278 See US Magnesium, LLC v. EPA, 690 F.3d 1157 (10th Cir. 2012) (upholding the EPA’s 

interpretation of section 110(k)(5) to authorize a SIP call when the SIP provisions are 

inconsistent with CAA requirements). 

279 The EPA notes that the GHG SIP call did not require “proof” that the failure of a state to 

address GHGs in a given PSD permit “caused” particularized environmental impacts; it was 

sufficient that the state’s SIP failed to meet the current fundamental legal requirements for 

regulation of GHGs in accordance with the CAA. See “Action to Ensure Authority To Issue 

Permits Under the Prevention of Significant Deterioration Program to Sources of Greenhouse 

Gas Emissions: Finding of Substantial Inadequacy and SIP Call; Final Rule,” 75 FR 77698 

(December 13, 2010). 
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in a specific failed enforcement attempt by any party. A SIP provision that has the practical 

effect of barring enforcement by the EPA or through a citizen suit, either because it would bar 

enforcement if an air agency elects to grant a discretionary exemption or to exercise its own 

enforcement discretion, is inconsistent with fundamental requirements of the CAA.280 Such a 

provision also does not become legally permissible merely because there is not definitive 

evidence that the state’s action literally undermined a specific attempted enforcement action by 

other parties. Indeed, the EPA notes that these impediments to effective enforcement likely have 

a chilling effect on potential enforcement in general. The possibility for effective enforcement of 

emission limitations in SIPs is itself an important principle of the CAA, as embodied in CAA 

sections 113 and 304. 

The EPA’s interpretation of CAA section 110(k)(5) is that the fundamental integrity of 

the CAA’s SIP process and structure are undermined if emission limitations relied upon to meet 

CAA requirements related to protection of public health and the environment can be violated 

without potential recourse. For example, the EPA does not believe that it is authorized to issue a 

SIP call to rectify an impermissible automatic exemption provision only after a violation of the 

NAAQS has occurred, or only if that NAAQS violation can be directly linked to the excess 

emissions that resulted from the impermissible automatic exemption by a particular source on a 

particular day. If the SIP contains a provision that is inconsistent with fundamental requirements 

of the CAA, that renders the SIP provision substantially inadequate. 

 

280 See “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah State 

Implementation Plan Revision,” 74 FR 21639 at 21641 (April 18, 2011); see also US 

Magnesium, LLC v. EPA, 690 F.3d 1157, 1168 (10th Cir. 2012) (upholding the EPA’s 

interpretation of section 110(k)(5) to authorize a SIP call when the state’s SIP provision worded 

so that state decisions whether a given excess emissions event constituted a violation interfered 

with enforcement by the EPA or citizens for such event). 
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The EPA notes that CAA section 110(k)(5) can also be an appropriate tool to address 

ambiguous SIP provisions that could be read by a court in a way that would violate the 

requirements of the CAA. For example, if an existing SIP provision concerning the state’s 

exercise of enforcement discretion is sufficiently ambiguous that it could be construed to 

preclude enforcement by the EPA or through a citizen suit if the state elects to deem a given 

SSM event not a violation, then that could render the provision substantially inadequate by 

interfering with the enforcement structure of the CAA.281 If a court could construe the 

ambiguous SIP provision to bar enforcement, then the EPA believes that it may be appropriate to 

take action to eliminate that uncertainty by requiring the state to revise the ambiguous SIP 

provision. Under such circumstances, it may be appropriate for the EPA to issue a SIP call to 

assure that the SIP provisions are sufficiently clear and consistent with CAA requirements on 

their face.282 

In this instance, the Petition raised questions concerning the adequacy of existing SIP 

provisions that pertain to the treatment of excess emissions during SSM events. The SIP 

provisions identified by the Petitioner generally fall into four major categories: (i) automatic 

 

281 Courts have on occasion interpreted SIP provisions to limit the EPA’s enforcement authority 

as a result of ambiguous SIP provisions. See, e.g., U.S. v. Ford Motor Co., 736 F.Supp. 1539 

(W.D. Mo. 1990) and U.S. v. General Motors Corp., 702 F. Supp. 133 (N.D. Texas 1988) (the 

EPA could not pursue enforcement of SIP emission limitations where states had approved 

alternative emission limitations under procedures the EPA had approved in the SIP); Florida 

Power & Light Co. v. Costle, 650 F.2d 579, 588 (5th Cir. 1981) (the EPA to be accorded no 

discretion in interpreting state law). The EPA does not agree with the holdings of these cases, but 

they illustrate why it is reasonable to eliminate any uncertainty about enforcement authority by 

requiring a state to remove or revise a SIP provision that could be read in a way inconsistent with 

the requirements of the CAA. 

282 See US Magnesium, LLC v. EPA, 690 F.3d 1157, 1170 (10th Cir. 2012) (upholding the EPA’s 

use of SIP call authority in order to clarify language in the SIP that could be read to violate the 

CAA, even if a court has not yet interpreted the language in that way). 
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exemptions; (ii) exemptions as a result of director’s discretion; (iii) provisions that appear to bar 

enforcement by the EPA or through a citizen suit if the state decides not to enforce through 

exercise of enforcement discretion; and (iv) affirmative defense provisions that purport to limit 

or eliminate a court’s jurisdiction to assess liability and impose remedies for exceedances of SIP 

emission limitations. The EPA believes that each of these types of SIP deficiency potentially 

justifies a SIP call pursuant to CAA section 110(k)(5), if the Agency determines that a SIP call is 

the proper means to rectify an existing deficiency in a SIP. 

2. Substantial Inadequacy of Automatic Exemptions 

The EPA believes that SIP provisions that provide an automatic exemption from 

otherwise applicable emission limitations are substantially inadequate to meet CAA 

requirements. A typical SIP provision that includes an impermissible automatic exemption would 

provide that a source has to meet a specific emission limitation, except during startup, shutdown 

and malfunction, and by definition any excess emissions during such events would not be 

violations and thus there could be no enforcement based on those excess emissions. The EPA’s 

interpretation of CAA requirements for SIP provisions has been reiterated multiple times through 

the SSM Policy and actions on SIP submissions that pertain to this issue. The EPA’s 

longstanding view is that SIP provisions that include automatic exemptions for excess emissions 

during SSM events, such that the excess emissions during those events are not considered 

violations of the applicable emission limitations, do not meet CAA requirements. Such 

exemptions undermine the attainment and maintenance of the NAAQS, protection of PSD 

increments and improvement of visibility, and SIP provisions that include such exemptions fail 

to meet these and other fundamental requirements of the CAA. 
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The EPA interprets CAA sections 110(a)(2)(A) and 110(a)(2)(C) to require that SIPs 

contain “emission limitations” to meet CAA requirements. Pursuant to CAA section 302(k), 

those emission limitations must be “continuous.” Automatic exemptions from otherwise 

applicable emission limitations thus render those limits less than continuous as required by CAA 

sections 302(k), 110(a)(2)(A) and 110(a)(2)(C), thereby inconsistent with a fundamental 

requirement of the CAA and thus substantially inadequate as contemplated in CAA section 

110(k)(5). 

This inadequacy has far-reaching impacts. For example, air agencies rely on emission 

limitations in SIPs in order to provide for attainment and maintenance of the NAAQS. These 

emission limitations are basic building blocks for SIPs, often used by air agencies to meet 

various requirements including: (i) in the estimates of emissions for emissions inventories; (ii) in 

the determination of what level of emissions meets various statutory requirements such as 

“reasonably available control measures” in nonattainment SIPs or “best available retrofit 

technology” in regional haze SIPs; and (iii) in critical modeling exercises such as attainment 

demonstration modeling for nonattainment areas or increment use for PSD permitting purposes. 

Because the NAAQS are not directly enforceable against individual sources, air agencies 

rely on the adoption and enforcement of these generic and specific emission limitations in SIPs 

in order to provide for attainment and maintenance of the NAAQS, protection of PSD increments 

and improvement of visibility, and to meet other CAA requirements. Automatic exemption 

provisions for excess emissions eliminate the possibility of enforcement for what would 

otherwise be clear violations of the relied-upon emission limitations and thus eliminate any 

opportunity to obtain injunctive relief that may be needed to protect the NAAQS or meet other 

CAA requirements. Likewise, the elimination of any possibility for penalties for what would 
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otherwise be clear violations of the emission limitations, regardless of the conduct of the source, 

eliminates any opportunity for penalties to encourage appropriate design, operation and 

maintenance of sources and to encourage efforts by source operators to prevent and to minimize 

excess emissions in order to protect the NAAQS or to meet other CAA requirements. Removal 

of this monetary incentive to comply with the SIP reduces a source’s incentive to design, 

operate, and maintain its facility to meet emission limitations at all times. 

3. Substantial Inadequacy of Director’s Discretion Exemptions 

The EPA believes that SIP provisions that allow discretionary exemptions from otherwise 

applicable emission limitations are substantially inadequate to meet CAA requirements for the 

same reasons as automatic exemptions, but for additional reasons as well. A typical SIP 

provision that includes an impermissible “director’s discretion” component would purport to 

authorize air agency personnel to modify existing SIP requirements under certain conditions, 

e.g., to grant a variance from an otherwise applicable emission limitation if the source could not 

meet the requirement in certain circumstances.283 If such provisions are sufficiently specific, 

provide for sufficient public process and are sufficiently bounded, so that it is possible to 

anticipate at the time of the EPA’s approval of the SIP provision how that provision will actually 

be applied and the potential adverse impacts thereof, then such a provision might meet basic 

CAA requirements. In essence, if it is possible to anticipate and evaluate in advance how the 

exercise of enforcement discretion could impact compliance with other CAA requirements, then 

 

283 The EPA notes that problematic “director’s discretion” provisions are not limited only to 

those that purport to authorize alternative emission limitations from those required in a SIP. 

Other problematic director’s discretion provisions could include those that purport to provide for 

discretionary changes to other substantive requirements of the SIP, such as applicability, 

operating requirements, recordkeeping requirements, monitoring requirements, test methods, and 

alternative compliance methods. 
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it may be possible to determine in advance that the preauthorized exercise of director’s discretion 

will not interfere with other CAA requirements, such as providing for attainment and 

maintenance of the NAAQS. Most director’s discretion-type provisions cannot meet this basic 

test. 

Unless it is possible at the time of the approval of the SIP provision to anticipate and 

analyze the impacts of the potential exercise of the director’s discretion, such provisions 

functionally could allow de facto revisions of the approved emission limitations required by the 

SIP without complying with the process for SIP revisions required by the CAA. Sections 

110(a)(1) and (2) of the CAA impose procedural requirements on states that seek to amend SIP 

provisions. The elements of CAA section 110(a)(2) and other sections of the CAA, depending 

upon the subject of the SIP provision at issue, impose substantive requirements that states must 

meet in a SIP revision. Section 110(i) of the CAA prohibits modification of SIP requirements for 

stationary sources by either the state or the EPA, except through specified processes.284 Section 

 

284 Section 110(i) of the Act states that “no order, suspension, plan revision or other action 

modifying any requirement of an applicable implementation plan may be taken with respect to 

any stationary source by the State or by the Administrator” except in compliance with the CAA’s 

requirements for promulgation or revision of a plan, with limited exceptions. See, e.g., 

“Approval and Disapproval and Promulgation of Air Quality Implementation Plans; Colorado; 

Revisions to Regulation 1; Notice of proposed rulemaking,” 75 FR 42342 at 42344 (July 21, 

2010) (proposing to disapprove “director discretion” provisions as inconsistent with CAA 

requirements and noting that “[s]ection 110(i) specifically prohibits States, except in certain 

limited circumstances, from taking any action to modify any requirement of a SIP with respect to 

any stationary source, except through a SIP revision”), finalized as proposed at 76 FR 4540 

(January 26, 2011); “Corrections to the California State Implementation Plan,” 69 FR 67062 at 

67063 (November 16, 2004) (noting that “a state-issued variance, though binding as a matter of 

State law, does not prevent EPA from enforcing the underlying SIP provisions unless and until 

EPA approves that variance as a SIP revision”); Industrial Environmental Association v. 

Browner, No. 97-71117 at n.2 (9th Cir. May 26, 2000) (noting that the EPA has consistently 

treated individual variances granted under state variance provisions as “modifications of the SIP 

requiring independent EPA approval”). 
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110(k) of the CAA imposes procedural and substantive requirements on the EPA for action upon 

any SIP revision. Sections 110(l) and 193 of the CAA both impose additional procedural and 

substantive requirements on the state and the EPA in the event of a SIP revision. Chief among 

these many requirements for a SIP revision would be the necessary demonstration that the SIP 

revision in question would not interfere with any requirement concerning attainment and 

reasonable further progress or “any other applicable requirement of” the CAA to meet the 

requirements of CAA section 110(l). 

Congress presumably imposed these many explicit requirements in order to assure that 

there is adequate public process at both the air agency and federal level for any SIP revision and 

to assure that any SIP revision meets the applicable substantive requirements of the CAA. 

Although no provision of the CAA explicitly addresses whether a “director’s discretion” 

provision by that term is acceptable, the EPA interprets the statute to prohibit such provisions 

unless they would be consistent with the statutory and regulatory requirements that apply to SIP 

revisions.285 A SIP provision that purports to give broad and unbounded director’s discretion to 

alter the existing legal requirements of the SIP with respect to meeting emission limitations 

would be tantamount to allowing a revision of the SIP without meeting the applicable procedural 

 

285 See, e.g., EPA’s implementing regulations at 40 CFR 51.104(d) (“In order for a variance to be 

considered for approval as a revision to the [SIP], the State must submit it in accordance with the 

requirements of this section”) and 51.105 (“Revisions of a plan, or any portion thereof, will not 

be considered part of an applicable plan until such revisions have been approved by the 

Administrator in accordance with this part.”). 
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and substantive requirements for such a SIP revision. The EPA’s approval of a SIP provision that 

purported to allow unilateral revisions of the emission limitations in the SIP by the state, without 

complying with the statutory requirements for a SIP revision, would itself be contrary to 

fundamental procedural and substantive requirements of the CAA. 

For this reason, the EPA has long discouraged the creation of new SIP provisions 

containing an impermissible director’s discretion feature and has also taken actions to remove 

existing SIP provisions that it had previously approved in error.286 In recent years, the EPA has 

also recommended that if an air agency elects to have SIP provisions that contain a director’s 

discretion feature, then to be consistent with CAA requirements the provisions must be 

structured so that any resulting variances or other deviations from the emission limitation or 

other SIP requirements have no federal law validity, unless and until the EPA specifically 

approves that exercise of the director’s discretion as a SIP revision. Barring such a later 

ratification by the EPA through a SIP revision, the exercise of director’s discretion is only valid 

for state (or tribal) law purposes and would have no bearing in the event of an action to enforce 

the provision of the SIP as it was originally approved by the EPA. 

 

286 See, e.g., “Approval and Disapproval and Promulgation of Air Quality Implementation Plans; 

Colorado; Revisions to Regulation 1,” 76 FR 4540 (January 26, 2011) (partial disapproval of SIP 

submission based on inclusion of impermissible director’s discretion provisions); “Correction of 

Implementation Plans; American Samoa, Arizona, California, Hawaii, and Nevada State 

Implementation Plans; Notice of proposed rulemaking,” 61 FR 38664 (July 25, 1996) (proposed 

SIP correction to remove, pursuant to CAA section 110(k)(6), several variance provisions from 

American Samoa, Arizona, California, Hawaii, and Nevada SIPs), finalized at 62 FR 34641 

(June 27, 1997); “Approval and Promulgation of Implementation Plans; Corrections to the 

Arizona and Nevada State Implementation Plans,” 74 FR 57051 (November 3, 2009) (direct final 

rulemaking to remove, pursuant to CAA section 110(k)(6), variance provisions from Arizona and 

Nevada SIPs). 
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The EPA’s evaluation of the specific SIP provisions of this type identified in the Petition 

indicates that none of them provides sufficient process or sufficient bounds on the exercise of 

director’s discretion to be permissible. Most on their face would allow potentially limitless 

exemptions from SIP requirements with potentially dramatic adverse impacts inconsistent with 

the objectives of the CAA. More importantly, however, each of the identified SIP provisions 

goes far beyond the limits of what might theoretically be a permissible director’s discretion 

provision, by authorizing state personnel to create case-by-case exemptions from the applicable 

emission limitations or other requirements of the SIP for excess emissions during SSM events. 

Given that the EPA interprets the CAA not to allow exemptions from SIP emission limitations 

for excess emissions during SSM events in the first instance, it follows that providing such 

exemptions through the ad hoc mechanism of a director’s discretion provision is also not 

permissible and compounds the problem. 

As with automatic exemptions for excess emissions during SSM events, a provision that 

allows discretionary exemptions would not meet the statutory requirements of CAA sections 

110(a)(2)(A) and 110(a)(2)(C) that require SIPs to contain “emission limitations” to meet CAA 

requirements. Pursuant to CAA section 302(k), those emission limitations must be “continuous.” 

Discretionary exemptions from otherwise applicable emission limitations render those limits less 

than continuous, as is required by CAA sections 110(a)(2)(A) and 110(a)(2)(C), and thereby 

inconsistent with a fundamental requirement of the CAA and thus substantially inadequate as 

contemplated in section CAA 110(k)(5). Such exemptions undermine the objectives of the CAA 

such as protection of the NAAQS and PSD increments, and they fail to meet other fundamental 

requirements of the CAA. 
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In addition, discretionary exemptions undermine effective enforcement of the SIP by the 

EPA or through a citizen suit, because often there may have been little or no public process 

concerning the exercise of director’s discretion to grant the exemptions, or easily accessible 

documentation of those exemptions, and thus even ascertaining the possible existence of such ad 

hoc exemptions will further burden parties who seek to evaluate whether a given source is in 

compliance or to pursue enforcement if it appears that the source is not. Where there is little or 

no public process concerning such ad hoc exemptions, or there is inadequate access to relevant 

documentation of those exemptions, enforcement by the EPA or through a citizen suit may be 

severely compromised. As explained in the 1999 SSM Guidance, the EPA does not interpret the 

CAA to allow SIP provisions that would allow the exercise of director’s discretion concerning 

violations to bar enforcement by the EPA or through a citizen suit. The exercise of director’s 

discretion to exempt conduct that would otherwise constitute a violation of the SIP would 

interfere with effective enforcement of the SIP. Such provisions are inconsistent with and 

undermine the enforcement structure of the CAA provided in CAA sections 113 and 304, which 

provide independent authority to the EPA and citizens to enforce SIP provisions, including 

emission limitations. Thus, SIP provisions that allow discretionary exemptions from applicable 

SIP emission limitations through the exercise of director’s discretion are substantially inadequate 

to comply with CAA requirements as contemplated in CAA section 110(k)(5). 

4. Substantial Inadequacy of Improper Enforcement Discretion Provisions 

The EPA believes that SIP provisions that pertain to enforcement discretion but could be 

construed to bar enforcement by the EPA or through a citizen suit if the air agency declines to 

enforce are substantially inadequate to meet CAA requirements. A typical SIP provision that 

includes an impermissible enforcement discretion provision specifies certain parameters for 
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when air agency personnel should pursue enforcement action, but is worded in such a way that 

the air director’s decision defines what constitutes a “violation” of the emission limitation for 

purposes of the SIP, i.e., by defining what constitutes a violation, the air agency’s own 

enforcement discretion decisions are imposed on the EPA or citizens.287 

The EPA’s longstanding view is that SIP provisions cannot enable an air agency’s 

decision concerning whether or not to pursue enforcement to bar the ability of the EPA or the 

public to enforce applicable requirements.288 Such enforcement discretion provisions in a SIP 

would be inconsistent with the enforcement structure provided in the CAA. Specifically, the 

statute provides explicit independent enforcement authority to the EPA under CAA section 113 

and to citizens under CAA section 304. Thus, the CAA contemplates that the EPA and citizens 

have authority to pursue enforcement for a violation even if the air agency elects not to do so. 

The EPA and citizens, and any court in which they seek to pursue an enforcement claim for 

violation of SIP requirements, must retain the authority to evaluate independently whether a 

source’s violation of an emission limitation warrants enforcement action. Potential for 

enforcement by the EPA or through a citizen suit provides an important safeguard in the event 

that the air agency lacks resources or ability to enforce violations and provides additional 

deterrence. Accordingly, a SIP provision that operates at the air agency’s election to eliminate 

the authority of the EPA or the public to pursue enforcement actions would undermine the 

 

287 See, e.g., “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah State 

Implementation Plan Revision,” 75 FR 70888 at 70892 (November 19, 2010). The SIP provision 

at issue provided that information concerning a malfunction “shall be used by the executive 

secretary in determining whether a violation has occurred and/or the need of further enforcement 

action.” This SIP language appeared to give the state official exclusive authority to determine 

whether excess emissions constitute a violation. 

288 See 1999 SSM Guidance at 3. 
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enforcement structure of the CAA and would thus be substantially inadequate to meet 

fundamental requirements in CAA sections 113 and 304. 

5. Substantial Inadequacy of Affirmative Defense Provisions 

The EPA believes that SIP provisions that provide an affirmative defense for excess 

emissions during SSM events are substantially inadequate to meet CAA requirements. A typical 

SIP provision that includes an impermissible affirmative defense operates to limit or eliminate 

the jurisdiction of federal courts to assess liability or to impose remedies in an enforcement 

proceeding for exceedances of SIP emission limitations. Some affirmative defense provisions 

apply broadly, whereas others are components of specific emission limitations. Some provisions 

use the explicit term “affirmative defense,” whereas others are structured as such provisions but 

do not use this specific terminology. All of these provisions, however, share the same legal 

deficiency in that they purport to alter the statutory jurisdiction of federal courts under section 

113 and section 304 to determine liability and to impose remedies for violations of CAA 

requirements, including SIP emission limitations. Accordingly, an affirmative defense provision 

that operates to limit or to eliminate the jurisdiction of the federal courts would undermine the 

enforcement structure of the CAA and would thus be substantially inadequate to meet 

fundamental requirements in CAA sections 113 and 304. By undermining enforcement, such 

provisions also are inconsistent with fundamental CAA requirements such as attainment and 

maintenance of the NAAQS, protection of PSD increments and improvement of visibility. 

B. SIP Call Process Under Section 110(k)(5) 

Section 110(k)(5) of the CAA provides the EPA with authority to determine whether a 

SIP is substantially inadequate to attain or maintain the NAAQS or otherwise comply with any 
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requirement of the CAA. Where the EPA makes such a determination, the EPA then has a duty 

to issue a SIP call. 

In addition to providing general authority for a SIP call, CAA section 110(k)(5) sets forth 

the process and timing for such an action. First, the statute requires the EPA to notify the state of 

the final finding of substantial inadequacy. The EPA typically provides notice to states by a letter 

from the Assistant Administrator for the Office of Air and Radiation to the appropriate state 

officials in addition to publication of the final action in the Federal Register. 

Second, the statute requires the EPA to establish “reasonable deadlines (not to exceed 18 

months after the date of such notice)” for states to submit corrective SIP submissions to 

eliminate the inadequacy in response to the SIP call. The EPA proposes and takes comment on 

the schedule for the submission of corrective SIP revisions in order to ascertain the appropriate 

timeframe, depending on the nature of the SIP inadequacy. 

Third, the statute requires that any finding of substantial inadequacy and notice to the 

state be made public. By undertaking a notice-and-comment rulemaking, the EPA assures that 

the air agencies, affected sources and members of the public all are adequately informed and 

afforded the opportunity to participate in the process. Through the February 2013 proposal, the 

SNPR and this final notice, the EPA is providing a full evaluation of the issues raised by the 

Petition and has used this process as a means of giving clear and up-to-date guidance concerning 

SIP provisions relevant to the treatment of excess emissions during SSM events that is consistent 

with CAA requirements. 

If the state fails to submit the corrective SIP revision by the deadline established in this 

final notice, CAA section 110(c) authorizes the EPA to “find[] that [the] State has failed to make 
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a required submission.”289 Once the EPA makes such a finding of failure to submit, CAA section 

110(c)(1) requires the EPA to “promulgate a Federal implementation plan at any time within 2 

years after the [finding] . . . unless the State corrects the deficiency, and [the EPA] approves the 

plan or plan revision, before [the EPA] promulgates such [FIP].” Thus, if the EPA finds that the 

air agency failed to submit a complete SIP revision that responds to this SIP call, or if the EPA 

disapproves such SIP revision, then the EPA will have an obligation under CAA section 

110(c)(1) to promulgate a FIP no later than 2 years from the date of the finding or the 

disapproval, if the deficiency has not been corrected before that time.290 

The finding of failure to submit a revision in response to a SIP call, or the EPA’s 

disapproval of that corrective SIP revision, can also trigger sanctions under CAA section 179. If 

a state fails to submit a complete SIP revision that responds to a SIP call, CAA section 179(a) 

provides for the EPA to issue a finding of state failure. Such a finding starts mandatory 18-month 

and 24-month sanctions clocks. The two sanctions that apply under CAA section 179(b) are the 

2-to-1 emission offset requirement for all new and modified major sources subject to the 

nonattainment new source review program and restrictions on highway funding. However, 

section 179 leaves it to the EPA to decide the order in which these sanctions apply. The EPA 

issued an order of sanctions rule in 1994 but did not specify the order of sanctions where a state 

fails to submit or submits a deficient SIP revision in response to a SIP call.291 In the February 

2013 proposal, as the EPA has done in other SIP calls, the EPA proposed that the 2-to-1 

 

289 CAA section 110(c)(1)(A). 

290 The 2-year deadline does not necessarily apply to FIPs following disapproval of a tribal 

implementation plan. 

291 See “Selection of Sequence of Mandatory Sanctions for Findings Made Pursuant to Section 

179 of the Clean Air Act,” 59 FR 39832 (August 4, 1994), codified at 40 CFR 52.31. 
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emission offset requirement will apply for all new sources subject to the nonattainment new 

source review program beginning 18 months following such finding or disapproval unless the 

state corrects the deficiency before that date. The EPA proposed that the highway funding 

restrictions sanction will also apply beginning 24 months following such finding or disapproval 

unless the state corrects the deficiency before that date. Finally, the EPA proposed that the 

provisions in 40 CFR 52.31 regarding staying the sanctions clock and deferring the imposition of 

sanctions would also apply. In this action, the EPA is finalizing the order of sanctions as 

proposed in the February 2013 proposal and finalizing its decision concerning the application of 

40 CFR 52.31. 

Mandatory sanctions under CAA section 179 generally apply only in nonattainment 

areas. By its definition, the emission offset sanction applies only in areas required to have a part 

D NSR program, i.e., areas designated nonattainment. Section 179(b)(1) expressly limits the 

highway funding restriction to nonattainment areas. Additionally, the EPA interprets the section 

179 sanctions to apply only in the area or areas of the state that are subject to or required to have 

in place the deficient SIP and for the pollutant or pollutants that the specific SIP element 

addresses. For example, if the deficient provision applies statewide and applies for all NAAQS 

pollutants, then the mandatory sanctions would apply in all areas designated nonattainment for 

all NAAQS within the state. In this case, the EPA will evaluate the geographic scope of potential 

sanctions at the time it makes a determination that the air agency has failed to make a complete 

SIP submission in response to this SIP call, or at the time it disapproves such a SIP submission. 

The appropriate geographic scope for sanctions may vary depending upon the SIP provisions at 

issue. 

C. SIP Call Timing Under Section 110(k)(5) 
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When the EPA finalizes a finding of substantial inadequacy and a SIP call for any state, 

CAA section 110(k)(5) requires the EPA to establish a SIP submission deadline by which the 

state must make a SIP submission to rectify the identified deficiency. Pursuant to CAA section 

110(k)(5), the EPA has authority to set a SIP submission deadline that is up to 18 months from 

the date of the final finding of inadequacy. 

The EPA proposed to establish a date 18 months from the date of promulgation of the 

final finding for the state to respond to the SIP call. After further evaluation of this issue and 

consideration of comments on the proposed SIP call, the EPA has decided to finalize the 

proposed schedule. Thus, the SIP submission deadline for each of the states subject to this SIP 

call will be November 22, 2016. Thereafter, the EPA will review the adequacy of that new SIP 

submission in accordance with the CAA requirements of sections 110(a), 110(k), 110(l) and 193, 

including the EPA’s interpretation of the CAA reflected in the SSM Policy as clarified and 

updated through this rulemaking. 

The EPA is providing the maximum time permissible under the CAA for a state to 

respond to a SIP call. The EPA believes that it is appropriate to provide states with the full 18 

months authorized under CAA section 110(k)(5) in order to allow states sufficient time to make 

SIP revisions following their own SIP development process. In general, the EPA considers this a 

reasonable time period for the affected states to revise their state regulations, provide for public 

input, process the SIP revision through the state’s own procedures and submit the SIP revision to 

the EPA. Such a schedule will allow for the necessary SIP development process to correct the 

deficiencies, yet still achieve the necessary SIP improvements as expeditiously as practicable. 

There may be exceptions, particularly in states that have adopted especially time-consuming 

procedures for adoption and submission of SIP revisions. The EPA acknowledges that the 
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longstanding existence of many of the provisions at issue, such as automatic exemptions for 

SSM events, may have resulted in undue reliance on them as a compliance mechanism by some 

sources. As a result, development of appropriate SIP revisions may entail reexamination of the 

applicable emission limitations themselves, and this process may require the maximum time 

allowed by the CAA. For example, if circumstances do not allow the state to develop alternative 

emission limitations within that time, the state may find it necessary to remove the automatic 

exemptions in an initial responsive SIP revision and establish alternative emission limitations in 

a later SIP revision. Nevertheless, the EPA encourages the affected states to make the necessary 

revisions in as timely a fashion as possible and encourages the states to work with the respective 

EPA Regional Office as they develop the SIP revisions. The EPA intends to review and act upon 

the SIP submissions as promptly as resources will allow, in order to correct these deficiencies in 

as timely a manner as possible. Recent experience with several states that elected to correct the 

deficiencies identified in the February 2013 proposal in advance of this final action suggests that 

these SIP revisions can be addressed efficiently through cooperation between the air agencies 

and the EPA. 

The EPA notes that the SIP call for affected states finalized in this action is narrow and 

applies only to the specific SIP provisions determined to be inconsistent with the requirements of 

the CAA. To the extent that a state is concerned that elimination of a particular aspect of an 

existing emission limitation, such as an impermissible exemption, will render that emission 

limitation more stringent than the state originally intended and more stringent than needed to 

meet the CAA requirements it was intended to address, the EPA anticipates that the state will 

revise the emission limitation accordingly, but without the impermissible exemption or other 

feature that necessitated the SIP call. With adequate justification, this SIP revision might, e.g., 
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replace a numerical emission limitation with an alternative control method (design, equipment, 

work practice or operational standard) as a component of the emission limitation applicable 

during startup and/or shutdown periods. 

Finally, the EPA notes that its authority under CAA section 110(k)(5) does not extend to 

requiring a state to adopt a particular control measure in its SIP revision in response to the SIP 

call. Under principles of cooperative federalism, the CAA vests air agencies with substantial 

discretion to develop SIP provisions, so long as the provisions meet the legal requirements and 

objectives of the CAA.292 Thus, the inclusion of a SIP call to a state in this action should not be 

misconstrued as a directive to the state to adopt a particular control measure. The EPA is merely 

requiring that affected states make SIP revisions to remove or revise existing SIP provisions that 

fail to comply with fundamental requirements of the CAA. The states retain discretion to remove 

or revise those provisions as they determine best, so long as they bring their SIPs into 

compliance with the requirements of the CAA.293 Through this rulemaking action, the EPA is 

reiterating, clarifying and updating its interpretations of the CAA with respect to SIP provisions 

that apply to emissions from sources during SSM events in order to provide states with 

comprehensive guidance concerning such provisions. 

D. Response to Comments Concerning SIP Call Authority, Process and Timing 

 

292 See Virginia, et al. v. EPA, 108 F.3d 1397 (D.C. Cir. 1997) (SIP call remanded and vacated 

because, inter alia, the EPA had issued a SIP call that required states to adopt a particular control 

measure for mobile sources). 

293 Notwithstanding the latitude states have in developing SIP provisions, the EPA is required to 

assure that states meet the basic legal criteria for SIPs. See Michigan, et al. v. EPA, 213 F.3d 

663, 686 (D.C. Cir. 2000) (upholding NOx SIP call because, inter alia, the EPA was requiring 

states to meet basic legal requirement that SIPs comply with section 110(a)(2)(D), not dictating 

the adoption of a particular control measure). 
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The EPA received a wide range of comments on the February 2013 proposal and the 

SNPR questioning the scope of the Agency’s authority to issue this SIP call action under section 

110(k)(5), the process followed by EPA for this SIP call action, or the timing that the EPA 

provided for response to this SIP call action. Although there were numerous comments on these 

general topics, the majority of the comments raised the same questions and made similar 

arguments (e.g., that the EPA has an obligation under section 110(k)(5) to “prove” not only that 

an exemption for SSM events in a SIP emission limitation is contrary to the explicit legal 

requirements of the CAA but also that this illegal exemption “caused” a specific violation of the 

NAAQS at a particular monitor on a particular day). For clarity and ease of discussion, the EPA 

is responding to these overarching comments grouped by topic. 

1. Comments that section 110(k)(5) requires the EPA to “prove causation” to have authority 

to issue a SIP call. 

Comment: Numerous state and industry commenters argued that the EPA has no 

authority to issue a SIP call with respect to a given SIP provision unless and until the Agency 

first proves definitively that the provision has caused a specific harm, such as a specific violation 

of the NAAQS in a specific area. These commenters generally focused upon the “attainment and 

maintenance” clause of section 110(k)(5) and did not address the “comply with any requirement 

of” the CAA clause. 

For example, many industry commenters opposed the EPA’s interpretation of section 

110(k)(5) on the grounds that the Agency had failed to provide a specific technical analysis 

“proving” how the SIP provisions failed to provide for attainment or maintenance of the 

NAAQS. For areas attaining the NAAQS, commenters asserted that there should be a 

presumption that existing SIP provisions are adequate if they have resulted in attainment of the 
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NAAQS. For areas violating the NAAQS, commenters claimed that the EPA is required to 

conduct a technical analysis to determine if there is a “nexus between the provisions that are the 

subject of its SSM SIP Call Proposal and the specific pollutants for which attainment has not 

been achieved.” Other industry commenters argued that in order to have authority to issue a SIP 

call, the EPA must prove through a technical analysis that a given SIP provision “is” 

substantially inadequate, not that it “may be.” These commenters claimed that the EPA has not 

shown how any of the SIP provisions at issue in this action “threatens the NAAQS, fails to 

sufficiently mitigate interstate transport, or comply with any other CAA requirement.” Many 

industry commenters questioned whether exempt emissions during SSM events pose any 

attainment-related concerns, making assertions such as: “[i]nfrequent malfunction, startup and 

shutdown events at a limited number of stationary sources are likely to have no effect on 

attainment.” 

Many state commenters made similar arguments, based on the specific attainment or 

nonattainment status of areas in their respective states. For example, one state commenter 

claimed that the EPA failed to make required technical findings that the specific provisions the 

Agency identified as legally deficient “are so substantially inadequate that the State cannot attain 

or maintain the NAAQS or otherwise comply with the CAA.” The commenter claimed that the 

EPA should have evaluated all of the state’s emission limitations, emission inventories and 

attainment and maintenance demonstrations for the NAAQS, rather than focusing on these 

individual SIP provisions. In order to demonstrate substantial inadequacy under section 

110(k)(5), the state claimed, the EPA “must point to facts” that show “the State cannot attain or 

maintain the NAAQS or comply with the CAA” if the provisions remain in the SIP. Other states 

made comparable arguments with respect to the SIP provisions at issue in their SIPs and claimed 
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that the EPA is required to establish how the provisions caused or contributed to a specific 

violation of a NAAQS in those states. 

By contrast, many environmental group commenters and individual commenters took the 

opposite position concerning what is necessary to support a finding of substantial inadequacy 

under section 110(k)(5). These commenters argued that that the EPA may issue a SIP call not 

only where it determines that a SIP is substantially inadequate to attain or maintain a NAAQS 

with a technical analysis but also where the Agency determines that the SIP is substantially 

inadequate “to comply with any requirement of the Act.” The commenters noted that the EPA 

identified specific statutory provisions of the CAA with which the SIP provisions at issue in this 

action do not comply. For example, these commenters agreed with the EPA’s view that SIP 

provisions with automatic or discretionary exemptions for emissions during SSM events do not 

meet the fundamental requirements that SIP emission limitations must apply to limit emissions 

from sources on a continuous basis, in accordance with sections 110(a)(2)(A), 110(a)(2)(C) and 

302(k). In addition to arguing that failure to meet legal requirements of the CAA is a sufficient 

basis for a SIP call, some commenters provided additional support to illustrate how SIP 

provisions with deficiencies such as automatic or discretionary exemptions for emissions during 

SSM events result in large amounts of excess emissions that would otherwise be violations of the 

applicable emission limitations. 

Response: The EPA disagrees with the argument that it has no authority to issue a SIP 

call under section 110(k)(5) unless the Agency provides a factual or technical analysis to 

demonstrate that the SIP provision at issue caused a specific environmental harm or undermined 

a specific enforcement case. As explained in the February 2013 proposal, in the SNPR and in this 

final action, the EPA interprets its authority under section 110(k)(5) to authorize a SIP call for 
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not only provisions that are substantially inadequate for purposes of attainment or maintenance 

of the NAAQS but also those provisions that are substantially inadequate for purposes of “any 

requirement” of the CAA.294 To be clear, the EPA can also issue a SIP call whenever it 

determines that a SIP as a whole, or a specific SIP provision, is deficient because the SIP did not 

prevent specific violations of a NAAQS, at a specific monitor, on a specific date. However, that 

is not the extent of the EPA’s authority under section 110(k)(5). 

On its face, section 110(k)(5) does not impose any explicit requirements with respect to 

what specific form of factual or analytical basis is necessary for issuance of a SIP call. Because 

the statute does not prescribe the basis on which the EPA is to make a finding of substantial 

inadequacy, the Agency interprets section 110(k)(5) to provide discretion concerning what is 

necessary to support such a finding. The Agency believes that the nature of the factual or 

analytical basis necessary to make a finding is dependent upon the specific nature of the 

substantial inadequacy in a given SIP provision. 

For example, when the EPA issued the NOx SIP Call to multiple states because their SIPs 

failed to address interstate transport adequately in accordance with section 110(a)(2)(D)(i)(I), the 

Agency did base that SIP call on a detailed factual analysis including ambient air impacts.295 In 

that situation, the specific requirement of the CAA at issue was the statutory obligation of each 

state to have a SIP that contains adequate provisions to prohibit emissions from sources “in 

amounts” that “contribute significantly to nonattainment in, or interfere with maintenance by, 

 

294 See February 2013 proposal, 78 FR 12459 at 12483–89 (February 22, 2013); SNPR, 79 FR 

55919 at 55935. 

295 See “Finding of Significant Contribution and Rulemaking for Certain States in the Ozone 

Transport Assessment Group Region for Purposes of Reducing Regional Transport of Ozone,” 

63 FR 57356 (October 27, 1998). 
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any other State” with respect to the NAAQS. Because of the phrase “in amounts,” the EPA 

considered it appropriate to evaluate whether each state’s SIP was substantially inadequate to 

comply with section 110(a)(2)(D)(i)(I) through a detailed analysis of the emissions from the state 

and their impacts on other states. Moreover, given the use of ambiguous terms in section 

110(a)(2)(D)(i)(I) such as “contribute significantly,” the EPA concluded that it was appropriate 

to conduct a detailed analysis to quantify the amount of emissions that each of the affected states 

needed to eliminate in order to comply with section 110(a)(2)(D)(i)(I) for the specific NAAQS in 

question. However, the EPA’s decision to determine these facts and to conduct these analyses as 

a basis for that particular SIP call action was due to the nature of the SIP deficiency at issue and 

the wording of section 110(a)(2)(D)(i)(I). The EPA has similarly issued other SIP calls for which 

the Agency determined that a specific factual or technical analysis was appropriate to support the 

finding of substantial inadequacy.296 

Not all situations, however, require the same type of detailed factual analysis to support 

the finding of substantial inadequacy. For example, when the EPA issued the PSD GHG SIP call 

to 13 states for failure to have a PSD permitting program that properly addresses GHG 

emissions, the Agency did not need to base that SIP call action on a detailed factual analysis of 

ambient air impacts.297 In that situation, the statutory requirement of the CAA in question was 

 

296 See, e.g., “Finding of Substantial Inadequacy of Implementation Plan; Call for Iowa State 

Implementation Plan Revision,” 76 FR 41424 (July 14, 2011) (SIP call to Iowa due to PM2.5

NAAQS violations in Muscatine area); “Approval and Promulgation of State Implementation 

Plans; Call for Sulfur Dioxide SIP Revisions for Billings/Laurel, MT,” 58 FR 41430 (August 4, 

1993) (SIP call to Montana due to modeled violations of the SO2 NAAQS). 

297 See “Action to Ensure Authority to Issue Permits Under the Prevention of Significant 

Deterioration Program to Sources of Greenhouse Gas Emissions; Finding of Substantial 

Inadequacy and SIP Call,” 75 FR 77698 (December 13, 2010). The EPA notes that a number of 

petitioners challenged this SIP call on various grounds, but the court ultimately determined that 

they did not have standing. Texas, et al. v. EPA, 726 F.3d 180 (D.C. Cir. 2013). 
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the obligation of each state SIP under section 110(a)(2)(C) to include a PSD permitting program 

that addresses all federally regulated air pollutants, including GHGs. In that action, the EPA 

made a finding that the SIPs of 13 states were substantially inadequate to “comply with any 

requirement” of the CAA because the PSD permitting programs in their EPA-approved SIPs did 

not apply to GHG emissions from new and modified sources. Accordingly, the EPA issued a SIP 

call to the 13 states because their SIPs failed to comply with specific legal requirements of the 

CAA. This failure to meet an explicit CAA legal requirement to address GHG emissions in 

permits for sources as required by statute did not require the EPA to provide a technical analysis 

of the specific environmental impacts that this substantial inadequacy would cause. For this type 

of SIP deficiency, it was sufficient for the EPA to make a factual finding that the affected states 

had SIPs that failed to meet this fundamental legal requirement.298 The EPA has issued other SIP 

calls for which the Agency made a finding that a state’s failure to meet specific legal requirement 

of the CAA for SIPs was a substantial inadequacy without the need to provide a technical air 

quality analysis relating to NAAQS violations.299 

 

298 Id., 75 FR 77698 at 77705-07. 

299 See, e.g., “Finding of Substantial Inadequacy of Implementation Plan; Call for California 

State Implementation Plan Revision,” 68 FR 37746 (June 25, 2003) (SIP call to California for 

failure to meet legal requirements of section 110(a)(2)(C), section 110(a)(2)(I), and section 

110(a)(2)(E) because of exemptions for agricultural sources from NNSR and PSD permitting 

requirements); “Credible Evidence Revisions,” 62 FR 8314 at 8327 (February 24, 1997) 

(discussing SIP calls requiring states to revise their SIPs to meet CAA requirements with respect 

to the use of any credible evidence in enforcement actions for SIP violations). 
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The EPA believes that the most relevant precedent for what is necessary to support a 

finding of substantial inadequacy in this action is the SIP call that the Agency previously issued 

to the state of Utah for deficient SIP provisions related to the treatment of excess emissions 

during SSM events.300 In that SIP call action, the EPA made a finding that two specific 

provisions in the state’s SIP were substantially inadequate because they were inconsistent with 

legal requirements of the CAA. For one of the provisions that included an exemption for 

emissions during “upsets” (i.e., malfunctions), the EPA explained: 

“Contrary to CAA section 302(k)’s definition of emission limitation, the 

exemption [in the provision] renders emission limitations in the Utah SIP less 

than continuous and, contrary to the requirements of CAA sections 110(a)(2)(A) 

and (C), undermines the ability to ensure compliance with SIP emissions 

limitations relied on to achieve the NAAQS and other relevant CAA requirements 

at all times. Therefore, the [provision] renders the Utah SIP substantially 

inadequate to attain or maintain the NAAQS or to comply with other CAA 

requirements such as CAA sections 110(a)(2)(A) and (C) and 302(k), CAA 

provisions related to prevention of significant deterioration (PSD) and 

nonattainment NSR permits (sections 165 and 173), and provisions related to 

protection of visibility (section 169A).”301 

For a second provision, the EPA made a finding of substantial inadequacy because the 

provision interfered with the enforcement structure of the CAA. The EPA explained: 

 

300 See “Finding of Substantial Inadequacy of Implementation Plan; Call for Utah State 

Implementation Plan Revision; Proposed rule,” 76 FR 21639 (April 18, 2011). 

301 Id., 76 FR 21639 at 21641. The EPA also found the first provision substantially inadequate 

because it operated to create an additional exemption for emissions during malfunctions that 

modified the existing emission limitations in some federal NSPS and NESHAP that the state had 

incorporated by reference into its SIP. The EPA’s 1999 SSM Guidance had indicated that state 

SIP provisions could not validly alter NSPS or NESHAP. 
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“This provision appears to give the executive secretary exclusive authority to 

determine whether excess emissions constitute a violation and thus to preclude 

independent enforcement action by EPA and citizens when the executive 

secretary makes a non-violation determination. This is inconsistent with the 

enforcement structure under the CAA, which provides enforcement authority not 

only to the States, but also to EPA and citizens. . . . Because it undermines the 

envisioned enforcement structure, it also undermines the ability of the State to 

attain and maintain the NAAQS and to comply with other CAA requirements 

related to PSD, visibility, NSPS, and NESHAPS.”302 

In the Utah SIP call rulemaking, the EPA received similar adverse comments arguing that 

the Agency has no authority under section 110(k)(5) to issue a SIP call without a factual analysis 

that proves that the deficient SIP provisions caused a specific environmental harm, such as a 

NAAQS violation. Commenters in that rulemaking likewise argued that the EPA was required to 

prove a causal connection between the excess emissions that occurred during a specific exempt 

malfunction and a specific violation of the NAAQS. In response to those comments, the EPA 

explained: 

“[W]e need not show a direct causal link between any specific unavoidable 

breakdown excess emissions and violations of the NAAQS to conclude that the 

SIP is substantially inadequate. It is our interpretation that the fundamental 

integrity of the CAA’s SIP process and structure is undermined if emission limits 

relied on to meet CAA requirements can be exceeded without potential recourse 

by any entity granted enforcement authority by the CAA. We are not restricted to 

issuing SIP calls only after a violation of the NAAQS has occurred or only where 

a specific violation can be linked to a specific excess emissions event.”303 

The EPA’s interpretation of section 110(k)(5) in the Utah action was directly challenged 

in US Magnesium v. EPA.

304 Among other claims, the petitioners argued that the EPA did not 

have authority for the SIP call because the Agency had not “set out facts showing that the [SIP 

provision] has prevented Utah from attaining or maintaining the NAAQS or otherwise 

 

302 Id. 303 Id., 76 FR 21639 at 21643. 

304 690 F.3d 1157 (10th Cir. 2012). 
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complying with the CAA.” Thus, the same arguments raised by commenters in this action have 

previously been advanced and rejected by the EPA and the courts. The court expressly upheld 

the EPA’s interpretation of section 110(k)(5), concluding: 

“Certainly, a SIP could be deemed substantially inadequate because air-quality 

records showed that actions permitted under the SIP resulted in NAAQS 

violations, but the statute can likewise apply to a situation like this, where the 

EPA determines that a SIP is no longer consistent with the EPA’s understanding 

of the CAA. In such a case, the CAA permits the EPA to find that a SIP is 

substantially inadequate to comply with the CAA, which would allow the EPA to 

issue a SIP call under CAA section 110(k)(5).”305 

Finally, the EPA disagrees with the commenters on this specific point because it is not a 

logical construction of section 110(k)(5). The implication of the commenters’ argument is that if 

a given area is in attainment, then the question of whether the SIP provisions meet applicable 

legal requirements is irrelevant. If a given area is not in attainment, then the implication of the 

commenter’s argument is that the EPA must prove that the legally deficient SIP provision 

factually caused the violation of the NAAQS or else the legal deficiency is irrelevant. In the 

latter case, the logical extension of the commenter’s argument is that no matter how deficient a 

SIP provision is to meet applicable legal requirements, the EPA is foreclosed from directing the 

state to correct that deficiency unless and until there is proof of a specific environmental harm 

caused, or specific enforcement case thwarted, by that deficiency. Such a reading is inconsistent 

with both the letter and the intent of section 110(k)(5). 

2. Comments that the EPA must make specific factual findings to meet the requirements of 

section 110(a)(2)(H)(ii) to have authority to issue a SIP call. 

 

305 Id. 690 F.3d at 1168. 
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Comment: A number of commenters argued that even if section 110(k)(5) does not 

require the EPA to provide a technical analysis to support a finding of substantial inadequacy, 

section 110(a)(2)(H)(ii) does impose this obligation. The commenters noted that section 

110(a)(2)(H)(ii) requires states to revise their SIPs “whenever the Administrator finds on the 

basis of information available to the Administrator that the plan is substantially inadequate.” The 

commenters claimed that this statutory language imposes a requirement for the EPA to “find” the 

SIP inadequate and “clearly indicates that a SIP Call must be justified by factual findings 

supported by record evidence.” 

One commenter argued that the use of the word “finds” should be read in light of the 

dictionary definition of “find”—”to discover by study or experiment.” The commenter noted that 

courts commonly hold that agencies must draw a link between the facts and a challenged agency 

decision. To support this basic principle of administrative law, the commenter cited a litany of 

cases including: Motor Vehicle Mfrs Ass’n v. State Farm Mut Auto Ins. Co., 463 U.S. 29. 43 

(1983); Appalachian Power Co. v EPA, 251 F.3d 1026, 1034 (D.C. Cir. 2001); Tex Tin Corp. v. 

EPA, 992 F.2d 353, 356 (D.C. Cir. 1993); Nat’l Gypsum v. EPA, 968 F.2d 40, 43-44 (D.C. Cir. 

1992); Michigan v. EPA, 213 F.3d 663, 681 (D.C. Cir. 2000) Thus, the commenter suggested 

that the statutory language of section 110(a)(2)(H)(ii) requires a specific factual or technical 

demonstration concerning the ambient air impacts of an inadequate SIP provision, even if the 

language of section 110(k)(5) does not. 

Another commenter argued that the phrase “on the basis of information available to the 

Administrator” in section 110(a)(2)(H)(ii) means that the EPA must not only consider the 

specific terms of the SIP provisions relative to the legal requirements of the statute but must also 

consider other information that is “available,” including how the provisions have been affecting 
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air quality or enforcement since approval. In support of this proposition, the commenter cited 

1970 legislative history for section 110(a)(2)(H): 

Whenever the Secretary or his representative finds from new information 

developed after the plan is approved that the plan is not or will not be adequate to 

achieve promulgated ambient air quality standards he must notify the appropriate 

States and give them an opportunity to respond to the new information.306 

Thus, the commenter concluded that the EPA must not only find that the SIP is facially 

inconsistent with the legal requirements of the CAA but also find it “substantially inadequate” to 

achieve the goals of the requirements as a factual matter before issuing a SIP call. The 

implication of the commenter’s argument is that section 110(a)(2)(H)(ii) imposes additional 

limitations upon the EPA’s authority to issue a SIP call. 

Response: The EPA disagrees that it has not made the findings necessary to support the 

present SIP call action. The thrust of the commenters’ argument is that the facts that the EPA 

“finds” or the “information” upon which the EPA bases such a finding can only be technical or 

scientific facts proving that a given SIP provision resulted in emissions that caused a specific 

violation of the NAAQS. As with section 110(k)(5), however, nothing in section 110(a)(2)(H)(ii) 

compels such a narrow reading. The plain language of section 110(a)(2)(H)(ii) does not support 

the commenters’ arguments. To the extent that section 110(a)(2)(H)(ii) is ambiguous, however, 

the EPA does not interpret it to require the types of technical findings claimed by the 

commenters in the case of SIP provisions that do not meet legal requirements of the CAA. To the 

contrary, the EPA interprets the statutory language to leave to the Agency’s discretion what facts 

or information are necessary to find that a given SIP provision is substantially inadequate. In 

short, the EPA’s “finding” may be a finding that a SIP provision does not meet applicable legal 

 

306 See S. Rep No. 91-1196 at 55-56 (1970). 
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requirements without definitive proof that this legal deficiency caused a specific outcome, such 

as a specific impact on the NAAQS or a specific enforcement action. 

First, section 110(a)(2)(H)(ii) does not on its face directly address the scope of the EPA’s 

authority, unlike section 110(k)(5). Section 110(a)(2)(H)(ii) appears in section 110(a)(2), which 

contains a listing of specific structural or program requirements that each state’s SIP must 

include. In the case of section 110(a)(2)(H)(ii), the CAA requires each state to have provisions in 

its SIP that “provide for revision of such plan” in the event that the EPA issues a SIP call. Given 

that section 110(k)(5) is the provision that directly addresses the EPA’s authority to issue a SIP 

call, section 110(a)(2)(H)(ii) should not be interpreted in a way that contradicts or curtails the 

broad authority provided in section 110(k)(5). As described in response to comments, the EPA 

does not interpret section 110(k)(5) to require proof that a given SIP provision caused a specific 

environmental harm or undermined a specific enforcement action in order to find the provision 

substantially inadequate. If the provision fails to meet fundamental legal requirements of the 

CAA for SIP provisions, that alone is sufficient. 

Second, even if read in isolation, section 110(a)(2)(H)(ii) does not specify what type of 

finding the EPA is required to make or specify the way in which the Agency should make such a 

finding. The EPA agrees that this section of the CAA describes findings that the EPA makes “on 

the basis of information available to the Administrator that the plan is substantially inadequate to 

attain” the NAAQS. This section does not, however, expressly state that the “information” in 

question must be a particular form of information, nor does it expressly require any specified 

form of technical analysis such as modeling that demonstrates that a particular SIP deficiency 

caused a violation of the NAAQS. Because the term “information” is not limited in this way, the 

EPA interprets it to mean whatever form of information is relevant to the finding in question. For 
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certain types of deficiencies, the EPA may determine that such a technical analysis is 

appropriate, but that does not mean that it is required as a basis for all findings of substantial 

inadequacy. 307 

Third, section 110(a)(2)(H)(ii), like section 110(k)(5), is not limited to findings related 

exclusively to attainment of the NAAQS. Section 110(a)(2)(H)(ii) also expressly refers to 

findings by the EPA that a SIP is substantially inadequate “to otherwise comply with any 

additional requirements established under” the CAA. The EPA interprets this explicit reference 

to “any additional requirements” to include any legal requirements applicable to SIP provisions, 

such as the requirement that emission limitations must apply continuously. The commenters 

misconstrue section 110(a)(2)(H)(ii) to refer exclusively to provisions that are literally found to 

cause a specific violation of the NAAQS. The EPA acknowledges that the legislative history 

quoted by the commenters discusses findings related to a failure of a SIP to attain the NAAQS, 

but the passage quoted does not explain the meaning of “new information” any more specifically 

than the statute, nor does the passage explain why the actual statutory text of section 

 

307 See, e.g., “Finding of Significant Contribution and Rulemaking for Certain States in the 

Ozone Transport Assessment Group Region for Purposes of Reducing Regional Transport of 

Ozone; Final rule,” 63 FR 57355 (October 27, 1998) (EPA found that the SIPs of multiple states 

did not adequately control emissions that resulted in significant contribution to nonattainment in 

other states); “Action To Ensure Authority To Issue Permits Under the Prevention of Significant 

Deterioration Program to Sources of Greenhouse Gas Emissions: Finding of Substantial 

Inadequacy and SIP Call; Final rule,” 75 FR 77697 (December 13, 2010) (EPA found that the 

SIPs of multiple states did not meet the legal requirements for PSD permitting for GHG 

emissions). 
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110(a)(2)(H)(ii) now refers to findings related to failures to meet “any additional requirements” 

of the CAA.308 Moreover, the commenters did not address the changes to the CAA in 1977 that 

added to the statutory language to refer to other requirements, nor did they address the changes 

to the CAA in 1990 that added section 110(k)(5), which refers to all other requirements of the 

CAA. The EPA believes that the more recent changes to the statute in fact support its view that 

section 110(a)(2)(H)(ii) entails compliance with the legal requirements of the CAA, not the 

narrow reading advocated by the commenters. 

Fourth, the EPA disagrees with the commenters’ arguments that it did not make factual 

“findings” to support this SIP call. To the contrary, the EPA has made numerous factual 

determinations with regard to the specific SIP provisions at issue. For example, for those SIP 

provisions that include automatic exemptions for emissions during SSM events, the EPA has 

found that the provisions are inconsistent with the definition of “emission limitation” in section 

302(k) and that SIP provisions that allow sources to exceed otherwise applicable emission 

limitations during SSM events may interfere with attainment and maintenance of the NAAQS. 

The EPA has also made the factual determination that other SIP provisions that authorize 

director’s discretion exemptions during SSM events are inconsistent with the statutory provisions 

applicable to the approval and revision of SIP provisions. The EPA has found that overbroad 

enforcement discretion provisions are inconsistent with the enforcement structure of the CAA in 

that they could be interpreted to allow the state to make the final decision whether such 

 

308 The EPA notes that the significance of this 1970 legislative history was raised in US 

Magnesium, LLC v. EPA, 690 F.3d 1157, 1166 (10th Cir. 2012). That court found the legislative 

history “inapposite” simply because it did not pertain to section 110(k)(5) which Congress added 

to the CAA in 1990. This legislative history passage is of limited significance in this action as 

well. 
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emissions are violations, thus impeding the ability of the EPA and citizens to enforce the 

emission limitations of the SIP. Similarly, the EPA has found, consistent with the court’s 

decision in NRDC v. EPA, that affirmative defenses in SIP provisions are inconsistent with CAA 

requirements because they operate to alter or eliminate the jurisdiction of the courts to determine 

liability and impose penalties. In short, the EPA has made the factual findings that specific 

provisions are substantially inadequate to meet requirements of the CAA, as contemplated in 

both section 110(a)(2)(H)(ii) and section 110(k)(5). 

Finally, the EPA notes that the cases cited by the commenters to support their contentions 

concerning the factual basis for agency decisions are not relevant to the specific question at hand. 

The correct question is whether section 110(a)(2)(H)(ii) requires the type of factual or technical 

analysis that they claim. None of the cases they cited address this specific issue. By contrast, the 

decision of the Tenth Circuit in US Magnesium, LLC v. EPA is much more relevant. In that 

decision, the court concluded that the EPA’s authority under section 110(k)(5) is not restricted to 

situations where a deficient SIP provision caused a specific violation of the NAAQS and the 

exercise of that authority does not require specific factual findings that the provision caused such 

impacts.309 

3. Comments that the EPA lacks authority to issue a SIP call because it is interpreting the 

term “substantial inadequacy” incorrectly. 

Comment: Some commenters claimed that although the term “substantially inadequate” is 

not defined in the statute, the EPA made no effort to interpret the term. Citing Qwest Corp. v. 

 

309 Id., 690 F.3d 1157, 1166. 
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FCC, 258 F.3d 1191, 1201-02 (10th Cir. 2001), the commenters argued that the EPA is not 

entitled to any deference to its interpretation of the term “substantial inadequacy.” 

Other commenters acknowledged that the EPA took the position that the term 

“substantially inadequate” is not defined in the CAA and that the Agency can establish an 

interpretation of that provision under Chevron 2. However, these commenters disagreed that the 

EPA’s interpretation of the term in the February 2013 proposal was reasonable. In particular, the 

commenters disagreed with the EPA’s view that once a SIP provision is found to be “facially 

inconsistent” with a specific legal requirement of the CAA, nothing more is required to find the 

provision “substantially inadequate” to “comply with” that requirement. Commenters claimed 

that the EPA’s interpretation conflicts with the statute because it ignores the statutory 

requirement that a SIP call be based on inadequacies that are “substantial” and that the 

interpretation does not meet the “high bar” Congress established before states could be required 

to undertake the difficult task of revising a SIP. 

State commenters claimed that the requirement that the EPA must determine that the SIP 

is “substantially” inadequate establishes a heavy burden for the EPA. The commenters relied on 

a dictionary definition of “substantially” as meaning “considerable in importance, value, degree, 

amount, or extent.” The commenters argued that when modifying the word “inadequate,” the use 

of the modifier “substantially” in section 110(k)(5) enhances the degree of proof required. Thus, 

the commenters argued that the EPA cannot just assume that the provisions may prevent 

attainment of the NAAQS. 

Other industry commenters disagreed that the term “substantially inadequate” is 

ambiguous but claimed that even if it were, the EPA’s own interpretation is vague and 

ambiguous. The commenters asserted that the EPA’s statement that it must evaluate the 
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adequacy of specific SIP provision “in light of the specific purposes for which the SIP provision 

at issue is required” and with respect to whether the provision meets “fundamental legal 

requirements applicable to such a provision” is not a reasonable interpretation of the statutory 

language. Furthermore, the commenters argued, the EPA’s interpretation of section 110(k)(5) to 

authorize a SIP call in the absence of any causal evidence that the SIP provision at issue causes a 

particular environmental impact reads out of the statute “the explicit requirement that a SIP call 

related to NAAQS be made only where the state plan is substantially inadequate to attain or 

maintain the relevant standard.” 

Response: The EPA disagrees with commenters who claimed that the Agency did not 

explain its interpretation of section 110(k)(5) in general, or the term “substantially inadequate” in 

particular, in the February 2013 proposal. To the contrary, the EPA provided an explanation of 

why it considers section 110(k)(5) to be ambiguous and provided a detailed explanation of how 

the Agency is interpreting and applying that statutory language to the specific SIP provisions at 

issue in this action.310 Moreover, the EPA explained why it believes that the four major types of 

provisions at issue are inconsistent with applicable legal requirements of the CAA and thus 

substantially inadequate. In the SNPR, the EPA reiterated its interpretation of section 110(k)(5) 

with respect to affirmative defense provisions in SIPs but updated that interpretation in response 

to the logic of the more recent court decision in NRDC v. EPA. Thus, the commenters’ reliance 

on the Qwest decision is not appropriate, because the EPA did explain its interpretation of the 

statute and it is not one that is contrary to the statute. A more appropriate precedent is the 

decision in US Magnesium LLC v. EPA, in which the same court upheld the EPA’s interpretation 

 

310 See February 2013 proposal, 78 FR 12459 at 12483–88. 
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of its authority under section 110(k)(5). In short, the EPA believes that section 110(k)(5) 

provides the EPA with discretion to determine what constitutes a substantial inadequacy and to 

determine the appropriate basis for such a finding in light of the relevant CAA requirements at 

issue. Thus, the commenters are in error that the EPA did not articulate its interpretation of 

section 110(k)(5). 

The EPA also disagrees with those commenters who argued that the Agency has ignored 

or misinterpreted the term “substantial” in this action. As many commenters acknowledged, this 

term is not defined in the statute. Their reliance on a dictionary definition, however, is based on 

the incorrect premise that a failure to comply with the legal requirements of the CAA for SIP 

provisions is not “considerable in importance, value, degree, amount, or extent.” 

First, the commenters’ argument ignores the full statutory language of section 110(k)(5) 

in which the EPA is authorized to issue a SIP call whenever it determines that a given SIP 

provision is inadequate, not only because of impacts on attainment of the NAAQS but also upon 

a failure to meet “any other requirement” of the CAA. As explained in the February 2013 

proposal and in the SNPR, the EPA interprets its authority under section 110(k)(5) to encompass 

any type of deficiency, including failure to meet specific legal requirements of the CAA for SIP 

provisions. Failure to comply with these legal requirements can have the effect of interfering 

with attainment and maintenance of the NAAQS (e.g., by allowing unlimited emissions from 

sources during SSM events), but the failure to comply with the legal requirements is in and of 

itself a basis for a SIP call. 

Second, the commenters’ argument implies that failure of a SIP provision to meet a legal 

requirement of the CAA is not a “substantial” inadequacy. The EPA strongly disagrees with the 

view that complying with applicable legal requirements is not an important consideration in 
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general, and not important with respect to the specific legal defects at issue here. For example, 

the EPA considers a SIP provision that does not apply continuously because it contains SSM 

exemptions to be substantially inadequate because it fails to meet legal requirements of sections 

110(a)(2)(A), 110(a)(2)(C) and 302(k). In particular, failure to meet the legal requirements for an 

emission limitation as contemplated in section 302(k) is a “substantial” inadequacy. The EPA is 

not alone in this view; the D.C. Circuit in the Sierra Club v. Johnson case held that emission 

limitations must be continuous and cannot contain SSM exemptions. If inclusion of SSM 

exemptions in emission limitations were not a “substantial” deficiency from the court’s 

perspective, presumably the court would have ruled differently. As another example, the EPA 

considers the inclusion of affirmative defenses in SIP provisions that operate to alter the 

jurisdiction of the courts to be a substantial inadequacy. Again, the EPA’s view that SIP 

provisions cannot interfere with the enforcement structure of the CAA set forth in section 113 

and section 304 is not unreasonable. The court’s decision in NRDC v. EPA held that EPA 

regulations cannot alter or eliminate the jurisdiction of courts to determine liability and impose 

remedies in judicial enforcement cases and this same logic extends to the states in SIP 

provisions. Contrary to the arguments of the commenters, the EPA reasonably interprets the term 

“substantial” in section 110(k)(5) to include compliance with the legal requirements of the CAA 

applicable to SIP provisions. 

Third, the EPA notes that its reading of section 110(k)(5) does not “read out of the 

statute” the statutory language that SIP provisions can be substantially inadequate “to attain or 

maintain the relevant NAAQS” as claimed by the commenters. The EPA agrees that SIP 

provisions can be found substantially inadequate for this specific reason, but it is the commenters 

who read words out of section 110(k)(5) by disregarding the portion of the statute that also 
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authorizes a SIP call whenever a SIP provision does not “comply with any requirement of” the 

CAA. Indeed, the EPA believes that SIP provisions that fail to meet the specific legal 

requirements of the CAA are very likely to have these impacts as well; e.g., the unlimited 

emissions authorized by SSM exemptions can interfere with attainment and maintenance of the 

NAAQS. The EPA believes that Congress consciously included these fundamental legal 

requirements in order to assure that SIP provisions will achieve the objectives of the CAA, such 

as attainment and maintenance of the NAAQS. For example, legislative history for section 

302(k) indicates that Congress intentionally required that emission limitations apply 

continuously in order to assure that they would achieve these goals as well as be consistent with 

the enforcement structure of the CAA.311 

4. Comments that the EPA lacks authority to issue a SIP call because it is required to 

“quantify” the magnitude of any alleged SIP deficiency in order to establish that it is substantial. 

Comment: A number of commenters argued that, in addition to failing to provide a 

required technical analysis to support a SIP call, the EPA was also failing to quantify in advance 

the degree of inadequacy that is necessary for a given SIP provision to be substantially 

inadequate. The commenters asserted that the EPA has a burden to define in advance what 

amount of inadequacy is “substantial,” before the Agency can require states to comply with a SIP 

 

311 See, e.g., H.R. 95-294, at 92 (1977) (referring to emission limitations as a fundamental tool 

for assuring attainment and maintenance of the NAAQS and stating that unless they are 

“complied with at all times, there can be no assurance that ambient standards will be attainment 

and maintained.” 
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call. Some commenters made this argument based upon their experience with prior SIP call 

rulemakings, such as the NOx SIP call in which the Agency performed such an analysis. Other 

commenters, however, evidently based this argument upon their reading of the D.C. Circuit’s 

decision in EME Homer City Generation, L.P. v. EPA.312 Some commenters also argued that 

“all” past EPA SIP calls have been based upon a specific technical analysis concerning the 

sufficiency of a SIP to provide for attainment and maintenance of a NAAQS and that this 

establishes that such an analysis is always required. 

Response: The EPA disagrees that section 110(k)(5) requires the Agency to “quantify” 

the degree of inadequacy in a given SIP provision before issuing a SIP call. As explained in 

detail in the February 2013 proposal and this notice, the EPA interprets section 110(k)(5) to 

authorize the Agency to determine the nature of the analysis necessary to make a finding that a 

SIP provision is substantially inadequate. The EPA agrees that for certain SIP call actions, such 

as the NOx SIP call, the specific nature of the SIP call in question for section 110(a)(2)(D)(i) did 

warrant a technical evaluation of whether the emissions from sources in particular states were 

significantly contributing to violations of a NAAQS in other states. Thus, the EPA elected to 

perform a specific form of analysis to determine whether emissions from sources in certain states 

significantly contributed to violations of the NAAQS in other states, and if so, what degree of 

reductions were necessary to remedy that interstate transport. 

The nature of the SIP deficiencies at issue in this action does not require that type of 

technical analysis and does not require a “quantification” of the extent of the deficiency. In this 

action, the EPA is promulgating a SIP call action that directs the affected states to revise existing 

 

312 696 F.3d 7, 29 (D.C. Cir. 2012) rev’d, 134 S. Ct. 1584 (2014). 
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SIP provisions with specific legal deficiencies that make the provisions inconsistent with 

fundamental legal requirements of the CAA for SIPs, e.g., automatic exemptions for emissions 

during SSM events or affirmative defense provisions that limit or eliminate the jurisdiction of 

courts to determine liability and impose remedies for violations. Accordingly, the EPA has 

determined that it is not necessary to establish that these deficiencies literally caused a specific 

violation of the NAAQS on a particular day or undermined a specific enforcement case. It is 

sufficient that the provisions fail to meet a legal requirement of the CAA and thus are 

substantially inadequate as provided in section 110(k)(5). 

5. Comments that the EPA’s interpretation of substantial inadequacy would override state 

discretion in development of SIP provisions. 

Comment: Some state and industry commenters argued that the EPA’s interpretation of 

its authority under section 110(k)(5) is wrong because it is inconsistent with the principle of 

cooperative federalism. These commenters asserted that the EPA’s interpretation of the term 

“substantially inadequate,” as explained in the February 2013 proposal, would allow the Agency 

to dictate that states revise their SIPs without any consideration of whether the states’ preferred 

control measures affect attainment of the NAAQS, thereby expanding the EPA’s role in CAA 

implementation. Consequently, these commenters concluded, the EPA’s interpretation of section 

110(k)(5) is neither “reasonable” nor “a permissible construction of the statute” under the 

principles of Chevron deference.313 

Response: The EPA disagrees with these commenters because it disagrees with their view 

of the cooperative-federalism relationship established in the CAA, as explained in detail in 

 

313 Chevron, U.S.A., Inc. v. Natural Res. Def. Council, Inc., 467 U.S. 837, 843–44 (1984). 
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section V.D.2 of this document. Because the commenters are misconstruing the respective 

responsibility and authorities of the states and the EPA under cooperative federalism, the Agency 

does not agree that its interpretation of section 110(k)(5) is “unreasonable” for this reason under 

the principles of Chevron. As explained in detail in the February 2013 proposal, the EPA 

interprets its authority under section 110(k)(5) to include the ability to require states to revise 

their SIP provisions to correct the types of deficiencies at issue in this action. 

Section 110(k)(5) explicitly authorizes the EPA to issue a SIP call for a broad range of 

reasons, including to address any SIP provisions that relate to attainment and maintenance of the 

NAAQS, to interstate transport, or to any other requirement of the CAA.314 The EPA’s authority 

and responsibility to review SIP submissions in the first instance is to assure that they meet all 

applicable procedural and substantive requirements of the CAA, in accordance with the 

requirements of sections 110(k)(3), 110(l) and 193. The EPA’s authority and responsibility under 

the CAA includes assuring that SIP provisions comply with specific statutory requirements, such 

as the requirement that emission limitations apply to sources continuously. The CAA imposes 

these statutory requirements in order to assure that the larger objectives of SIPs are achieved, 

such as the attainment and maintenance of the NAAQS, protection of PSD increments, 

improvement of visibility and providing for effective enforcement. The CAA imposes this 

authority and responsibility upon the EPA when it first evaluates a SIP submission for approval. 

Likewise, after the initial approval, section 110(k)(5) authorizes the EPA to require states to 

 

314 See, e.g., US Magnesium, LLC v. EPA, 690 F.3d 1157, 1168 (10th Cir. 2012) (citing 42 

U.S.C. 7410(k)(5)) (holding that the EPA may issue a SIP call not only based on NAAQS 

violations, but also whenever “EPA determines that a SIP is no longer consistent with the EPA’s 

understanding of the CAA”); id. at 1170 (upholding the EPA’s authority “to call a SIP in order to 

clarify language in the SIP that could be read to violate the CAA,” even absent a pertinent 

judicial finding). 
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revise their SIPs whenever the Agency later determines that to be necessary to meet CAA 

requirements. This does not in any way allow the EPA to interfere in the states’ selection of the 

control measures they elect to impose to satisfy CAA requirements relating to NAAQS 

attainment and maintenance, provided that those selected measures comply with all CAA 

requirements such as the need for continuous emissions limitations. Accordingly, the EPA does 

not believe that its interpretation of section 110(k)(5) is at odds with the principles of cooperative 

federalism but rather believes that its interpretation is fully consistent with the letter and the 

purpose of those principles. 

6. Comments that the EPA cannot issue a SIP call for an existing SIP provision unless the 

provision was deficient at the time the state originally developed and submitted the provision for 

EPA approval. 

Comment: Commenters argued that the EPA is using the SIP call to require states to 

change SIP provisions that were acceptable at the time they were originally approved and argued 

that section 110(k)(5) cannot be used for that purpose. Specifically, one commenter asserted that 

section 110(k)(5) provides that findings of substantial inadequacy shall “subject the State to the 

requirements of this chapter to which the State was subject when it developed and submitted the 

plan for which such finding was made.” (Emphasis added by commenter.) The implication of the 

commenters’ argument is that a SIP provision only needs to meet the requirements of the CAA 

that were applicable at the time the state originally developed and submitted the provision for 

EPA approval. Because the EPA has no authority to issue a SIP call under their preferred reading 

of section 110(k)(5), the commenters claimed, the EPA would have to use its authority under 

section 110(k)(6) and would have to establish that the original approval of each of the provisions 

at issue in this action was in error. 
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Response: The EPA disagrees with this reading of section 110(k)(5). As an initial matter, 

the commenter takes the quoted excerpt of the statute out of context. The quoted language 

follows “to the extent the Administrator deems appropriate.” Thus it is clear when the statutory 

provision is read in full that the EPA has discretion in specifying the requirements to which the 

state is subject and is not limited to specifying only those requirements that applied at the time 

the SIP was originally “developed and submitted.” Moreover, this cramped reading of section 

110(k)(5) is not a reasonable interpretation of the statute because by this logic, the EPA could 

never require states to update grossly out-of-date SIP provisions so long as the provisions 

originally met CAA requirements. Given that the CAA creates a process by which the EPA is 

required to establish and to update the NAAQS on a continuing basis, and states are required to 

update and revise their SIPs on a continuing basis, the Agency believes that Congress would not 

have intended that SIP provisions remain static for all time simply because they were adequate 

when first developed and approved. Such an interpretation would mean that subsequent legally 

significant events such as amendments of the CAA, court decisions interpreting the CAA and 

new or revised EPA regulations are not relevant to the continuing adequacy of existing SIP 

provisions. Similarly, such an interpretation would mean that facts arising later could never 

provide a basis for a SIP call, e.g., to address interstate transport that was not evident at the time 

of the original development and approval of the SIP provisions or that needs to be addressed 

further because of a revised NAAQS. 

The commenters also argued that if a state’s SIP provision was flawed at the time the 

EPA approved it, then the Agency’s only alternative for addressing the deficient provision is 

through the error correction authority of section 110(k)(6). The EPA disagrees. The CAA 

provides a number of tools to address flawed SIPs and the EPA does not interpret these 
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provisions to be mutually exclusive. While the EPA could potentially have relied on section 

110(k)(6) to remove the deficient provisions at issue in this action, the Agency believes that 

section 110(k)(5) authority also provides a means to address flawed SIP provisions. As explained 

in the February 2013 proposal, the EPA specifically considered the relative merits of reliance on 

section 110(k)(5) and section 110(k)(6) and determined that the former was a better approach for 

this action.315 In the present circumstances, the EPA is not addressing a single targeted flaw, i.e., 

a specific SIP revision that was flawed. Moreover, the EPA is not only dealing with a multitude 

of states in this action, but also in many cases with numerous SIP provisions developed over the 

years by a specific state. The provisions at issue often are included in several different places in a 

complex SIP and can affect multiple emission limitations in the SIP that apply to sources for 

purposes of multiple NAAQS. 

Comparing the SIP call and error correction approaches, the EPA concluded that the SIP 

call authority under section 110(k)(5) provides the better approach for this action, in that it 

allows the states to evaluate the overall structure of their existing SIPs and determine how best to 

modify the affected SIP provisions in order to address the identified deficiencies. By contrast, 

use of the error correction authority under section 110(k)(6) would result in immediate 

disapproval and removal of existing SIP provisions from the SIP, which could cause confusion in 

terms of what requirements apply to sources. Moreover, the EPA’s disapproval of a SIP 

submission through an error correction that reverses a prior SIP approval of a required SIP 

provision starts a “sanctions clock,” and sanctions would apply if the state has not submitted a 

revised SIP within 18 months. Similarly, the EPA would be required to promulgate a FIP if the 

 

315 See February 2013 proposal, 78 FR 12459 at 12483, n.72. 
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Agency has not approved a revised SIP submission from the state within 24 months. In 

comparison, the sanctions and federal plan “clocks” would not start under the SIP call approach 

unless and until the state fails to submit a SIP revision in response to this SIP call, or unless and 

until the EPA disapproves that SIP submission. As explained in the February 2013 proposal, the 

EPA determined that the SIP call process was a better procedure through which to address the 

deficient SIP provisions at issue in this action. 

7. Comments that the EPA failed to consider how excess emissions resulting from SSM 

exemptions would affect compliance with specific NAAQS, including NAAQS with different 

averaging periods or different statistical forms. 

Comment: In addition to general claims that the EPA failed to provide required technical 

analysis to support the proposed SIP call to states for automatic and discretionary SSM 

exemptions, commenters specifically argued that the EPA is required to establish that these 

exemptions have caused violations in light of the considerations such as the averaging time or 

statistical form of specific NAAQS. The implication of the commenters’ argument is that in 

order to demonstrate that a given SIP provision with an SSM exemption is substantially 

inadequate under section 110(k)(5), the EPA has to establish definitively that the emissions 

during SSM events would cause a violation of a particular NAAQS. This would potentially 

include an evaluation of the impacts of the exempted emissions on NAAQS with different 

averaging periods, e.g., impacts on an annual NAAQS, a 24-hour NAAQS, or a 1-hour NAAQS, 

and impacts on NAAQS with different statistical forms, e.g., a NAAQS that measures attainment 

by an annual arithmetical mean versus one that is measured by a 98th-percentile value. 

Moreover, commenters alluded to the difficulty of ascertaining definitively how emissions of 
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specific precursor pollutants during a given exempted SSM event would affect attainment of one 

or more NAAQS. 

To support the argument that the validity of SSM exemptions must be evaluated with 

respect to specific NAAQS, the commenters relied upon recent modeling guidance for the 1-hour 

NO2 NAAQS in which, the commenters claimed, the EPA directed states to disregard emissions 

during SSM events for purposes of demonstrating compliance with that NAAQS. The 

commenters claimed that the cited EPA guidance supports their argument that emissions from a 

source during any specific SSM event are unlikely to cause a violation of the 1-hour NO2

NAAQS. Accordingly, the commenters argued that the EPA has no authority to interpret the 

CAA to preclude exemptions for emissions during SSM events without first demonstrating that 

the exempt emissions cause NAAQS violations. 

Response: As explained in the February 2013 proposal, and in response to other 

comments in this action, the EPA does not interpret section 110(k)(5) to require a specific 

technical analysis to support a SIP call related to legal deficiencies in SIP provisions. In section 

110(k)(5), Congress left it to the Agency’s discretion to determine what type and level of 

analysis is necessary to establish that a SIP provision is substantially inadequate. As explained in 

the February 2013 proposal, the EPA does not need to define the precise contours of its authority 

under section 110(k)(5) for all potential types of SIP deficiencies in this action. For purposes of 

this action, it is sufficient that the SIP provisions at issue are inconsistent with applicable 

requirements. While an ambient air quality impact analysis may be appropriate to support a SIP 

call with respect to certain requirements of the CAA, e.g., a SIP call for failure to have SIP 

provisions to prevent significant contribution to nonattainment in another state in accordance 

with section 110(a)(2)(D)(i)(I), the EPA does not interpret the CAA to require such an analysis 
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in all instances. In particular, where the substantial inadequacy is related to a failure to meet a 

fundamental legal requirement for SIP provisions, such as the requirement in section 302(k) that 

emission limitations apply continuously, the EPA does not believe that such a technical analysis 

is required. 

For example, section 302(k) does not differentiate between the legal requirements 

applicable to SIP emission limitations for an annual NAAQS versus for a 1-hour NAAQS, nor 

between any NAAQS based upon the statistical form of the respective standards. In addition to 

being supported by the text of section 302(k), the EPA’s interpretation of the requirement for 

sources to be subject to continuous emission limitations is also the most logical given the 

consequences of the commenters’ theory. The commenters’ argument provides additional 

practical reasons to support the EPA’s interpretation of the CAA to preclude exemptions for 

emissions during SSM events from SIP emission limitations as a basic legal requirement for all 

emission limitations. 

The EPA agrees that to ascertain the specific ambient impacts of emissions during a 

given SSM event can sometimes be difficult. This difficulty can be exacerbated by factors such 

as exemptions in SIP provisions that not only excuse compliance with emission limitations but 

also affect reporting or recordkeeping related to emissions during SSM events. Determining 

specific impacts of emissions during SSM events can be further complicated by the fact that the 

limited monitoring network for the NAAQS in many states may make it more difficult to 

establish that a given SSM event at a given source caused a specific violation of the NAAQS. 

Even if a NAAQS violation is monitored, it may be the result of emissions from multiple 

sources, including multiple sources having an SSM event simultaneously. The different 

averaging periods and statistical forms of the NAAQS may make it yet more difficult to 
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determine the impacts of specific SSM events at specific sources, perhaps until years after the 

event occurred. By the commenters’ own logic, there could be situations in which it is 

functionally impossible to demonstrate definitively that emissions during a given SSM event at a 

single source caused a specific violation of a specific NAAQS. 

The commenters’ argument, taken to its logical extension, could result in situations where 

a SIP emission limitation is only required to be continuous for purposes of one NAAQS but not 

for another, based on considerations such as averaging time or statistical form of the NAAQS. 

Such situations could include illogical outcomes such as the same emission limitation applicable 

to the same source simultaneously being allowed to contain exemptions for emissions during 

SSM events for one NAAQS but not for another. For example, purely hypothetically under the 

commenters’ premise, a given source could simultaneously be required to comply with a ratebased NOx emission limitation continuously for purposes of a 1-hour NO2 NAAQS but not be 

required to do so for purposes of an annual NO2 NAAQS, or the source could be required to 

comply continuously with the same NOx limitation for purposes of the 8-hour ozone NAAQS 

and the 24-hour PM2.5 NAAQS but not be required to do so for purposes of the annual PM2.5

NAAQS. Add to this the further complication that the source may be located in an area that is 

designated nonattainment for some NAAQS and attainment for other NAAQS, and thus subject 

to emission limitations for attainment and maintenance requirements simultaneously. 

Under the commenters’ premise, the same SIP emission limitation, subject to the same 

statutory definition in section 302(k), could validly include SSM exemptions for purposes of 

some NAAQS but not others. Such a system of regulation would make it unnecessarily hard for 

regulated entities, regulators and other parties to determine whether or not a source is in 

compliance. The EPA does not believe that this is a reasonable interpretation of the requirements 
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of the CAA, nor of its authority under section 110(k)(5). This unnecessary confusion is easily 

resolved simply by interpreting the CAA to require that a source subject to a SIP emission 

limitation for NOx must meet the emission limitation continuously, in accordance with the 

express requirement of section 302(k), thus making SSM exemptions impermissible. The EPA 

does not agree that the term “emission limitation” can reasonably be interpreted to allow 

noncontinuous emission limitations for some NAAQS and not others. The D.C. Circuit has 

already made clear that the term “emission limitation” means limits that apply to sources 

continuously, without exemptions for SSM events. 

Finally, the EPA disagrees with the specific arguments raised by commenters concerning 

the modeling guidance for the 1-hour NO2 NAAQS.316 As relevant here, that guidance provides 

recommendations about specific issues that arise in modeling that is used in the PSD program for 

purposes of demonstrating that proposed construction will not cause or contribute to a violation 

of the 1-hour NO2 NAAQS. Thus, as an initial matter, the EPA notes that the context of that 

guidance relates to determining the extent of emission reductions that a source needs to achieve 

in order to obtain a permit under the PSD program, which is distinct from the question of 

whether an emission limitation in a permit must assure continuous emission reductions. 

The commenters argued that this EPA guidance “allows sources to completely exclude all 

emissions during startup and shutdown scenarios.” This characterization is inaccurate for a 

number of reasons. First, the guidance in question is only intended to address certain modeling 

issues related to predictive modeling to demonstrate that proposed construction will not cause or 

 

316 See Memorandum, “Additional Clarification Regarding Application of Appendix W 

Modeling Guidance for the 1-hour NO2 National Ambient Air Quality Standard,” from T. Fox, 

EPA/OAQPS, to Regional Air Division Directors, March 1, 2011. 
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contribute to violation of the 1-hour NO2 NAAQS, for purposes of determining whether a PSD 

permit may be issued and whether the emission limitations in the permit will require sufficient 

emission reductions to avoid a violation of this standard. 

Second, to the extent that the guidance indicates that air quality considerations might in 

certain circumstances and for certain purposes be relevant to determining what emission 

limitations should apply to a source, that does not mean a source may legally have an exemption 

from compliance with existing emissions limitations during SSM events. In the guidance cited by 

the commenter, the EPA did recommend that under certain circumstances, it may be appropriate 

to model the projected impact of the source on the NAAQS without taking into account 

“intermittent” emissions from sources such as emergency generators or emissions from particular 

kinds of “startup/shutdown” operations.317 However, the EPA did not intend this to suggest that 

emissions from sources during SSM events may validly be treated as exempt in SIP emission 

limitations. Within the same guidance document, the EPA stated unequivocally that the guidance 

“has no effect on or relevance to existing policies and guidance regarding excess emissions that 

may occur during startup and shutdown.” The EPA explained further that “all emissions from a 

new or modified source are subject to the applicable permitted emission limits and may be 

subject to enforcement concerning such excess emissions, regardless of whether a portion of 

those emissions are not included in the modeling demonstration based on the guidance provided 

here.”318 In other words, even if a state elects not to include intermittent emissions from some 

types of startup and shutdown events in certain modeling exercises, this does not mean that 

 

317 Id. at 2. 

318 Id. at 11. 
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sources can be excused from compliance with the emission limitation during startup and 

shutdown, via an exemption for such emissions. 

Third, the guidance does not say that all SSM emissions may be considered intermittent 

and excluded from the modeling demonstration. The guidance explicitly recommends that the 

modeling be based on “emission scenarios that can logically be assumed to be relatively 

continuous or which occur frequently enough to contribute significantly to the annual 

distribution of daily maximum 1-hour concentrations” and gives the example that it may be 

appropriate to include startup and shutdown emissions from a peaking unit at a power plant in 

the modeling demonstration because those units go through frequent startup/shutdown cycles.319

Thus, the guidance does not support commenters’ premise that the EPA must evaluate the air 

quality impacts from SSM events in SIP actions to determine that SSM exemptions in SIP 

provisions are substantially inadequate to meet fundamental requirements of the CAA. 

8. Comments that this SIP call action is inconsistent with 1976 EPA guidance for 

such actions. 

Comment: One commenter argued that the EPA misinterpreted the term “substantially 

inadequate” in the February 2013 proposal because the Agency is reading this term differently 

than in the past. In support of this contention, the commenter pointed to a 1976 guidance 

document from the EPA concerning the question of when a SIP may be substantially inadequate. 

The commenter argued that the EPA is wrong to interpret that term to mean anything other than 

a demonstrated failure to provide for factual attainment of the NAAQS. According to the 

commenter, the content of the 1976 guidance indicates that the EPA is obligated to conduct a 

 

319 Id. at 9. 
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specific analysis to determine the air quality impact of an alleged inadequacy in a SIP provision 

and to establish and document the specific air quality impacts of the inadequacy. 

Response: The EPA disagrees with the commenter for multiple reasons. First, the 1976 

document referred to by the commenter was the EPA’s guidance on the requirements of the CAA 

as it was embodied in 1970, not as Congress substantially amended it in 1990. The 1976 

guidance pertained not to the current SIP call provision at section 110(k)(5) but rather to the 

requirements of section 110(a)(2)(H). This is particularly significant because the 1990 CAA 

Amendments added section 110(k)(5) to the statute. Although section 110(a)(2)(H) remains in 

the statute, it is primarily a requirement applicable to state “infrastructure” SIP obligations 

through which states are required to have state law authority to meet the structural SIP elements 

required in section 110(a)(2).320 In reviewing SIPs for compliance with section 110(a)(2)(H), the 

EPA verifies that state SIPs include the legal authority to respond to any SIP call. By contrast, 

the EPA’s authority to issue a SIP call under section 110(k)(5) is worded broadly, explicitly 

including the authority to make a finding of substantial inadequacy not only for failure to attain 

or maintain the NAAQS but also for failures related to interstate transport or “otherwise to 

comply with any requirement of” the CAA. 

 

320 See “Guidance on Infrastructure State Implementation Plan (SIP) Elements under Clean Air 

Act Section 110(a)(1) and 110(a)(2)” from Stephen D. Page, Director OAQPS to Regional Air 

Directors, Regions 1–10, September 13, 2013, at page 51 (explaining that a state meets section 

110(a)(2)(H) by having authority to revise its SIP in response to a SIP call). 
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Second, even setting aside that the guidance is not relevant to the EPA’s authority under 

section 110(k)(5), the 1976 guidance on its face did not purport to define the full contours of the 

term “substantially inadequate” in section 110(a)(2)(H). The 1976 guidance stated explicitly that 

“it is difficult to develop comprehensive guidelines for all cases” and only listed “[s]ome factors 

that could be considered” in evaluating whether a state’s SIP is substantially inadequate.321

While the EPA acknowledges that these factors were primarily focused upon ambient air 

considerations as suggested by the commenter, they were not limited to that topic. Moreover, the 

EPA stated that factors “other than air quality and emission data must be considered” and 

provided several examples, including potential amendments to the CAA under consideration at 

that point in time that might change state SIP obligations and thus create the need for a SIP call. 

More significantly, nothing in the 1976 guidance indicated that the EPA should or would ignore 

legal deficiencies in existing SIP provisions or that legal deficiencies are not relevant to the 

question of whether a SIP would provide for attainment of the NAAQS. 

Third, the EPA notes that the commenter did not advocate that the Agency follow the 

1976 guidance with respect to other issues, e.g., that the EPA would initiate the obligations of 

states to revise their SIPs simply by making an announcement of substantial inadequacy “without 

proposal”; that states would be required to make the necessary SIP revision within 12 months; or 

that states should make those revisions by no later than July 1, 1977. The EPA interprets the 

commenters’ silence on these aspects of the guidance as a tacit recognition that the 1976 

guidance has been superseded. 

 

321 Id. at 10–11. 
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The EPA has fully articulated its interpretation of the term “substantial inadequacy” in 

section 110(k)(5) in the February 2013 proposal. As explained in the proposal, the EPA 

interprets its current authority to include the issuance of a SIP call for the types of legal 

deficiencies identified in this action. In order to establish that these legal deficiencies are 

substantial inadequacies, the EPA does not interpret section 110(k)(5) to require the Agency to 

document precisely how each deficiency factually undermines the objectives of the CAA, such 

as attainment and maintenance of the NAAQS in a particular location on a particular date. It is 

sufficient that these provisions are inconsistent with the legal requirements for SIP provisions set 

forth in the CAA that are intended to assure that SIPs in fact do achieve the intended objectives. 

10. Comments that because the EPA has misinterpreted the statutory terms “emission 

limitation” and “continuous,” the EPA has not established a substantial inadequacy. 

Comment: Many state and industry commenters disagreed with the EPA’s interpretation 

of the CAA to prohibit SSM exemptions in SIP provisions. These arguments took many tacks, 

based on the interpretation of various statutory provisions, the applicability of the court decision 

in Sierra Club v. Johnson, alleged EPA inconsistencies with this requirement in its own NSPS 

and NESHAP regulations and a variety of other arguments. In particular, many commenters 

argued that the EPA was misinterpreting the statutory terms “emission limitation” and 

“continuous” in section 302(k) to preclude automatic or discretionary exemptions for emissions 

during SSM events in SIP provisions. As an extension of these arguments, commenters also 

argued that the EPA lacks authority under section 110(k)(5) to issue a SIP call when it has 

incorrectly interpreted a relevant statutory term as the basis for finding a SIP provision to be 

substantially inadequate. 
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Response: The EPA disagrees that it lacks authority to issue this SIP call on the grounds 

claimed by the commenters. As explained in detail in the February 2013 proposal and in this 

final action, the EPA has long interpreted the CAA to preclude SSM exemptions in SIP 

provisions. This interpretation has been stated by the EPA since at least 1982, reiterated in 

subsequent SSM Policy guidance documents, applied in a number of notice and comment 

rulemakings and upheld by courts. 

With respect to the arguments that the EPA has incorrectly interpreted the terms 

“emission limitation” and “continuous” in this action, the EPA has responded in detail in section 

VII.A.3 of this notice and need not repeat those responses here. In short, the EPA is interpreting 

those terms consistent with the relevant statutory language and consistent with the decision of the 

court in Sierra Club v. Johnson. Because the specific SIP provisions identified in this action with 

automatic or discretionary exemptions for emissions during SSM events do not limit emissions 

from the affected sources continuously, the EPA has found these provisions substantially 

inadequate to meet CAA requirements in accordance with section 110(k)(5). 

11. Comments that section 110(k)(5) imposes a “higher burden of proof” upon the EPA than 

section 110(l) and that section 110(l) requires the EPA to conduct a specific technical analysis of 

the impacts of a SIP revision. 

Comment: Commenters argued that the EPA is misinterpreting section 110(k)(5) to 

authorize a SIP call using a lower “standard” than the section 110(l) “standard” that requires 

disapproval of a new SIP provision in the first instance. The commenters stated that section 

110(k)(5) requires a determination by the EPA that a SIP provision is “substantially inadequate” 

to meet CAA requirements in order to authorize a SIP call, whereas section 110(l) provides that 

the EPA must disapprove a SIP revision provision only if it “would interfere with” CAA 
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requirements. Thus, the commenters asserted that “the SIP call standard is higher than the SIP 

revision standard.” The commenters further argued that it would be “illogical and contrary to the 

CAA to interpret section 110 to establish a lower standard for calling a previously approved SIP 

and demanding revisions to it than for disapproving that SIP in the first place.” For purposes of 

section 110(l), the commenters claimed, the EPA “is required” to rely on specific “data and 

evidence” that a given SIP revision would interfere with CAA requirements and this requirement 

is thus imposed by section 110(k)(5) as well. In support of this reasoning, the commenters relied 

on prior court decisions pertaining to the requirements of section 110(l). 

Response: The EPA disagrees with the commenters’ interpretations of the relative 

“standards” of section 110(k)(5) and section 110(l) and with the commenters’ views on the court 

decisions pertaining to section 110(l). In addition, the EPA notes that the commenters did not 

fully address the related requirements of section 110(k)(3) concerning approval and disapproval 

of SIP provisions, of section 302(k) concerning requirements for emission limitations or of any 

other sections of the CAA that are substantively germane to specific SIP provisions and to 

enforcement of SIP provisions in general.322

The commenters argued that, by the “plain language” of the CAA and because of 

“common sense,” Congress intended the section 110(k)(5) SIP call standard to be “higher” than 

 

322 CAA section 110(k)(5) states that “[w]henever the [EPA] finds that the applicable 

implementation plan for any area is substantially inadequate to attain or maintain the relevant 

[NAAQS], to mitigate adequately [] interstate pollutant transport. . . ,or to otherwise comply with 

any requirement of [the CAA], the [EPA] shall require the State to revise the plan as necessary to 

correct such inadequacies.” Section 110(l) states that, in the event a state submits a SIP revision, 

the EPA “shall not approve a revision of a plan if the revision would interfere with any 

applicable requirement concerning attainment and reasonable further progress . . . or any other 

applicable requirement of [the CAA].” Section 110(k)(3) states that the EPA “shall approve such 

submittal . . . if it meets all the requirements of [the CAA].” 
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the section 110(l) SIP revision. The EPA disagrees that this is a question resolved by the “plain 

language.” To the contrary, the three most relevant statutory provisions, section 110(k)(3), 

section 110(l), and section 110(k)(5), are each to some degree ambiguous and are likewise 

ambiguous with respect to how they operate together to apply to newly submitted SIP provisions 

versus existing SIP provisions. Section 110(k)(3) requires the EPA to approve a newly submitted 

SIP provision “if it meets all of the applicable requirements of [the CAA].” Implicitly, the EPA 

is required to disapprove a SIP provision if it does not meet all applicable CAA requirements. 

Section 110(l) provides that the EPA may not approve any SIP revision that “would interfere 

with . . . any other applicable requirement of [the CAA].” Section 110(k)(5) provides that the 

EPA shall issue a SIP call “whenever” the Agency finds an existing SIP provision “substantially 

inadequate . . . to otherwise comply with [the CAA].” None of the core terms in each of the three 

provisions is defined in the CAA. Thus, whether the “would interfere with” standard of section 

110(l) is per se a “lower” standard than the “substantially inadequate” standard of section 

110(k)(5) as advocated by the commenters is not clear on the face of the statute, and thus the 

EPA considers these terms ambiguous. 

As explained in detail in the February 2013 proposal, the EPA interprets its authority 

under section 110(k)(5) broadly to include authority to require a state to revise an existing SIP 

provision that fails to meet fundamental legal requirements of the CAA.323 The commenters raise 

a valid point that section 110(l) and section 110(k)(5), as well as section 110(k)(3), facially 

appear to impose somewhat different standards. However, the EPA does not agree that the proper 

comparison is necessarily between section 110(k)(5) and section 110(l) but instead would 

 

323 See February 2013 proposal, 78 FR 12459 at 12483–88. 
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compare section 110(k)(5) and section 110(k)(3). Section 110(l) is primarily an “antibacksliding” provision, meant to assure that if a state seeks to revise its SIP to change existing

SIP provisions that the EPA has previously determined did meet CAA requirements, then there 

must be a showing that the revision of the existing SIP provisions (e.g., a relaxation of an 

emission limitation) would not interfere with attainment of the NAAQS, reasonable further 

progress or any other requirement of the CAA. By contrast, section 110(k)(3) is a more 

appropriate point of comparison because it directs the EPA to approve a SIP provision “that 

meets all applicable requirements” of the CAA and section 110(k)(5) authorizes the EPA to issue 

a SIP call for previously approved SIP provisions that it later determines do not “comply with 

any requirement” of the CAA. 

Notwithstanding that each of these three statutory provisions applies to different stages of 

the SIP process, all three of them explicitly make compliance with the legal requirements of the 

CAA a part of the analysis. At a minimum, the EPA believes that Congress intended these three 

sections, working together, to ensure that SIP provisions must meet all applicable legal CAA 

requirements when they are initially approved and to ensure that SIP provisions continue to meet 

CAA requirements over time, allowing for potential amendments to the CAA, changes in 

interpretation of the CAA by the EPA or courts or simply changed facts. With respect to 

compliance with the applicable legal requirements of the CAA, the EPA does not interpret 

section 110(k)(5) as setting a per se “higher” standard. Under section 110(l), the EPA is likewise 

directed not to approve a SIP revision that is not consistent with legal requirements imposed by 

the CAA, including those relevant to SIP provisions such as section 302(k). Pursuant to section 

110(l), the EPA would not be authorized to approve a SIP revision that contradicts requirements 
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of the CAA; pursuant to section 110(k)(5) the EPA is authorized to direct states to correct a SIP 

provision that it later determines does not meet the requirements of the CAA. 

The EPA also disagrees with the commenters’ characterization of the requirements of 

section 110(l) and their arguments based on court decisions concerning section 110(l). 

Commenters rely on the decision in Ky. Res Council v. EPA to support their argument that 

section 110(l) requires the EPA to disapprove a SIP revision only if it “would interfere” with a 

requirement of the CAA, not if it “could interfere” with such requirements.324 From this decision, 

the commenters argue that the EPA is required to conduct a specific technical analysis under 

section 110(l) to determine the specific impacts of the revision on attainment and maintenance of 

the NAAQS and argue that by inference this must therefore also be required by section 

110(k)(5). To the extent that court decisions concerning section 110(l) are relevant, these court 

decisions do not support the commenters’ position. 

First, the EPA notes that the commenters mischaracterize section 110(l) as requiring a 

particular form or method of analysis to support approval or disapproval of a SIP revision. 

Section 110(l) does not contain any such explicit requirement or specifications. The EPA 

interprets section 110(l) only to require an analysis that is appropriate for the particular SIP 

revision at issue, and that analysis can take different forms or different levels of complexity 

depending on the facts and circumstances relevant to the SIP revision. Like section 110(l), the 

EPA believes that section 110(k)(5) does not specify a particular form of analysis necessary to 

find a SIP provision substantially inadequate. 

 

324 See 467 F.3d 986 (6th Cir. 2006). 
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Second, the commenters mischaracterize the primary decision that they rely upon. The 

court in Ky. Res Council v. EPA expressly discussed the fact that section 110(l) does not specify 

precisely how any such analysis should be conducted and deferred to the EPA’s reasonable 

interpretation of what form of analysis is appropriate for a given SIP revision.325 Indeed, the 

decision stands for the proposition that the EPA does not necessarily have to develop an 

attainment demonstration in order to evaluate the impacts of a SIP revision, i.e. “prove” whether 

the revision will interfere with attainment, maintenance, reasonable further progress or any other 

requirements of the CAA. Thus, the commenters’ argument that section 110(k)(5) has to require 

a specific technical analysis of impacts on attainment and maintenance because section 110(l) 

does so is simply in error. 

Third, the section 110(1) cases cited by the commenters did not involve SIP revisions in 

which states sought to change existing SIP provisions so that they would fail to meet the specific 

CAA requirements at issue in this action. For example, none of the cases involved the EPA’s 

approval of a new automatic exemption for emissions during SSM events. Had the state 

submitted a SIP revision that failed to meet applicable requirements of the CAA for SIP 

provisions, such as changing existing SIP emission limitations so that they would thereafter 

include SSM exemptions, then the EPA would have had to disapprove them.326 The challenged 

rulemaking actions at issue in the cases relied upon by the commenters involved SIP revision 

changes unrelated to the specific legal requirements at issue in this action. Accordingly, the 

 

325 See 467 F.3d at 995 (rejecting claim that section 110(l) required a modeled attainment 

demonstration to prove that the SIP revision would meet applicable CAA requirements). 

326 The EPA notes that the one exception to this, of course, is the Agency’s recent approval of 

new SIP provisions in Texas that created an affirmative defense for malfunctions. As discussed 

elsewhere in this notice, however, the EPA has determined that such provisions do not meet 

CAA requirements and is thus issuing a SIP call for those provisions. 
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EPA’s evaluation of those SIP revisions focused upon other issues, such as whether the revision 

would factually result in emissions that would interfere with attainment and maintenance of the 

NAAQS, that were relevant to the particular provisions at issue in those cases. 

12. Comments that the EPA is misinterpreting US Magnesium and that the decision provides 

no precedent for this action. 

Comment: A number of industry commenters argued that the EPA’s reliance on the 

decision of the Tenth Circuit in US Magnesium, LLP v. EPA is misplaced.327 According to the 

commenters, the EPA did not correctly interpret the decision and is misapplying it in acting upon 

the Petition. The commenters asserted that the decision provides no precedent for this action 

because it was decided upon issues different from those at issue here. Commenters also argued 

that the court did not reach an important issue because the petitioner had failed to comment on it, 

i.e., the argument that the EPA had not defined the term “substantially inadequate” in the 

rulemaking.328 

Response: The EPA disagrees with the commenters on this point. The EPA of course 

acknowledges that the court in US Magnesium did not address the full range of issues related to 

the correct treatment of emissions during SSM events in SIP provisions that were raised in the 

Petition, e.g., the court did not need to address the legal basis for affirmative defense provisions 

in SIPs because of the nature of the SIP provisions at issue. However, the US Magnesium court 

evaluated many of the same key questions raised in this rulemaking and reached decisions that 

are very relevant to this action. 

 

327 See 690 F.3d 1157 (10th Cir. 2012). 

328 Id., 690 F.3d 1167, n.3. 
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First, the US Magnesium court specifically upheld the EPA’s SIP call action requiring the 

state to remove or revise a SIP provision that included an automatic exemption for emissions 

from sources during “upsets,” i.e., malfunctions. In doing so, the court was fully aware of the 

reasons why the EPA interprets the CAA to prohibit such exemptions, because they violate 

statutory requirements including section 302(k), section 110(a)(2(A) and (C), and other 

requirements related to attainment and maintenance of the NAAQS. The court explained at 

length the EPA’s reasoning about why the SIP provisions were inconsistent with CAA 

requirements for SIP provisions.329 

Second, the court specifically upheld the EPA’s SIP call action requiring the state to 

revise its SIP to remove or revise another SIP provision that could be interpreted to give state 

personnel the authority to determine unilaterally whether excess emissions from sources are a 

violation of the applicable emission limitation and thereby preclude any enforcement action by 

the EPA or citizens. 

Third, the court also upheld the EPA’s authority to issue a SIP call requiring a state “to 

clarify language in the SIP that could be read to violate the CAA, when a court has not yet 

interpreted the language in that way.” Indeed, the court opined that “in light of the potential 

conflicts” between competing interpretations of the SIP provision, “seeking revision of the SIP 

was prudent, not arbitrary or capricious.”330 

Fourth, the court explicitly upheld the EPA’s reasonable interpretation of section 

110(k)(5) to authorize a SIP call when a state’s SIP provision is substantially inadequate to meet 

applicable legal requirements, without making “specific factual findings” that the deficient 

 

329 Id., 690 F.3d at 1159–63 

330 Id., 690 F.3d at 1170. 
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provision resulted in a NAAQS violation. The EPA interpreted the CAA to allow a SIP call if the 

Agency “determined that aspects of the SIP undermine the fundamental integrity of the CAA’s 

SIP process and structure, regardless of whether or not the EPA could point to specific instances 

where the SIP allowed violations of the NAAQS.” The US Magnesium court explicitly agreed 

that section 110(k)(5) authorizes issuance of a SIP call “where the EPA determines that a SIP is 

no longer consistent with the EPA’s understanding of the CAA.”331 

Fifth, the court rejected claims that the EPA was requiring states to comply with the SSM 

Policy guidance rather than the CAA requirements, and the court noted that the Agency had 

undertaken notice-and-comment rulemaking to evaluate whether the SIP provisions at issue were 

consistent with CAA requirements.332 

Sixth, the court rejected the claim that the EPA was interpreting the requirements of the 

CAA incorrectly because the EPA is in the process of bringing its own NSPS and NESHAP 

regulations into line with CAA requirements for emission limitations, in accordance with the 

Sierra Club v. Johnson decision.333 The court noted that the EPA is now correcting SSM 

exemptions in its own regulations, and thus its prior interpretation of the CAA, rejected by the 

court in Sierra Club v. Johnson, did not make the SIP call to Utah arbitrary and capricious.334 

On these and many other issues, the EPA believes that the court’s decision in US 

Magnesium provides an important and correct precedent for the Agency’s interpretation of the 

CAA in this action. The commenters’ apparent disagreement with the court does not mean that 

the decision is not relevant to this action. The commenters specifically argued that the US 

 

331 Id., 690 F.3d at 1168. 

332 Id., 690 F.3d at 1168. 

333 Id., 690 F.3d at 1169. 

334 Id., 690 F.3d at 1170. 
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Magnesium court did not reach the issue of whether the EPA had “defined” the term “substantial 

inadequacy” in the challenged rulemaking because the petitioner had not raised this point in 

comments. The EPA does not necessarily agree that “defining” the full contours of the term is a 

necessary step for a SIP call, but regardless of that fact the Agency did explain its interpretation 

of the term “substantial inadequacy” with respect to the SIP provisions at issue in the February 

2013 proposal, the SNPR and this final action. 

13. Comments that EPA has to evaluate a SIP “as a whole” to have the authority to issue a 

SIP call. 

Comment: Many state and industry commenters argued that the EPA cannot evaluate 

individual SIP provisions in isolation and that the Agency is required to evaluate the entire SIP 

and any related permit requirements in order to determine if a specific SIP provision is 

substantially inadequate. In particular, some commenters argued that the EPA was wrong to 

focus upon the exemptions in SIP emission limitations for emissions during SSM events without 

considering whether some other requirement of the SIP or of a permit might operate to override 

or otherwise modify the exemptions. Many of the commenters asserted that other “general duty” 

clause requirements, elsewhere in other SIP provisions or in permits for individual sources, make 

the SSM exemptions in SIP emission limitations valid under the CAA.335 These other 

requirements were often general duty-type standards that require sources to minimize emissions, 

 

335 The EPA notes that other commenters on the February 2013 proposal made similar arguments 

with respect to affirmative defense provisions in their SIPs, asserting that other SIP provisions or 

terms in permits provided additional criteria that would have made the affirmative defense 

provisions at issue consistent with the EPA’s interpretation of the CAA in the 1999 SSM 

Guidance. See, e.g., Comment from Virginia Department of Environmental Quality at 1–2, in the 

rulemaking docket at EPA-HQ-OAR-2012-0322-0613. Because the EPA no longer interprets the 

CAA to allow any affirmative defense provisions, these comments are not germane. 
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to exercise good engineering judgment or not to cause a violation of the NAAQS. The 

implication of the commenters’ arguments is that such general-duty requirements legitimize an 

SSM exemption in a SIP emission limitation—even if they are not explicitly a component of the 

SIP provision, if they are not incorporated by reference in the SIP provision and if they are not 

adequate to meet the applicable substantive requirements for that type of SIP provision. 

Response: The EPA disagrees with the basic premise of the commenters that the EPA 

cannot issue a SIP call directing a state to correct a facially deficient SIP provision without first 

determining whether an unrelated and not cross-referenced provision of the SIP or of a permit 

might potentially apply in such a way as to correct the deficiency. As explained in section 

VII.A.3 of this document, the EPA believes that all SIP provisions must meet applicable 

requirements of the CAA, including the requirement that they apply continuously to affected 

sources. In reviewing the specific SIP provisions identified in the Petition, the EPA determined 

that many of the provisions include explicit automatic or discretionary exemptions for emissions 

during SSM events, whether as a component of an emission limitation or as a provision that 

operates to override the otherwise applicable emission limitation. Based on the EPA’s review of 

these provisions, neither did they apply “continuously” as required by section 302(k) nor did 

they include cross-references to any other limitations that applied during such exempt periods to 

potentially provide continuous limitations. To the extent that the SIP of a state contained any 

other requirements that applied during such periods, that fact was not plain on the face of the SIP 

provision. If the EPA was unable to ascertain what, if anything, applied during these explicitly 

exempt periods, then the Agency concludes that regulated entities, members of and the public, 

and the courts will have the same problem. The EPA has authority under section 110(k)(5) to 
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issue a SIP call requiring a state to clarify a SIP provision that is ambiguous or unclear such that 

the provision can lead to misunderstanding and thereby interfere with effective enforcement.336 

To the extent that an affected state believes that the EPA has overlooked another valid 

provision of the SIP that would cure the substantial inadequacy that the Agency has identified in 

this action, the state may seek to correct the deficient SIP provision by properly revising it to 

remove the impermissible exemption or affirmative defense and replacing it with the 

requirements of the other SIP provision or by including a clear cross-reference that clarifies the 

applicability of such provision as a component of the specific emission limitation at issue. The 

state should make this revision in such a way that the SIP emission limitation is clear on its face 

as to what the affected sources are required to do during all modes of operation. The emission 

limitation should apply continuously, and what is required by the emission limitation under any 

mode of operation should be readily ascertainable by the regulated entities, the regulators and the 

public. The EPA emphasizes, however, that each revised SIP emission limitation must meet the 

substantive requirements applicable to that type of provision (e.g., impose RACM/RACT-level 

controls on sources located in nonattainment areas) and must be legally and practically 

enforceable (e.g., have sufficient recordkeeping, reporting and monitoring requirements). The 

revised SIP emission limitation must be consistent with all applicable CAA requirements. 

14. Comments that the EPA inappropriately is “using guidance” as a basis for the SIP call 

action. 

Comment: State and industry commenters asserted that the EPA is relying on guidance as 

the basis for issuing this SIP call action and argued that the EPA cannot issue a SIP call based on 

 

336 See US Magnesium, LLC v. EPA, 690 F.3d 1157, 1169 (10th Cir. 2012). 
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guidance. The commenters argued that the EPA guidance provided in the SSM Policy is not 

binding and that states thus have the flexibility to develop SIP provisions that are not in 

conformance with EPA guidance. Some commenters claimed that if the EPA wishes to make the 

interpretations of the CAA in its SSM Policy binding upon states, then it must do so through a 

notice-and-comment rulemaking and must codify those requirements in binding regulations in 

the CFR. The commenters argued that states should not be subject to a SIP call for existing 

provisions in their SIPs on the basis that they do not conform to guidance in the SSM Policy. 

Some commenters acknowledged that the EPA is providing notice and comment on its SSM 

Policy through this action, but still they contended that the EPA’s interpretation of the CAA is 

not binding upon states unless the Agency codifies its updated SSM Policy in regulations in the 

CFR. 

Response: The EPA disagrees with arguments that the Agency has acted inappropriately 

by relying on its interpretations of the CAA set forth in the SSM Policy in issuing this SIP call. 

As explained in the February 2013 proposal, the SSM Policy is merely guidance. It is correct that 

guidance documents are nonbinding. However, the guidance provides the EPA’s 

recommendations concerning how best to interpret the statutory requirements of the CAA that 

are binding. Moreover, the EPA’s interpretation of the CAA in the SSM Policy can become 

binding once the Agency adopts and applies that interpretation through notice-and-comment 

rulemaking. The EPA is issuing this SIP call action through notice-and-comment rulemaking and 

has specifically taken comment on its interpretations of the CAA as they apply to the specific 
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SIP provisions at issue in this action. Thus, the EPA is requiring the affected states to comply 

with the requirements of the CAA, not with the SSM Policy guidance itself.337 

The EPA also disagrees with commenters that in order to rely on its interpretation of the 

CAA in the SSM Policy, the EPA must first issue regulatory provisions applicable to SIP 

provisions. There is no such general obligation for the EPA to codify its interpretations of the 

CAA in regulatory text. Unless Congress has specifically directed the EPA to promulgate 

regulations for a particular purpose, the EPA has authority and discretion to promulgate such 

regulations as it deems necessary or helpful in accordance with its authority under section 301. 

With respect to issues concerning proper treatment of excess emissions during SSM events in 

SIP provisions, the EPA has historically proceeded by issuance of guidance documents. In this 

action, the EPA is undergoing notice-and-comment rulemaking to update and revise its guidance 

and to apply that guidance to specific existing SIP provisions. Thus, the EPA is not required to 

promulgate specific implementing regulations as a precondition to making a finding of 

substantial inadequacy to address existing deficient SIP provisions. 

15. Comments that the EPA’s redesignation and approval of a maintenance plan for an area 

in a state with a SIP that has provisions at issue in the SIP call establishes that all provisions in 

the SIP meet CAA requirements. 

Comment: Commenters argued that the “EPA’s allegations that SSM provisions could 

threaten the NAAQS is contradicted by” the fact that the “EPA has consistently approved re-

 

337 The EPA’s reliance on interpretations of the CAA in the SSM Policy through notice-andcomment rulemakings has previously been upheld by several courts. See, e.g., US Magnesium. 

LLC v. EPA, 690 F.3d 1157, 1168 (10th Cir. 2012) (upholding the EPA’s SIP call to Utah for 

existing SIP provisions); Mich. Dep’t of Envtl. Quality v. Browner, 230 F.3d 181 (6th Cir. 2000) 

(upholding the EPA’s disapproval of a SIP submission). 
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designation requests and attainment and maintenance plans, notwithstanding SSM provisions.” 

According to these commenters, “[t]he fact that EPA has already approved numerous redesignation requests ... indicates that EPA has already (and in many cases, very recently) 

admitted that the [State SIPs are] fully approved, sufficient to achieve the NAAQS, and fully 

enforceable.” The commenters argued that the appropriate time for the EPA to have addressed 

any issues concerning deficient SIP provisions applicable to emissions during SSM events was 

“in the context of its review and approval of [maintenance] plans.” Because the EPA has been 

approving maintenance plans for areas in states subject to this SIP call action, the commenters 

believed, this “is evidence that the Agency has not viewed SSM-related emissions as a threat to 

attainment or maintenance of the NAAQS.” In essence, these commenters argued that the EPA’s 

redesignation of any area in any of the states at issue in this rulemaking indicates that the SIPs of 

these states fully meet all CAA requirements and that there are no deficiencies whatsoever in the 

SIPs of these states. 

Response: The EPA disagrees with the commenters’ premise that the Agency’s approval 

of redesignation requests and maintenance plans for certain nonattainment areas, notwithstanding 

the presence of impermissible provisions related to emissions during SSM events that may have 

been present in the SIP for those areas, is evidence that the EPA does not view SSM-related 

emissions as a threat to attainment or maintenance of the NAAQS. Contrary to the theory of the 

commenters, the EPA’s redesignation of an area to attainment does not mean that the SIP for the 

state in question fully meets each and every requirement of the CAA. 

The CAA sets forth the general criteria for redesignation of an area from nonattainment 

to attainment in section 107(d)(3)(E). These criteria include a determination by the EPA that the 

area has attained the relevant standard (section 107(d)(3)(E)(i)) and that the EPA has fully 
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approved the applicable implementation plan for the area for purposes of redesignation (section 

107(d)(3)(E)(ii) and (v)). The EPA must also determine that the improvement in air quality in the 

area is due to reductions that are permanent and enforceable (section 107(d)(3)(E)(iii)) and that 

the EPA has fully approved a maintenance plan for the area under section 175A (section 

107(d)(3)(E)(iv)). 

For purposes of redesignation, the EPA has long held that SIP requirements that are not 

linked with a particular nonattainment area’s designation and classification, including certain 

section 110 requirements, are not “applicable” for purposes of evaluating compliance with the 

specific redesignation criteria in CAA sections 107(d)(3)(E)(ii) and (v).338 The EPA maintains 

this interpretation because these requirements remain applicable after an area is redesignated to 

attainment. For at least the past 15 years, the EPA has applied this interpretation with respect to 

requirements to which a state will continue to be subject after the area is redesignated.339 Courts 

 

338 See, e.g., “Approval and Promulgation of Implementation Plans and Designation of Areas for 

Air Quality Planning Purposes; State of Arizona; Redesignation of the Phoenix-Mesa 

Nonattainment Area to Attainment for the 1997 8-Hour Ozone Standard; Proposed rule,” 79 FR 

16734 at 16739 n.22 (March 26, 2014). 

339 See, e.g., 73 FR 22307 at 22312–13 (April 25, 2008) (proposed redesignation of San Joaquin 

Valley; EPA concluded that section 110(a)(2)(D) transport requirements are not applicable under 

section 110(d)(3)(E)(v) because they “continue to apply to a state regardless of the designation of 

any one particular area in the state”); 62 FR 24826 at 24829–30 (May 7, 1997) (redesignation of 

Reading, Pennsylvania, Area; the EPA concluded that the additional controls required by section 

184 were not “applicable” for purposes of section 107(d)(3)(E) because “they remain in force 

regardless of the area’s redesignation status”). 
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reviewing the EPA’s interpretation of the term “applicable” in section 107(d)(3) in the context of 

requirements applicable for redesignation have agreed with the Agency.340 

The EPA therefore approves redesignation requests in many instances without passing 

judgment on every part of a state’s existing SIP, if it finds those parts of the SIP are not 

“applicable” for purposes of section 107(d)(3). For example, the EPA recently approved 

Arizona’s request to redesignate the Phoenix-Mesa 1997 8-hour ozone nonattainment area and its 

accompanying maintenance plan, while recognizing that Arizona’s SIP may contain affirmative 

defense provisions that are not consistent with CAA requirements.341 In that case, the EPA 

explicitly noted that approval of the redesignation of the Phoenix-Mesa nonattainment area did 

not relieve Arizona or Maricopa County of its obligation to remove the affirmative defense 

provisions from the SIP, if the EPA was to take later action to require correction of the Arizona 

SIP with respect to those provisions.342 

The EPA also disagrees with commenters to the extent they suggest that the Agency must 

use the redesignation process to evaluate whether any existing SIP provisions are legally 

deficient. The EPA has other statutory mechanisms through which to address existing 

deficiencies in a state’s SIP, and courts have agreed that the EPA retains the authority to issue a 

 

340 See Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004); Wall v. EPA, 265 F.3d 426, 438 (6th 

Cir. 2001). 

341 79 FR 55645 (September. 17, 2014). 

342 Id. at 55648. The EPA notes that it has included the deficient SIP provisions that include the 

affirmative defenses in this action, thereby illustrating that it can take action to address a SIP 

deficiency separately from the redesignation action, where appropriate. 
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SIP call to a state pursuant to CAA section 110(k)(5) even after redesignation of a nonattainment 

area in that state.343 The EPA recently addressed this issue in the context of redesignating the 

Ohio portion of the Huntington-Ashland (OH–WV–KY) nonattainment area to attainment for the 

PM2.5 NAAQS.344 In response to comments challenging the proposed redesignation due to the 

presence of certain SSM provisions in the Ohio SIP, the EPA concluded that the provisions at 

issue did not provide a basis for disapproving the redesignation request.345 In so concluding, the 

EPA noted that the SSM provisions and related SIP limitations at issue in that state were already 

approved into the SIP and thus “permanent and enforceable” for the purposes of meeting section 

107(d)(3)(E)(iii) and that the Agency has other statutory mechanisms for addressing any 

problems associated with the SSM provisions.346 The EPA emphasizes that the redesignation of 

areas to attainment does not relieve states of the responsibility to remove legally deficient SIP 

provisions either independently or pursuant to a SIP call. To the contrary, the EPA maintains that 

it may determine that deficient provisions such as exemptions or affirmative defense provisions 

applicable to SSM events are contrary to CAA requirements and take action to require correction 

 

343 See Southwestern Pennsylvania Growth Alliance v. EPA, 114 F.3d 984 (6th Cir. 1998) 

(Redesignation of Cleveland-Akron-Lorain area determined valid even though the Agency 

subsequently proposed a SIP call to require Ohio and other states to revise their SIPs to mitigate 

ozone transport to other states). 

344 See 77 FR 76883 (December 31, 2012). 

345 Id. at 76891–92. 

346 The EPA notes that the provisions at issue in the redesignation action are included in this SIP 

call, thus illustrating that the Agency can address these deficient provisions in a context other 

than a redesignation request. 
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of those provisions even after an area is redesignated to attainment for a specific NAAQS. This 

interpretation is consistent with prior redesignation actions. 

In some cases, the EPA has stated that the presence of illegal SSM provisions does 

constitute grounds for denying a redesignation request. For example, the EPA issued a proposed 

disapproval of Utah’s redesignation requests for Salt Lake County, Utah County and Ogden City 

PM10 nonattainment areas.347 However, the specific basis for the proposed disapproval in that 

action, which was one of many SIP deficiencies identified by EPA, was the state’s inclusion in 

the submission of new provisions not previously in the SIP that would have provided blanket 

exemptions from compliance with emission standards during SSM events. Those SSM 

exemptions were not in the previously approved SIP, and the EPA declined to approve them in 

connection with the redesignation request because such provisions are inconsistent with CAA 

requirements. In most redesignation actions, states have not sought to create new SIP provisions 

that are inconsistent with CAA requirements as part of their redesignation requests or 

maintenance plans. 

Finally, the EPA disagrees with commenters that approval of a maintenance plan for any 

area has the result of precluding the Agency from later finding that certain SIP provisions are 

substantially inadequate under the CAA on the basis that those provisions may interfere with 

attainment or maintenance of the NAAQS or fail to meet any other legal requirement of the 

CAA. The approval of a state’s redesignation request and maintenance plan for a particular 

NAAQS is not the conclusion of the state’s and the EPA’s responsibilities under the CAA but 

rather is one step in the process Congress established for identifying and addressing the nation’s 

 

347 74 FR 62717 (December 1, 2009). 
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air quality problems on a continuing basis. The redesignation process allows states with 

nonattainment areas that have attained the relevant NAAQS to provide the EPA with a 

demonstration of the control measures that will keep the area in attainment for 10 years, with the 

caveat that the suite of measures may be revisited if necessary and must be revisited with a 

second maintenance plan for the 10 years following the initial 10-year maintenance period. 

Moreover, it is clear from the structure of section 175A maintenance plans that Congress 

understood that the EPA’s approval of a maintenance plan is not a guarantee of future attainment 

air quality in a nonattainment area. Rather, Congress foresaw that violations of the NAAQS 

could occur following a redesignation of an area to attainment and therefore required section 

175A maintenance plans to include contingency measures that a state could implement quickly 

in response to a violation of a standard. The notion that the EPA’s approval of a maintenance 

plan must be the last word with regard to the contents of a state’s SIP simply does not comport 

with the framework Congress established in the CAA for redesignations. The EPA has 

continuing authority and responsibility to assure that a state’s SIP meets CAA requirements, 

even after approving a redesignation request for a particular NAAQS. 

In conclusion, the EPA is not required to reevaluate the validity of all previously 

approved SIP provisions as part of a redesignation. The existence of provisions such as 

impermissible exemptions and affirmative defenses applicable during SSM events in an 

approved SIP does not preclude the EPA’s determination that emission reductions that have 

provided for attainment and that will provide for maintenance of a NAAQS in a nonattainment 

area are “permanent and enforceable,” as those terms are meant in section 107(d)(3), or that the 

state has met all applicable requirements under section 110 and part D relevant for the purposes 

of redesignation. Finally, if the EPA separately determines that the state’s SIP is deficient after 
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the redesignation of the area to attainment, the Agency can issue a SIP call requiring a corrective 

SIP revision. Redesignation of areas to attainment in no way relieves states of their continuing 

responsibilities to remove deficient SIP provisions from their SIPs in the event of a SIP call. 

16. Comments that in issuing a SIP call the EPA is “dictating” to states how to regulate their 

sources and taking away their discretion to adopt appropriate control measures of their own 

choosing in developing a SIP. 

Comment: Several commenters claimed that the EPA’s SIP call action removes discretion 

that states would otherwise have under the CAA. Commenters claimed that the action has the 

effect of unlawfully directing states to impose a particular control measure by requiring the state 

to regulate all periods of operation for any source it chooses to regulate. Because the alternative 

emission limitations and work practice standards that the EPA asserts are necessary under the 

statutory definition of “emissions limitation” are not real options in some cases, the commenters 

claimed, the EPA’s proposal is the type of mandate that the court in the Virginia decision found 

to have violated the CAA.348 Other commenters also cited to the Virginia decision, as well as 

citing to the U.S. Supreme Court’s decision in Train v. NRDC, in which the Court held that “so 

long as the ultimate effect of a State’s choice of emissions limitations is compliance with the 

national standards, the State is at liberty to adopt whatever mix of emissions limitations it deems 

best suited to its particular situation.”349 The commenters concluded that the EPA cannot 

prescribe the specific terms of SIP provisions applicable to SSM events absent evidence that the 

provisions undermine the NAAQS or are otherwise inconsistent with the Act. 

 

348 108 F.3d at 1410. 

349 421 U.S. 60, 79 (1975). 
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Commenters claimed that states are provided substantial discretion under the Act to 

develop SIPs and that the EPA’s SIP call action is inconsistent with this long-recognized 

discretion because it limits the states to one option: “eliminate any consideration of unavoidable 

emissions during planned startups and shutdowns and adopt only an extremely limited 

affirmative defense for unavoidable emissions during a malfunction.” The commenters claimed 

that other options available to states include “justifying existing provisions, adopting alternative 

numeric emission limitations, work practice standards, additional operational limitations, or 

revising existing numeric emission limitations and/or their associated averaging times to create a 

sufficient compliance margin for unavoidable SSM emissions.” 

The commenters further asserted that the EPA’s February 2013 proposal contained 

inconsistent statements about how the Agency expects states to respond to the SIP call. For 

example, according to one commenter, the EPA states in one place that startup and shutdown 

emissions above otherwise applicable limits must be considered a violation yet elsewhere 

discusses the fact that states can adopt alternative emission limitations for startup and shutdown. 

The commenter also asserted that the EPA recommended that states could elect to adopt the an 

approach to emissions during startup and shutdown like that of the EPA’s recent MATS rule but 

that the EPA then failed to explain that the MATS rule contains “exemptions” for emissions 

during startup and shutdown that apply so long as the source meets the general work practice 

standards in the rule. This commenter claimed that the EPA’s own approach is inconsistent with 

statements in the February 2013 proposal that states should treat all startups and shutdowns as 

“normal operations.” 

Response: The EPA disagrees with the commenter’s claims that the SIP call violates the 

structure of “cooperative federalism” that Congress enacted for the SIP program in the CAA. 
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Under this structure, the EPA establishes national ambient air quality standards and reviews state 

plans to ensure that they meet the requirements of the CAA. States take primary responsibility 

for developing plans to attain and maintain the NAAQS, but the EPA is required to step in if 

states fail to adopt plans that meet the statutory requirements. As the court in Virginia

recognized, Congress gave states discretion in choosing the “mix of controls” necessary to attain 

and maintain the NAAQS. See also Train v. NRDC, 421 U.S. 60, 79, 95 (1975). The U.S. 

Supreme Court first recognized this program of cooperative federalism in Train, and the Court 

stated: 

“The Act gives the Agency no authority to question the wisdom of a State’s 

choices of emissions limitations if they are part of a plan which satisfies the 

standards of § 110(a)(2) ... [S]o long as the ultimate effect of a State’s choice of 

emissions limitations is compliance with the national standards, the State is at 

liberty to adopt whatever mix of emissions limitations it deems best suited to its 

particular situation.” 

The issue in that case concerned whether changes to requirements that would occur before the 

area was required to attain the NAAQS were variances that should be addressed pursuant to the 

provision governing SIP revisions or were “postponements” that must be addressed under section 

110(f) of the CAA of 1970, which contained prescriptive criteria. The court concluded that the 

EPA reasonably interpreted section 110(f) not to restrict a state’s choice of the mix of control 

measures needed to attain the NAAQS and that revisions to SIPs that would not impact 

attainment of the NAAQS by the attainment date were not subject to the limits of section 110(f). 

While the court recognized that states had discretion in determining the appropriate emissions 

limitations, it also recognized that the SIP must meet the standards of section 110(a)(2). In 

Virginia, the issue was whether at the request of the Ozone Transport Commission the EPA 
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could mandate that states adopt specific motor vehicle emission standards more stringent than 

those mandated by CAA sections 177 and 202 for regulating emissions from motor vehicles. 

As the EPA has consistently explained in its SSM Policy, the Agency does not believe 

that exemptions from compliance with any applicable SIP emission limitation requirements 

during periods of SSM are consistent with the obligation of states in SIPs, including the 

requirements to demonstrate that plans will attain and maintain the NAAQS, protect PSD 

increments and improve visibility. If a source is free from any obligation during periods of SSM, 

there is nothing restraining those emissions and such emissions could cause or contribute to an 

exceedance or violation of the NAAQS. Moreover, neither the state nor citizens would have 

authority to take enforcement action regarding such emissions. Also, even if historically such 

excess emissions have not caused or contributed to an exceedance or violation, this would not 

mean that they could not do so at some time in the future. Finally, given that there are many 

locations where air quality is not monitored such that a NAAQS exceedance or violation could 

be observed, the inability to demonstrate that such excess emissions have not caused or 

contributed to an exceedance or violation would not be proof that they have not. Thus, the EPA 

has long held that exemptions from emission limitations for emissions during SSM events are not 

consistent with CAA requirements, including the obligation to attain and maintain the NAAQS 

and the requirement to ensure adequate enforcement authority. 

Despite claims by the commenter to the contrary, the EPA has not mandated the specific 

means by which states should regulate emissions from sources during startup and shutdown 

events. Requiring states to ensure that periods of startup and shutdown are regulated consistent 

with CAA requirements is not tantamount to prescribing the specific means of control that the 

state must adopt. By the SIP call, the EPA has simply explained the statutory boundaries to the 
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states for SIP provisions, and the next step is for the states to revise their SIPs consistent with 

those boundaries. States remain free to choose the “mix of controls,” so long as the resulting SIP 

revisions meet CAA requirements. The EPA agrees with the commenter who notes several 

options available to the states in responding to the SIP call. The commenter stated that there are 

various options available to states, such as “adopting alternative numeric emission limitations, 

work practice standards, additional operational limitations, or revising existing numeric emission 

limitations and/or their associated averaging times to create a sufficient compliance margin for 

unavoidable SSM emissions.” However, the state must demonstrate how that mix of controls for 

all periods of operation will ensure attainment and maintenance of the NAAQS or meet other 

required goals of the CAA relevant to the SIP provision, such as visibility protection. For 

example, if a state chooses to modify averaging times in an emission limitation to account for 

higher emissions during startup and shutdown, the state would need to consider and demonstrate 

to the EPA how the variability of emissions over that averaging period might affect attainment 

and maintenance of a NAAQS with a short averaging period (e.g., how a 30-day averaging 

period for emissions can ensure attainment of an 8-hour NAAQS). One option noted by the 

commenter, “justifying existing provisions,” does not seem promising, based on the evaluation 

that the EPA has performed as a basis for this SIP call action. If by justification, the commenter 

simply means that the state may seek to justify continuing to have an exemption for emissions 

during SSM events, the EPA has already determined that this is impermissible under CAA 

requirements. 

The EPA regrets any confusion that may have resulted from its discussion in the 

preamble to the February 2013 proposal. The EPA’s statement that startup and shutdown 

emissions above otherwise applicable limitations must be considered a violation is simply 
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another way of stating that states cannot exempt sources from complying with emissions 

standards during periods of startup and shutdown. This is not inconsistent with the EPA’s 

statement that states can develop alternative requirements for periods of startup and shutdown 

where emission limitations that apply during steady-state operations could not be feasibly met. In 

such a case, startup and shutdown emissions would not be exempt from compliance but rather 

would be subject to a different, but enforceable, standard. Then, only emissions that exceed such 

alternative emission limitations would constitute violations. 

17. Comments that because areas are in attainment of the NAAQS, SIP provisions such as 

automatic exemptions for excess emissions during SSM events are rendered valid under the 

CAA. 

Comment: Commenters argued that SSM exemptions should be permissible in SIP 

provisions applicable to areas designated attainment because, they asserted, there is evidence that 

the exemptions do not result in emissions that cause violations of the NAAQS. To support this 

contention, the commenters observed that a number of states with SSM exemptions in SIP 

provisions at issue in this SIP call are currently designated attainment in all areas for one or all 

NAAQS and also that some of these states had areas that previously were designated 

nonattainment for a NAAQS but subsequently have come into attainment. Thus, the commenters 

asserted, the SIP provisions that the EPA identified as deficient due to SSM exemptions must 

instead be consistent with CAA requirements because these states are in attainment. The 

commenters claimed that because these areas have shown they are able to attain and maintain the 

NAAQS or to achieve emission reductions, despite SSM exemptions in their SIP provisions, the 

EPA’s concerns with respect to SSM exemptions are unsupported and unwarranted. Based on the 

premise that SSM exemptions are not inconsistent with CAA requirements applicable to areas 
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that are attaining the NAAQS, the commenters claimed that such provisions cannot be 

substantially inadequate to meet CAA requirements. 

Response: The EPA disagrees with the commenters’ view that, so long as the provisions 

apply in areas designated attainment, the CAA allows SIP provisions with exemptions for 

emissions during SSM events. The commenters based their argument on the incorrect premise 

that SIP provisions applicable to sources located in attainment areas do not also have to meet 

fundamental CAA requirements such as sections 110(a)(2)(A), 110(a)(2)(C) and 302(k). 

Evidently, the commenters were only thinking narrowly of the statutory requirements applicable 

to SIP provisions in SIPs for purposes of part D attainment plans, which are by design intended 

to address emissions from sources located in nonattainment areas and to achieve attainment of 

the NAAQS in such areas. The EPA does not interpret the fundamental statutory requirements 

applicable to SIP provisions (e.g., that they impose continuous emission limitations) to apply 

exclusively in nonattainment areas; these requirements are relevant to SIP provisions in general. 

The statutory requirements applicable to SIPs are not limited to areas designated 

nonattainment. To the contrary, section 107(a) imposes the responsibility on each state to attain 

and maintain the NAAQS “within the entire geographic areas comprising such State.” The 

requirement to maintain the NAAQS in section 107(a) clearly applies to areas that are designated 

attainment, including those that may previously have been designated nonattainment. Similarly, 

section 110(a)(1) explicitly requires states to have SIPs with provisions that provide for the 

implementation, maintenance and enforcement of the NAAQS. By inclusion of “maintenance,” 

section 110(a)(1) clearly encompasses areas designated attainment as well as nonattainment. The 

SIPs that states develop must also meet a number of more specific requirements set forth in 

section 110(a)(2) and other sections of the CAA relevant to particular air quality issues (e.g., the 
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requirements for attainment plans for the different NAAQS set out in more detail in part D). 

Among those basic requirements that states must meet in SIPS are section 110(a)(2)(C), 

requiring a permitting program applicable to sources in areas designated attainment, and section 

110(a)(2)(D)(i)(II), requiring SIP provisions to prevent interference with protection of air quality 

in areas designated attainment in other states. Part C, in turn, imposes additional requirements on 

states with respect to prevention of significant deterioration of air quality in areas designated 

attainment. Although the EPA agrees that the CAA distinguishes between, and imposes different 

requirements upon, areas designated attainment versus nonattainment, there is no indication that 

the statute distinguishes between the basic requirements for emission limitations in these areas, 

including that they be continuous. 

Section 110(a)(2)(A) requires states to include “emission limitations” in their SIPs “as 

may be necessary or appropriate to meet applicable requirements of” the CAA. The EPA notes 

that the commenters have raised other arguments concerning the precise meeting of “necessary 

or appropriate” (see section VII.A.3 of this notice), but in this context the Agency believes that 

because states are required to have SIPs that provide for “maintenance” of the NAAQS it is clear 

that the general requirements for emission limitations in SIPs are not limited to areas designated 

nonattainment. Section 110(a)(2)(A) contains no language distinguishing between emission 

limitations applicable in attainment areas and emission limitations applicable in nonattainment 

areas. Significantly, the definition of the term “emission limitation” in section 302(k) likewise 

makes no distinction between requirements applicable to sources in attainment areas versus 

nonattainment areas. The EPA sees no basis for interpreting the term “emission limitation” 

differently for attainment areas and nonattainment areas, with respect to whether such emission 

limitations must impose continuous controls on the affected sources. Most importantly, section 
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110(a)(2)(A) does explicitly require that any such emission limitations must “meet the applicable 

requirements” of the CAA, and the EPA interprets this to include the requirement that emission 

limitations apply continuously, i.e., contain no exemptions for emissions during SSM events. 

This requirement applies equally in all areas, including attainment and nonattainment areas. 

The EPA’s interpretation of the CAA in the SSM Policy has long extended to SIP 

provisions applicable to attainment areas as well as to nonattainment areas. Since at least 1982, 

the SSM Policy has stated that SIP provisions with SSM exemptions are inconsistent with 

requirements of the CAA to provide both for attainment and maintenance of the NAAQS, i.e., 

inconsistent with requirements applicable to both nonattainment and attainment areas.350 Since at 

least 1999, the EPA’s SSM Policy has clearly stated that SIP provisions with SSM exemptions 

are inconsistent with protection of PSD increments in attainment areas.351 The EPA provided its 

full statutory analysis with respect to SSM exemptions and CAA requirements applicable to 

areas designated attainment in the background memorandum accompanying the February 2013 

proposal.352 

Finally, the EPA disagrees with the commenters’ theory that, absent proof that the SIP 

deficiency has caused or will cause a specific violation of the NAAQS, the Agency lacks 

authority to issue a SIP call for SIP provisions that apply only in areas attaining the NAAQS. 

This argument is inconsistent with the plain language of section 110(k)(5). Section 110(k)(5) 

authorizes the EPA to issue a SIP call whenever the SIP is substantially inadequate to attain or 

maintain the NAAQS, to mitigate interstate transport or to comply with any other CAA 

 

350 See 1982 SSM Guidance, Attachment at 1. 

351 See 1999 SSM Guidance at 2. 

352 See Memorandum, “Statutory, Regulatory, and Policy Context for this Rulemaking,” 

February 4, 2013, in the rulemaking docket at EPA-HQ-OAR-2012-0322-0029. 
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requirement. The explicit reference to a SIP’s being inadequate to maintain the NAAQS clearly 

indicates that the EPA has authority to make a finding of substantial inadequacy for a SIP 

provision applicable to attainment areas, not only for a SIP provision applicable to nonattainment 

areas. In addition, section 110(k)(5) explicitly authorizes the EPA to issue a SIP call not only in 

instances related to a specific violation of the NAAQS but rather whenever the Agency 

determines that a SIP provision is inadequate to meet requirements related to attainment and 

maintenance of the NAAQS or any other applicable requirement of the Act, including when the 

provision is inadequate to meet the fundamental legal requirements applicable to SIP provisions. 

Were the EPA’s authority limited to issuing a SIP call only in the event an area was violating the 

NAAQS, section 110(k)(5) would not explicitly include requirements related to “maintenance” 

and would not explicitly include the statement “otherwise comply with any requirement of [the 

CAA].” 

18. Comments that the EPA’s initial approval of these deficient provisions, or subsequent 

indirect approval of them through action on other SIP submissions, establishes that these 

provisions meet CAA requirements. 

Comment: A number of commenters argued that because the EPA initially approved the 

SIP provisions at issue in this rulemaking, this establishes that these provisions meet CAA 

requirements. Other commenters argued that subsequent actions on other SIP submissions in 

effect override the fact that the SIP provisions at issue are legally deficient. For example, an 

industry commenter asserted that there have been “dozens of instances where EPA has reviewed 

Alabama SIP revision submittals” and the EPA has never indicated “that it believed these rules 

to be inconsistent with the CAA.” Other state commenters made similar arguments suggesting 
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that the EPA’s original approval of these provisions, and the fact that the EPA has not previously 

taken action to require states to revise them, indicates that they are not deficient. 

Response: The EPA disagrees with these commenters. The fact that the EPA once 

approved a SIP provision does not mean that the SIP provision is per se consistent with the 

CAA, or consistent with the CAA notwithstanding any later legal or factual developments. This 

is demonstrated by the very existence of the SIP call provision in section 110(k)(5), whereby the 

EPA may find that an “applicable implementation plan for any area is substantially inadequate to 

attain or maintain the relevant [NAAQS] ... or to otherwise comply with any requirement of” the 

CAA. This SIP call authority expressly authorizes the EPA to direct a state to revise its SIP to 

remedy any substantial inadequacy, including failures to comply with legal requirements of the 

CAA. By definition, when the EPA promulgates a SIP call, this means that the Agency has 

previously approved the provision into the SIP, rightly or wrongly. The SIP call provision would 

be meaningless if a SIP provision were considered perpetually consistent with CAA 

requirements after it was originally approved, and merely because of that prior approval as 

commenters suggest. In the February 2013 proposal, the EPA acknowledged its own 

responsibility in approving provisions that were inconsistent with CAA requirements. 

The EPA also disagrees with the argument that the Agency’s action on other intervening 

SIP submissions from a state over the years since the approval of the original deficient SIP 

provision in some way negates the original deficiency. The industry commenter pointed to 

“dozens of instances where EPA reviewed Alabama SIP revision submittals” as times when the 

EPA should have addressed any SSM-related deficient SIP provisions. However, the EPA’s 

approval of other SIP revisions does not necessarily entail reexamination and reapproval of every 

provision in the SIP. The EPA often only examines the specific provision the state seeks to 
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revise in the SIP submission without reexamining all other provisions in the SIP. The EPA 

sometimes broadens its review if commenters bring other concerns to the Agency’s attention 

during the rulemaking process that are relevant to the SIP submission under evaluation. 

19. Comments that exemptions for excess emissions during exempt SSM events would not 

distort emissions inventories, SIP control measure development or modeling, because the EPA’s 

regulations and guidance concerning “rule effectiveness” adequately account for these emissions, 

and therefore the proposed SIP calls are not needed or justified. 

Comment: One commenter argued that provisions allowing exemptions or affirmative 

defenses for excess emissions during startup and shutdown are consistent with a state’s authority 

under CAA section 110 and that this is evidenced by the fact that the EPA has issued guidance 

on “rule effectiveness” that plainly takes into account a “discount” factor in a state’s 

demonstration of attainment when it chooses to adopt startup/shutdown provisions. This 

commenter cited the EPA’s definition of “rule effectiveness” at 40 CFR 51.50 and EPA guidance 

on demonstrating attainment of PM2.5 and regional haze air quality goals.353 

Response: The EPA disagrees with the characterization in this comment of past EPA 

guidance and with the conclusion that the fact of the existence of EPA guidance on “rule 

effectiveness” would support the claim that the CAA provides authority for exemptions or 

affirmative defenses for excess emissions during startup and shutdown. The EPA’s definition of 

“rule effectiveness” at 40 CFR 51.50 does not refer to startup and shutdown; it refers only to 

 

353 The commenter appears to have been meaning to cite to the draft EPA guidance document 

“Draft Guidance for Demonstrating Attainment of Air Quality Goals for PM2.5 and Regional 

Haze,” January 2, 2001. This draft guidance on PM2.5 and Regional Haze was combined with 

similar guidance on ozone in the final guidance document “Guidance on the Use of Models and 

Other Analyses for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and 

Regional Haze,” April 2007, EPA-454/B-07-002. 
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“downtime, upsets, decreases in control efficiencies, and other deficiencies in emission 

estimates,” and once defined the term “rule effectiveness” is not subsequently used within 40 

CFR part 51 in any way that would indicate that it is meant to capture the effect of exemptions 

during startup and shutdown. The EPA guidance on demonstrating attainment of PM2.5 and 

regional haze goals cited by the commenter also does not address rule effectiveness or excess 

emissions during startup and shutdown. The terms “startup” and “shutdown” do not appear in the 

attainment demonstration guidance. The EPA did issue a different guidance document in 1992 on 

rule effectiveness,354 but that document focused only on the preparation of emissions inventories 

for 1990, not on demonstrating attainment of NAAQS or regional haze goals. Moreover, the 

1992 guidance document addressed ways of estimating actual 1990 emissions in light of the 

likelihood of a degree of source noncompliance with applicable emission limitations, not on the 

emissions that would be permissible in light of the absence of a continuous emission limitation 

applicable during startup and shutdown. The terms “startup” and “shutdown” do not appear in 

the 1992 guidance. In 2005, the EPA replaced the 1992 guidance document on rule effectiveness 

as part of providing guidance for the implementation of the 1997 ozone and PM2.5 NAAQS.355

Like the 1992 guidance, the 2005 guidance associated “rule effectiveness” with the issue of 

noncompliance and did not provide any specific advice on quantifying emissions that could be 

legally emitted because of SSM exemptions in SIPs. To avoid misunderstanding, the 2005 

guidance included a question and answer on startup and shutdown emissions to the effect that 

 

354 “Guidelines for Estimating and Applying Rule Effectiveness for Ozone/CO State 

Implementation Plan Base Year Inventories,” November 1992, EPA-4S2JR-92.010. 355 “Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National 

Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations,” Appendix B, August 

2005, EPA-454/R-05-001. 
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emissions during startup and shutdown should be included in “actual emissions.” This question 

and answer included the statement, “[L]ess preferably, [emissions during startup, shutdown, 

upsets and malfunctions] can be accounted for using the rule effectiveness adjustment procedures 

outlined in this guidance.” However, other than in this question and answer, the 2005 guidance 

does not mention emissions during startup and shutdown events; it focuses on issues of 

noncompliance with applicable emission limitations. The fact that the 1992 guidance document 

did not intend for “rule effectiveness” to encompass SIP-exempted emissions during startup and 

shutdown, and that the 2005 guidance also did not, is confirmed by a statement in a more recent 

draft EPA guidance document: 

“In addition to estimating the actual emissions during startup/shutdown periods, 

another approach to estimate startup/shutdown emissions is to adjust control 

parameters via the emissions calculation parameters of rule effectiveness or 

primary capture efficiency. Using these parameters for startup/shutdown 

adjustments is not their original purpose, but can be a simple way to increase the 

emissions and still have a record of the routine versus startup/shutdown portions 

of the emissions. (Emphasis added.)”356 

Furthermore, as explained in the proposals for this action and in this notice, the EPA 

believes that it is a fundamental requirement of the CAA that SIP emission limitations be 

continuous, which therefore precludes exemptions for excess emissions during startup and 

shutdown. At bottom, although it is true that these guidance documents indicated that one less 

preferable way to account for startup and shutdown emissions could be through the rule 

effectiveness analysis, this does not in any way indicate that exemptions from emissions 

limitations would be appropriate for such periods. 

 

356 “Draft Emissions Inventory Guidance for Implementation of Ozone [and Particulate Matter]* 

National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations,” April 11, 

2014, page 62. 
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Comment: A commenter argued that the EPA has not shown any substantial inadequacy 

with respect to CAA requirements but that the closest the EPA comes to identifying a substantial 

inadequacy is in the EPA’s discussion of its concern regarding the impacts of SSM exemptions 

on the development of accurate emissions inventories for air quality modeling and other SIP 

planning. This commenter and another commenter in particular noted a passage in the February 

2013 proposal that stated that emission limitations in SIPs are used to meet various requirements 

for attainment and maintenance of the NAAQS and that all of these uses typically assume 

continuous source compliance with emission limitations.357 These commenters disagreed with 

the EPA’s statement that all of these uses typically assume continuous source compliance with 

applicable emission limitations, and the commenters cited several EPA guidance documents and 

statements that, they believe, address SSM and ensure that states do not simply assume 

continuous compliance. These commenters in addition cited to footnote 4 of the EPA’s 1999 

SSM Guidance.358 The commenters argued that as long as states are complying with the EPA’s 

inventory and modeling rules and guidance, SSM exemptions and similar applicability 

provisions have no negative impact on SIP planning. 

Response: The EPA acknowledges that the cited statement in the February 2013 proposal, 

that various types of required analysis used to develop SIPs or permits “typically assume 

continuous source compliance with emission limitations,” was an oversimplification of a 

complex situation. However, the EPA disagrees with the commenters’ assertion that the EPA’s 

 

357 February 2013 proposal, 78 FR 12459 at 12485. 

358 The EPA interprets the citation “See supra pp. 21-24” as being intended to refer to those 

pages of “Guidelines for Estimating and Applying Rule Effectiveness for Ozone/CO State 

Implementation Plan Base Year Inventories,” November 1992, EPA-4S2JR-92.010, which this 

commenter did not refer to by title. 
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inventory rules and other guidance are sufficient to ensure that SSM exemptions, where they still 

exist in SIPs, have no negative impact on SIP planning. Also, if the EPA were to allow them, 

such exemptions could become more prevalent and have a larger negative effect. More 

importantly, as explained elsewhere in this notice, the EPA believes that it is a fundamental 

requirement of the CAA that SIP emission limitations be continuous, which therefore precludes 

exemptions for excess emissions during SSM events. This would be the case even if the EPA’s 

guidance could and did ensure that SSM exemptions would have no negative impact on whether 

SIPs actually provide for attainment and maintenance of the NAAQS. 

Generally, the EPA’s guidance and rules do not say that it is correct for estimates of 

source emissions used in SIP development to be based on an assumption of continuous 

compliance with the SIP emission limitations even if the SIP contains exemptions for SSM 

periods. Rather, the EPA has generally emphasized that SIPs and permits should be based on the 

best available information on actual emissions, including in most cases the effects of known or 

reasonably anticipatable noncompliance with emission limitations that do apply.359 Because the 

EPA’s longstanding SSM Policy has interpreted the Act to prohibit exemptions during SSM 

events, it has not been a focus of EPA guidance to explain to states how to take account of such 

exemptions. As the commenters have pointed out, some aspects of some EPA guidance 

documents have some relationship to the issue of accounting for SSM exemptions. Nevertheless, 

 

359 New source permitting under the prevention of significant deterioration (PSD) program is an 

exception to the principle that the effects of noncompliance should be included in estimates of 

source emissions. The air quality impact analysis for a proposed PSD permit is based on an 

assumption that the source will operate without malfunctions. However, it may be necessary in 

this type of analysis to consider excess emissions that are the result of poor maintenance, careless 

operation or other preventable conditions. See 40 CFR part 51, appendix W, section 8.1.2, 

footnote a. 
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taken together, the EPA’s guidance does not and cannot ensure that emission estimates used in 

developing SIPs and permits correctly reflect actual emissions in all cases in which SSM 

exemptions still exist in SIPs, particularly for sources that, unlike all or most of the sources 

represented by these two commenters, are not subject to continuous emissions monitoring. For a 

source not subject to continuous emissions monitoring, when excess emissions during SSM 

events are exempted by a SIP—whether automatically, on a special showing or through 

director’s discretion—it is much more likely that those emissions would not be quantified and 

reported to the air agency such that they could be accounted for in SIP and permit development. 

For example, when the SIP includes exemptions for excess emissions during SSM events, there 

may be no motive for a source to perform a special stack test during a SSM period in which there 

is no applicable emission limitation and possibly no legal basis for an air agency to require such 

a stack test. It would also be unusual to find well-documented emission factors for such transient 

operation that could be used in place of source-specific testing. 

As explained in a response provided earlier in this notice, the EPA guidance documents 

also cited by these commenters in fact do not address how the effect of exemptions in SIPs for 

excess emissions during startup and shutdown can be accounted for in an attainment or 

maintenance demonstration. The cited 1992 “rule effectiveness” guidance in regard to issues 

such as noncompliance in the form of non-operation of control equipment, malfunctions, poor 

maintenance and deterioration of control equipment was meant to address how the issues 

affected emissions in 1990, not in a future year when the NAAQS must be attained. The 2005 

guidance also did not provide any particular advice on how “rule effectiveness” concepts could 

be used to estimate emissions during exempt SSM periods. Given that the EPA’s longstanding 

SSM Policy has been that exemptions for excess emissions during SSM events are not 
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permissible, the EPA had no reason to provide guidance on how attainment demonstrations 

should account for such exemptions. 

The commenters are right to infer that the EPA does believe that where exemptions for 

excess emissions during anticipatable events still remain in current SIPs, attainment 

demonstrations ideally should account for them. Indeed, the EPA’s guidance has recommended 

that all emissions during startup and shutdown events be included in both historical and projected 

emissions inventories.360 However, as long as exemptions for excess emissions during SSM 

events have the effect of making such excess emissions not be violations and thus not reportable 

as violations, it will be difficult for air agencies to have confidence that they have sufficient 

knowledge of the magnitude, location and timing of such emissions as would be needed to 

accurately account for those emissions in attainment demonstrations, especially for NAAQS with 

averaging periods of one day or less. The EPA has promulgated emissions inventory reporting 

rules, but these rules apply requirements to air agencies rather than to the sources that would 

have actual knowledge of startup and shutdown events and emissions. To make a complying 

inventory data submission to the EPA, an air agency does not have to obtain from sources 

information on the magnitude and timing of emissions during SSM events for which an 

exemption applies, and to the EPA’s knowledge most air agencies do not obtain this information. 

 

360 For example, see “Emissions Inventory Guidance for Implementation of Ozone and 

Particulate Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze 

Regulations,” Appendix B, August 2005, EPA-454/R-05-001. A recent draft EPA guidance on 

the preparation of emissions inventories for attainment demonstrations recognizes that, in 

contrast to startup and shutdown emissions, emissions during malfunctions are not predictable 

and do not need to be included in projected inventories for the future year of attainment. See

“Draft Emissions Inventory Guidance for Implementation of Ozone [and Particulate Matter]* 

National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations,” April 11, 

2014, page 62. 
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The EPA’s emissions inventory rules require the reporting of historical annual-total emissions 

only (and in some areas “typical” seasonal and/or daily emissions for certain pollutants), not dayto-day emissions. Actual emissions during SSM events should be included in these annual 

emissions. While data formats are available from the EPA to allow a state to segregate the total 

annual emissions during SSM events from annual emissions during other type of operation, to 

segregate the emissions is not a requirement and few states do so. Moreover, the EPA’s 

emissions inventory rules require reporting on most sources only on an “every third year” basis, 

which means that unless an air agency has authority to and does require more information from 

sources than is needed to meet the air agency’s reporting obligation to the EPA, the air agency 

will not be in a position to know whether and how, between the triennial inventory reports, 

excess emissions during startup and shutdown may be changing due to variations in source 

operation and possibly affecting attainment or maintenance. Thus, the EPA’s emissions 

inventory rules provide air agencies only limited leverage in terms of ability to obtain detailed 

information from sources regarding the extent to which actual emissions during SSM events may 

be unreported in emissions inventories, due to SIP exemptions. The EPA believes that when 

exemptions for excess emissions during SSM events are removed from SIPs, thereby making 

high emissions during SSM events specifically reportable deviations from emission limitations 

for more sources than now report them as such, it will be easier for air agencies to understand the 

timing and magnitude of event-related emissions that can affect attainment and maintenance. 

However, this belief is not the basis for this SIP call action, only an expected useful outcome of 

it. 

Footnote 4 of the EPA’s 1999 SSM Guidance suggested that “[s]tates may account for 

[potential worst-case emissions that could occur during startup and shutdown] by including them 
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in their routine rule effectiveness estimates.” This statement in the 1999 document’s footnote 

may seem at odds with the statement in this response that the “rule effectiveness” concept was 

not meant to embrace excess emissions during startup and shutdown that were allowed because 

of SIP exemptions. However, the footnote is attached to text that addresses “worst-case” 

emissions that are higher than allowed by the applicable SIP, because that text speaks about the 

required demonstration to support a SIP revision containing an affirmative defense for violations 

of applicable SIP emission limitations. Thus, estimates of such worst-case emissions would 

reflect the effects of noncompliance, which is within the intended scope of the EPA’s “rule 

effectiveness” guidance. Footnote 4 was not referring to the issue of how to account for the 

effect of SSM exemptions.361 

Comment: A number of commenters stated their understanding that the EPA has 

proposed SIP calls as a way of improving air agencies’ implementation of EPA-specified 

requirements in emissions inventory or modeling, and they stated that if this is the EPA’s 

concern then the EPA should address the issue in that context. 

Response: To clarify its position, the EPA explains here that while it believes that 

approvable SIP revisions in response to the proposed SIP calls will have the benefit of providing 

information on actual emissions during SSM events that can improve emissions inventories and 

modeling, the availability of this additional information is not the basis for the SIP calls that are 

being finalized. The EPA believes that it is a fundamental requirement of the CAA that SIP 

emission limitations be continuous, which therefore precludes exemptions for excess emissions 

during startup and shutdown. 

 

361 In light of the NRDC v. EPA decision, affirmative defense provisions are not allowed in SIPs 

any longer, so this aspect of the 1999 SSM Guidance is no longer relevant. 
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Comment: An air agency commenter stated that facilities in its state are required to 

submit data on all annual emissions, including emissions from startup and shutdown operation 

(and malfunctions), as part of its annual emissions inventory, and that it takes these emissions 

into consideration as part of SIP development. 

Response: The EPA appreciates the efforts of this commenter to develop SIPs that 

account for all emissions. However, these efforts and whatever degree of success the commenter 

enjoys do not change the fundamental requirement of the CAA that SIP emission limitations be 

continuous, which therefore precludes exemptions for excess emissions during startup and 

shutdown. 

Comment: A commenter argued that even to the extent SSM emissions present some 

level of uncertainty in model-based air quality projections, that uncertainty is small compared to 

other sources of uncertainty in modeling analyses, and so SSM emissions will not have any 

significant impact on attainment demonstrations or any underlying air quality modeling analysis. 

Response: In support of this very general statement, the commenter provided only its own 

assessment of its own experience and the similar opinion of unnamed permitting agencies. In any 

case, this SIP call action is not based on any EPA determination about how modeling 

uncertainties due to SSM exemptions in SIPs compare to other modeling uncertainties. 

20. Comments that exemptions for excess emissions during SSM events are not a concern 

with respect to PSD and protection of PSD increments. 

Comment: Commenters asserted that the EPA has not adequately explained the basis for 

its concerns about the impact of emissions during SSM events on PSD increments. 
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Response: The EPA disagrees. As explained in detail in the background memorandum 

included in the docket for this rulemaking,362 CAA section 110(a)(2)(C) requires that a state’s 

SIP must include a PSD program to meet CAA requirements for attainment areas.363 In addition, 

section 161 explains that “[e]ach [SIP] shall contain emission limitations and such other 

measures as may be necessary . . . to prevent significant deterioration of air quality for such 

region . . . designated . . . as attainment or unclassifiable.” Specifically, each SIP is required to 

contain measures assuring that certain pollutants do not exceed designated maximum allowable 

increases over baseline concentrations.364 These maximum allowable increases are known as 

PSD increments. Applicable EPA regulations require states to include in their SIPs emission 

limitations and such other measures as may be necessary in attainment areas to assure protection 

of PSD increments.365 Authorizing sources in attainment areas to exceed SIP emission 

limitations during SSM events compromises the protection of these increments. 

The commenters’ concerns seem to be focused on PSD permitting for individual sources 

rather than on emission limitations in SIPs. The commenters asserted that the EPA already 

adequately accounts for all emissions during SSM events when calculating the baseline and 

 

362 See Memorandum, “Statutory, Regulatory, and Policy Context for this Rulemaking,” 

February 4, in the rulemaking docket at EPA-HQ-OAR-2012-0322-0029. 

363 “Each implementation plan . . . shall . . . include a program to provide for . . . regulation of the 

modification and construction of any stationary source within the areas covered by the plan as 

necessary to assure that [NAAQS] are achieved, including a permit program as required in . . . 

part C.” CAA section 110(a)(2)(C). 

364 CAA section 163. 

365 See 40 CFR 51.166(c). 
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increment consumption and expressed concern about the potential for “double counting” of 

emissions by counting them both toward the baseline and against increment. The EPA agrees 

that emissions should not be double-counted and has regulatory requirements in place to ensure 

that emissions are either attributed to the baseline or counted against increment but not both.366

Nevertheless, permitting agencies base their calculations of both the baseline and increment 

consumption on air quality data representing actual emissions from sources.367 As explained 

more fully in the background memorandum accompanying the February 2013 proposal, the EPA 

is concerned that as a result of SSM exemptions in SIPs, inventories of actual emissions often do 

not include an accurate accounting of excess emissions that occur during SSM events. Moreover, 

the models used to calculate increment consumption typically assume continuous source 

compliance with applicable emission limitations.368 Authorizing exceedances of emission 

limitations during SSM events would compromise the accuracy of the projections made by these 

models. Accurate calculations of the baseline and increment consumption rely on the correct 

accounting of all emissions, including those occurring during SSM events. Without accurate 

data, the EPA cannot be certain that state agencies are calculating baseline or increment 

 

366 See 40 CFR sections 51.166 and 52.21. 

367 See CAA section 169(4) (defining baseline concentration); 40 CFR 51.166(b)(13)(i) (setting 

forth what is included in baseline concentration; 40 CFR 52.21(b)(13)(i) (same). The Federal 

Register document promulgating the revised PSD regulations also explained this point. In that 

notice, the EPA explained, “[B]aseline concentrations reflect actual air quality in an area. 

Increment consumption or expansion is directly related to baseline concentration. Any emissions 

not included in the baseline are counted against the increment. The complementary relationship 

between the concepts supports using the same approach for calculating emissions contributions 

to each.” 45 FR 52676, 52718 (August 7 1980). “Actual emissions” is defined in 40 CFR 

sections 51.166(b)(21)(i) and 52.21(b)(21)(i). 

368 See 45 FR 52717 (“increment consumption and expansion should be based primarily on 

actual emissions increases and decreases, which can be presumed to be allowable emissions for 

sources subject to source-specific emissions limitations.”). 
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consumption correctly or that increments in attainment areas are not being exceeded. For the 

foregoing reasons, the EPA is concerned that SSM exemptions in SIPs compromise the ability of 

the PSD program to protect air quality increments. 

21. Comments that because ambient air quality has improved over the duration of the CAA 

through various regulatory programs such as the Acid Rain Program, this disproves that SIP 

provisions including exemptions for excess emissions during SSM events pose any concerns 

with respect to protection of public health and the environment. 

Comment: Industry commenters claimed that because ambient air quality data show that 

air quality has been consistently improving over a period of years, this proves that exemptions 

for emissions during SSM events do not impede the ability of areas to attain and maintain the 

NAAQS. The commenters provided a chart showing percentage reduction in emissions of the 

various NAAQS pollutants ranging from 52 percent reduction in NOx between 1980 and 2010 to 

83 percent reduction in direct PM10 emissions for that same time period. The commenters further 

claimed that a significant portion of the recent emissions reductions have been achieved by 

electric utilities. The commenters also provided charts and graphs showing reductions in 

pollutants under the CAA Acid Rain Program. The commenters further claimed that the states in 

which they operate—Alabama, Florida, Georgia, Mississippi and North Carolina—are meeting 

the NAAQS, with isolated exceptions. The commenters further stated that, although the EPA 

recently has promulgated several new NAAQS, the attainment plans for those standards are not 

yet due, and thus the new standards cannot justify the SIP call. The commenters concluded by 

noting that the states’ success in achieving the various NAAQS, even as the NAAQS have been 

strengthened, demonstrates that the existing SSM exemptions in SIP provisions identified by the 

EPA do not “place the NAAQS at risk.” Regarding visibility, the commenters noted that plans to 
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show progress in meeting the regional haze goal were due in 2013 and that evidence shows that 

visibility is also improving notwithstanding the existing SSM exemptions. 

Response: The EPA agrees that many areas in the U.S. have made great strides in 

improving ambient air quality under the CAA. However, excess emissions from sources during 

SSM events have the potential to undermine that progress and are also inconsistent with the 

requirements of the CAA, as discussed elsewhere in the February 2013 proposal and in this final 

action. The EPA notes that the fact that an area has attained the NAAQS does not demonstrate 

that emissions during SSM events do not have the potential to undermine attainment or 

maintenance of the NAAQS, interfere with protection of PSD increments or interfere with 

visibility. For certain pollutants, such as lead or SO2, a single source could have a single SSM 

event that could cause an exceedance of the NAAQS that would otherwise not have occurred. It 

is through its SIP that a state demonstrates that it has in place an air quality management 

program that will attain and maintain the NAAQS on an ongoing basis, and so it is critical that 

the state, through its SIP provisions, can ensure that emissions during normal source operation 

including startup and shutdown events do not exceed levels relied on for purposes of developing 

attainment and maintenance plans. Similarly, SIP provisions designed to protect visibility must 

also meet requirements of the CAA, and exemptions for emissions during SSM events would 

likewise have the potential to undermine visibility objectives of the CAA. Thus, it is not 

appropriate to exempt emissions during these SSM events from compliance with emission 

limitations in SIPs. As explained in this final action, the state has flexibility in choosing how to 

regulate source during these periods of operation, and sources do not necessarily have to be 

subject to the same numerical emissions limitations or the same other control requirements 

during startup and shutdown that apply during other modes of operation. However, SIP emission 
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limitations must be continuous, and thus sources must be subject to requirements that apply at all 

times including during startup and shutdown. 

22. Comments that the EPA’s position that SIP provisions such as automatic exemptions for 

excess emissions during SSM events hinder effective enforcement for violations is incorrect, 

because there have been a number of citizen suits brought under the CAA. 

Comment: According to industry commenters, the EPA’s argument that deficient SIP 

provisions concerning emissions during SSM events limit enforcement of violations of emissions 

limitations under sections 113 and 304 is inaccurate, because “the facts show that SSM 

provisions do not preclude or hinder enforcement of any CAA requirements.” The commenters 

provided a list of “recent” enforcement actions and asserted that “[t]he sheer number of cases 

demonstrates that the existing regulations provide ample opportunity for enforcement.” The 

commenters cited to litigation brought by citizen groups that the commenters asserted has 

resulted in settlements including “injunctive relief and supplemental environmental projects 

(“SEPs”) worth tens of millions, if not hundreds of millions, of dollars.” The commenters also 

cited to one example to suggest that “whereas EPA and/or States may use enforcement 

discretion” in certain types of cases, “citizen groups do not.” 

Response: The EPA disagrees with the commenters’ logic that the mere existence of 

enforcement actions negates the concern that deficient SIP provisions interfere with effective 

enforcement of SIP emission limitations. The EPA believes that deficient SIP provisions can 

interfere with effective enforcement by air agencies, the EPA and the public to assure that 

sources comply with CAA requirements, contrary to the fundamental enforcement structure 

provided in CAA sections 113 and 304. For example, automatic or discretionary exemption 

provisions for excess emissions during SSM events by definition completely eliminate the 
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possibility of enforcement for what may otherwise be clear violations of emissions limitations 

during those times. Affirmative defense provisions purport to alter or eliminate the statutory 

jurisdiction of courts to determine liability or to impose remedies for violations. These types of 

provisions eliminate the opportunity to obtain injunctive relief or penalties that may be needed to 

ensure appropriate efforts to design, operate and maintain sources so as to prevent and to 

minimize excess emissions, protect the NAAQS and PSD increments and meet other CAA 

requirements. Similarly, the exemption of sources from liability for excess emissions during 

SSM events eliminates incentives to minimize emissions during those times. These exemptions 

thus reduce deterrence of future violations from the same sources or other sources during these 

periods. 

In the February 2013 proposal, the EPA discussed in detail an enforcement case that 

illustrates and supports the Agency’s position.369 In that case, citizen suit plaintiffs sought to 

bring an enforcement action against a source for thousands of self-reported exceedances of 

emission limitations in the source’s operating permit. The source asserted that those exceedances 

were not “violations,” through application of a permit provision that mirrored an underlying 

Georgia SIP provision. The U.S. Court of Appeals for the Eleventh Circuit (Eleventh Circuit) 

ultimately determined that the provision created an “affirmative defense” for SSM emissions that 

shielded the source from liability for numerous violations. The court noted that even if the 

approved provision in Georgia’s SIP was inconsistent with the EPA’s guidance on the proper 

treatment of excess emissions during SSM events, the defendant could rely on the provision 

because the EPA had not taken action through rulemaking to rectify any discrepancy.370 In this 

 

369 See February 2013 proposal, 78 FR 12459 at 12504–05. 

370 See Sierra Club, et al. v. Georgia Power Co., 443 F.3d 1346 (11th Cir. 2006). 
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final action on the Petition, the EPA has determined that the specific SIP provision at issue in 

that case is deficient for several reasons. Had that deficient SIP provision not been in the SIP at 

the time of the enforcement action, then the provision would not have had any effect on the 

outcome of the case. Instead, the courts would have evaluated the alleged violations and imposed 

any appropriate remedies consistent with the applicable CAA provisions, rather than in 

accordance with the SIP provision that imposed the state’s enforcement discretion preferences on 

other parties contrary to their rights under the CAA. 

As the outcome of this case demonstrates, the mere fact that a number of enforcement 

actions have been filed does not mean that the deficient SIP provisions identified by the EPA in 

this SIP call action do not hinder effective enforcement under sections 113 and 304. To the 

contrary, that case illustrates exactly how conduct that might otherwise be a clear violation of the 

applicable SIP emission limitations by a source was rendered immune from enforcement through 

the application of a provision that operated to excuse liability for violations and potentially 

allowed unlimited excess emissions during SSM events. 

The commenters cited 15 other enforcement cases brought by government and citizen 

groups over a span of 17 years, but the commenters do not indicate whether any SIP provisions 

relevant to emissions during SSM events were involved, nor do the commenters indicate whether 

any provisions at issue in this SIP call action were involved in any of the enforcement cases it 
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cited.371 Even if an enforcement action has been initiated, the EPA’s fundamental point remains: 

SIP provisions that exempt what would otherwise be a violation of SIP emissions limitations can 

undermine effective enforcement during times when the CAA requires continuous compliance 

with such emissions limitations. By interfering with enforcement, such provisions undermine the 

integrity of the SIP process and the rights of parties to seek enforcement for violation of SIP 

emission limitations. 

A number of commenters on the February 2013 proposal indicated that, from their 

perspective, a primary benefit of automatic or discretionary exemptions in SIP provisions 

applicable to emissions during SSM events is to shield sources from liability. Similarly, 

commenters on the SNPR indicated that, from their perspective, a key benefit of affirmative 

defense provisions is to prevent what is in their opinion inappropriate enforcement action for 

violations of SIP emission limitations during SSM events. The EPA does not agree that the 

purpose of SIP provisions should be to preclude or impede effective enforcement of SIP 

emission limitations. To the contrary, the potential for enforcement for violations of CAA 

requirements is a key component of the enforcement structure of the CAA. To the extent that 

commenters are concerned about inappropriate enforcement actions for conduct that is not in 

 

371 Even if these cases did all involve SIP provisions relevant to SSM events, the sampling of 

cases cited by the commenter still do not prove the commenter’s point. The commenter indicated 

that 11 of the 15 cited cases resulted in settlement. The EPA presumes that neither party admitted 

any fault in these settlements and it remains unknown whether the court would have found the 

existence of a violation. In addition, because these cases were settled, it is unknown whether 

exemption or affirmative defense provisions would have prevented the court from finding 

liability for violation of a CAA emissions limitation that would otherwise have applied. In one 

additional case cited by the commenter, the court determined that the defendant successfully 

asserted an affirmative defense to alleged violations of a 6-minute 40-percent opacity limit. The 

outcome of this case evidently supports the EPA’s concerns about the impacts of such 

provisions. 
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violation of CAA requirements, the EPA believes that the sources already have the ability to 

defend against any such invalid claims in court. 

23. Comments that the EPA’s alleged inclusion of “exemptions” or “affirmative defenses” in 

enforcement consent decrees negates the Agency’s interpretation of the CAA to prohibit them in 

SIP provisions. 

Comment: One industry commenter claimed that the EPA has itself recently promulgated 

an exemption for emissions during SSM events. The commenter cited an April 1, 2013, 

settlement agreement in a CAA enforcement case against Dominion Energy as an example. 

According to the commenter, this settlement agreement “provides allowances for excess 

emissions during startup and shutdown” and “allows an EGU to operate without the ESP when it 

is not practicable.” The commenter characterized this as the creation of an exemption from the 

applicable emission limitations during startup and shutdown. The commenter further alleged that 

the settlement agreement “provides for an affirmative defense to stipulated penalties for excess 

emissions occurring during start up and shutdown.” The commenter intended the fact that the 

EPA agrees to this type of provision in an enforcement settlement agreement to establish that 

affirmative defense provisions must also be valid in SIP provisions so that sources can assert 

them in the event of any violation of SIP emission limitations. 

Response: The EPA disagrees with the commenter concerning the EPA’s purported 

creation of exemptions for SSM events in enforcement consent decrees or settlement agreements. 

Consent decrees or settlement agreements negotiated by the EPA to resolve enforcement actions 

do not contain automatic exemptions for excess emissions during SSM periods or any other 

provisions that are similar to the SIP provisions that the EPA has found substantially inadequate 

in this SIP call action. 
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The EPA has the authority to enter consent decrees and settlement agreements in its 

enforcement cases and uses this discretion to resolve these cases. Settlements aim to achieve the 

best possible result for a given case, taking into account its specific circumstances and risks, but 

are still compromises between the parties to the litigation. 

The EPA also disagrees with comments that attempt to equate affirmative defense 

provisions in SIPs with affirmative defense clauses that the EPA and defendants agree to 

contractually in a consent decree or settlement agreement to resolve an enforcement case. Some 

consent decrees and settlement agreements that the EPA enters into contain provisions referred 

to as “affirmative defenses” that apply only with respect to whether a source must pay stipulated 

penalties specified in the consent decree or settlement agreement. However, the EPA does not 

believe these agreements are counter to CAA requirements. The provisions in these contractual 

agreements are distinguishable from affirmative defense provisions in SIPs for excess emissions 

during SSM events. Affirmative defenses to stipulated penalties apply only in the limited context 

of violations of the contract terms of the consent decree or settlement agreement. 

Significantly, these affirmative defense provisions apply only to the stipulated penalties 

of the consent decree or settlement agreement and do not carry over for incorporation into the 

source’s permit. Most importantly, these affirmative defense provisions do not affect the penalty 

for violations of CAA requirements in general or of SIP emission limitation violations in 

particular. Further, a consent decree is itself a court order, and where these provisions have been 

used in a consent decree they are sanctioned by the court and cannot be seen as a compromise of 

the court’s own jurisdiction or authority. Indeed, the specific consent decree cited by the 

commenter contains exactly these types of “affirmative defense” provisions that are applicable 
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only to the stipulated penalties imposed contractually by the consent decree and that do not 

operate to create any other form of affirmative defense applicable more broadly. 

The EPA’s use of these provisions in enforcement consent decrees or settlement 

agreements is not inconsistent with the EPA’s interpretation of the CAA to preclude such 

provisions in SIPs. The EPA interprets the CAA to preclude such affirmative defenses in SIP 

provisions because they purport to alter or eliminate the jurisdiction of courts to find liability or 

to impose remedies for CAA violations in the event of judicial enforcement. No such concern is 

presented by the types of provisions in consent decrees or settlement agreements raised by the 

commenters, because the terms of such agreements must be approved and sanctioned by a court. 

24. Comments that the EPA should provide more than 18 months for the SIP call because 

state law administrative process can take longer than that. 

Comment: Several state and industry commenters claimed that states will need longer 

than 18 months to submit SIPs in response to a SIP call. One state commenter argued generally 

that more time is needed for the state to “change rules and submit a proposed SIP revision” but 

did not provide any detail on how much more time is needed. The commenter concluded that a 

“total of five years” is needed for both the state to complete its actions and for facilities “to 

change operating procedures or add hardware.” Another state commenter claimed states would 

need at least 3 years to submit revised plans and cited to 40 CFR 51.166(a)(6) as providing a 3-

year window for submission of SIP revisions. 

An industry commenter asserted that it has taken EPA numerous years to address the 

startup and shutdown provisions in its own MACT standards and that states will need a similar 

amount of time to “unspin” the SSM provisions from SIP emission limitations and replace them 

with new requirements. The commenter pointed to the difficulty of modifying multiple permits 
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and source-specific or source-category specific regulations. The commenter urged the EPA to 

provide much more time that the 18 months allowed by statute for a SIP call through “a 

transition period of a reasonable length far exceeding 48 months.” 

Another industry commenter stated that more time is necessary but recognized that the 

maximum statutory period is 18 months. The commenter supported the EPA’s providing states 

with the full 18 months to submit SIP revisions, because that time is needed in order for the 

states to undertake the necessary technical analyses to support the SIP revisions and in order to 

allow for the state rulemaking processes. 

Response: The EPA recognizes that rule development and the associated administrative 

processes can be complex and time-consuming for states and for the Agency. Thus, the EPA is 

providing the maximum period allowed under CAA section 110(k)(5)—18 months—for states to 

submit SIP revisions in response to the SIP call. The EPA does not have authority under the 

statute to provide states with a longer period of time to submit these SIP submissions. To assist 

states in responding to this SIP call, the EPA is providing updated and comprehensive guidance 

concerning CAA requirements applicable to SIP provisions with respect to emissions during 

SSM events. Ideally, this guidance will allow states and the EPA to address the existing 

deficiencies as efficiently as possible, given the statutory schedules applicable to both states and 

the Agency. 

The commenter who cited to 40 CFR 51.166(a)(6) is incorrect that it provides authority 

for the EPA to grant states 3 years to correct SIPs in response to a SIP call. The regulatory 

provision cited by the commenter is part of the EPA’s regulations for the PSD program and 

simply provides that if the EPA amends that section of the PSD regulations, then a state will 

have 3 years to make a SIP submission to revise its SIP to meet the new PSD requirements in 
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response to such amendments. This final action does not amend the PSD regulations and 40 CFR 

51.166(a)(6) is not implicated. Under CAA section 110(k)(5), the EPA is only authorized to 

provide a maximum period of 18 months for states to submit SIP revisions to rectify the SIP 

deficiencies. 

25. Comments that EPA should issue an interim enforcement policy, with respect to 

enforcement between the time that states revise SIP requirements and source permits are revised 

to reflect those changes. 

Comment: One commenter argued that if the EPA finalizes the proposed SIP call for 

provisions applicable to emissions during SSM events, it will take state regulators a significant 

period of time to “disaggregate” the effect of those deficient provisions on various other SIP 

provisions and the requirements of source operating permits. Because these corrections to SIP 

provisions and permit requirements will take time to occur, the commenter asserted that “a 

transition period of reasonable length far exceeding 48 months will be needed to shield industry 

from enforcement.” The commenter thus requested that the EPA impose such a transition period. 

In addition, the commenter suggested that the EPA should create “an interim enforcement 

policy” to shield sources and allow reliance on affirmative defense provisions “even after SIPs 

are corrected until permits reflect those changes.” The commenter posed this request based upon 

concern that there will be industry confusion concerning what requirements apply to individual 

sources until permits are revised to reflect the correction of the deficient SIP provisions. 

Response: The EPA agrees with the commenter that it will take time for states to make 

the necessary SIP revisions in response to this SIP call, for the EPA to evaluate and act upon 

those SIP submissions and subsequently for states or the Agency to revise operating permits in 

the ordinary course to reflect the corrected state SIPs. As explained in the February 2013 
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proposal, the EPA consciously elected to proceed via its SIP call authority under section 

110(k)(5) and to provide the statutory maximum of 18 months for the submission of corrective 

SIP revisions. The EPA chose this path specifically in order to provide states with time to revise 

their deficient SIP provisions correctly and in the manner that they think most appropriate, 

consistent with CAA requirements. The EPA also explicitly acknowledged that during the 

pendency of the SIP revision process, and during the time that it will take for permit terms to be 

revised in the ordinary course, sources will remain legally authorized to emit in accordance with 

current permit terms.372 

The EPA is in this final action reiterating that the issuance of the SIP call action does not 

automatically alter any provisions in existing operating permits. By design, sources for which 

emission limitations are incorporated in permits will thus have a de facto transition period during 

which they can take steps to assure that they will ultimately meet the revised SIP provisions 

(e.g., by changing their equipment or mode of operation to meet an appropriate emission 

limitation that applies during startup and shutdown instead of relying on exemptions). Sources 

subject to permit requirements will thus have yet more time (beyond the 18 months allowed for 

the SIP revision in response to this SIP call action) over the permit review cycle to take steps to 

meet revised permit terms reflecting the revised SIP provisions. However, the EPA does not 

agree with the commenter that there is a need for a “transition period” to “shield” sources from 

enforcement. The EPA’s objective in this action is to eliminate impermissible SIP provisions that 

exempt emissions during SSM events or otherwise interfere with effective enforcement for 

violations that occur during such events. Further delaying the time by which sources will be 

 

372 See February 2013 proposal, 78 FR 12459 at 12482. 
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expected to comply with SIP provisions that are consistent with CAA requirements is 

inappropriate. Moreover, the primary purpose of SIP provisions is not to shield sources from 

liability for violations of CAA requirements but rather to assure that sources are required to meet 

CAA requirements. 

The EPA shares the commenter’s concern that there is the potential for confusion on the 

part of sources or other parties in the interim period between the correction of deficient SIP 

provisions and the revision of source operating permits in the ordinary course. However, the 

EPA presumes that most sources required to have a permit, especially a title V operating permit, 

are sufficiently sophisticated and aware of their legal rights and responsibilities that the 

possibility for confusion on the part of sources should be very limited. Likewise, by making clear 

in this final action that sources will continue to be authorized to operate in accordance with 

existing permit terms until such time as the permits are revised after the necessary SIP revision, 

the EPA anticipates that other parties should be on notice of this fact as well. Regardless of the 

potential for confusion by any party, the EPA believes that the legal principle of the “permit 

shield” is well known by regulated entities, regulators, courts and other interested parties. 

Accordingly, the EPA is not issuing any “enforcement policy” in connection with this SIP call 

action. 

26. Comments that a SIP call directing states to eliminate exemptions for excess emissions 

during SSM events is a “paper exercise” or “exalts form over substance.” 

Comment: A number of commenters argued that by requiring states to correct deficient 

SIP provisions, such as by requiring removal of exemptions for emissions during SSM events, 

this SIP call action will not result in any environmental benefits. For example, state commenters 

claimed that they will not be able simply to revise regulations to eliminate startup and shutdown 
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exemptions. Instead, the commenters claimed, the states will need to revise the emissions 

limitations completely in order to take into account the EPA’s interpretation of the CAA that 

such exemptions are impermissible. The commenters asserted that rewriting the state regulations 

will produce no reduction in emissions or improvement in air quality and will merely impose 

burdens upon states to change existing regulations. The implication of the commenters’ 

argument is that states will merely revise SIP emission limitations to allow the same amount of 

emissions during SSM events by some other means, rather than by establishing emission 

limitations that would encourage sources to be designed, operated and maintained in a fashion 

that would better control those emissions. 

Response: The EPA does not agree with the commenters’ assertion that revisions to the 

affected SIP provisions in response to this SIP call action will produce no emissions reductions 

or improvements in air quality. The EPA recognizes that some states may elect to develop 

revised emission limitations that provide for alternative numerical limitations, control 

technologies or work practices applicable during startup and shutdown that differ from 

requirements applicable during other modes of source operation. Other states may elect to 

develop completely revised emission limitations and elevate the level of the numerical emission 

limitation that applies at all times to account for greater emissions during startup and shutdown. 

However, any such revised emission limitations must comply with applicable substantive CAA 

requirements relevant to the type of SIP provision at issue, e.g. be RACM and RACT for sources 

located in nonattainment areas, and must meet other requirements for SIP revisions such as in 

sections 110(k)(3), 110(l) and 193. 

The EPA believes that revision of the existing deficient SIP provisions has the potential 

to decrease emissions significantly in comparison to existing provisions, such as those that 
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authorize unlimited emissions during startup and shutdown. Elimination of automatic and 

director’s discretion exemptions for emissions during SSM events should encourage sources to 

reduce emissions during startup and shutdown and to take steps to avoid malfunctions. 

Elimination of inappropriate enforcement discretion provisions and affirmative defense 

provisions should provide increased incentive for sources to be properly designed, operated and 

maintained in order to reduce emissions at all times. The EPA also anticipates that revision of 

older SIP emission limitations in light of more recent technological advances in control 

technology, and in light of more recent NAAQS, has the potential to result in significant 

emission control and air quality improvements. In any event, by bringing these provisions into 

compliance with CAA requirements, the EPA believes that the resulting SIP provisions will 

support the fundamental integrity of the SIP process and structure, both substantively and with 

respect to enforceability. 

27. Comments that the EPA should make its interpretation of the CAA with respect to SSM 

exemptions applicable only “prospectively” and not require states to correct existing deficient 

provisions. 

Comment: Commenters argued that the EPA should not issue a SIP call to states for 

existing SIP provisions and should only require states to comply with its interpretations of the 

CAA “prospectively.” One commenter argued that the SIP provisions at issue in this SIP call 

action were approved by the EPA in the past and have largely been “upheld through several EPA 

refinements and guidance on SSM since then.” The commenter estimated that the proposed SIP 

call would require states to reestablish emission limits for thousands of existing sources or could 

require existing sources to comply with emission limitations that did not originally take into 

account emissions during SSM events. The commenter characterized the EPA’s action on the 
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Petition as a change of policy with which the EPA should only require states to meet 

prospectively, putting states “on notice” that the EPA will evaluate future SIP submissions under 

a different test applicable only to new sources going forward. 

Other commenters argued that the EPA cannot require states to revise their SIP 

provisions if this would have the effect of making existing sources have to comply with the 

revised SIP. According to the commenters, existing sources should be “grandfathered” and 

should not have to change their control strategies or modes of operation to meet the revised SIP 

requirements. The commenters asserted that issuance of a SIP call without grandfathering 

existing sources would “retroactively” require sources to comply with the new SIP provisions 

and “suddenly” render sources noncompliant, even though they were in compliance with the SIP 

when they were originally designed, financed and built. The commenter claimed that the SIP call 

would “change the legal structure for commercial transactions that have already taken place.” 

The thrust of the commenters’ argument is that sources, once built, should never be subjected to 

any additional pollution control requirements once they are in existence. 

Response: The EPA disagrees with the commenters’ suggestions for multiple reasons. At 

the outset, the EPA notes that the only significant actual “change” in the Agency’s SSM Policy 

in this action is the determination that affirmative defense provisions are not permissible in SIP 

provisions. Since the 1999 SSM Guidance, the EPA had interpreted the CAA to allow such 

affirmative defense provisions, so long as they were limited only to civil penalties and very 

narrowly drawn consistent with criteria recommended by the Agency. As fully explained in 

section IV of this notice, however, the EPA has determined in light of the court’s decision in 

NRDC v. EPA that the CAA does not permit SIP provisions that operate to alter or eliminate the 

jurisdiction of the courts to determine liability and impose remedies in judicial enforcement 
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actions.373 In other respects, this action primarily consists of the EPA’s taking action to assure 

that SIP provisions are consistent with the CAA as the Agency has interpreted it in the SSM 

Policy for many years. 

In addition, it is not appropriate for the EPA to allow states to retain deficient SIP 

provisions that would continue to excuse existing sources from complying with the revised SIP 

provisions in perpetuity or that would only require that future sources comply with such revised 

SIP provisions. The commenters advocate for “grandfathering” that would authorize current 

sources to continue to operate under existing deficient SIP provisions (e.g., with exemptions for 

SSM emissions or with affirmative defense provisions) while requiring only new sources to 

comply with revised SIP provisions that meet CAA requirements. The EPA understands the 

practical reasons why the commenters make this suggestion, but such an approach would be 

grossly unfair both to new sources and to the communities affected by emissions from the old 

sources, as well as flatly inconsistent with the requirements of the CAA for SIP provisions. 

Existing sources will not be required to comply with the revised SIP emission limitations until 

the SIPs are updated, and if they are subject to permit requirements the sources may continue to 

operate consistent with those permits until the operating permits are revised to reflect the revised 

SIP requirements, but after that time current sources will be required to comply. Thus, sources 

will not immediately be in noncompliance with any requirements. The EPA has authority to 

issue a SIP call at any time that it determines a SIP provision is substantially inadequate, even if 

it mistakenly thought that the SIP provision was adequate at some time in the past. Sources will 

 

373 The EPA notes, however, that many of the affirmative defense type provisions at issue in this 

action were also not consistent with the Agency’s interpretation of the CAA in the 1999 SSM 

Guidance. Thus, even in the absence of the NRDC v. EPA decision, these provisions were not 

consistent with the EPA’s prior interpretation of the CAA for such provisions. 
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be on notice of the SIP call and the state’s administrative process to respond to it long before 

they will be required to comply with a revised SIP provision, and those sources will have ample 

opportunity to participate in the rulemakings establishing new requirements at both the state and 

federal level. 

Finally, the EPA notes, the need for states to establish new emission limitations and 

change permit terms for many sources should not be viewed as an unusual occurrence. The need 

to reexamine existing SIP provisions and permit terms applicable to sources in response to this 

SIP call action is comparable to the process that states would undertake to update their SIPs as 

necessary to meet new and evolving CAA requirements, including future revised NAAQS. For 

example, under section 110(a)(1) and section 110(a)(2) states are already required to reexamine 

and potentially to revise their SIP provisions whenever the EPA promulgates a new or revised 

NAAQS. States already need to reexamine emission limitations required by section 110(a)(2)(A) 

and other relevant sections of the CAA in their SIPs on a regular basis as the NAAQS are revised 

(e.g., the potential need to revisit what is RACT for a specific source category with respect to a 

new NAAQS), as new legal requirements are created (e.g. the potential need to address interstate 

transport including compliance with any applicable FIP addressing a SIP deficiency with respect 

to this issue), or as new emissions control technologies are developed (e.g., what is RACT for a 

pollutant may evolve with technological developments). Thus, as a general matter, states already 

engage in periodic review of their SIP provisions on a regular basis, and the potential need to 

update the emissions limitations applicable to sources and thereafter the need to update the 

permits applicable to those sources is part of that process. This SIP call action simply directs the 

affected states to address specific deficiencies in their SIP provisions as part of this normal 

evolutionary process. 
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28. Comments that directing states to correct their existing SIP provisions will require many 

sources to change terms of their operating permits. 

Comment: A number of commenters opposed the February 2013 proposal because of the 

administrative burden the rule would impose on air agencies and sources. Commenters asserted 

that requiring states to remove affirmative defense provisions for startup and shutdown from 

SIPs and to develop alternative emission limitations for such periods of operation instead is 

unreasonable. Other commenters argued that requiring removal of the deficient SIP provisions 

would impose enormous and time-consuming burdens on permitting authorities and the regulated 

community associated with the development of new or revised emissions limitations for startup 

and shutdown, the revision of SIPs and the revision of permits to incorporate such revised 

emision limitations. Another commenter asserted that sources only accepted numerical limits in 

permits with the understanding that they also had the benefit of affirmative defenses in the event 

of exceedances of those numerical emission limits during periods of SSM. The commenter thus 

argued that sources would seek to revise the permit limits in order to account for the absence of 

such affirmative defenses. 

Response: The EPA acknowledges the concerns raised by commenters concerning the 

need for air agencies to revise the deficient SIP provisions at issue in this action, as well as the 

need for the EPA to review the resulting SIP revisions. The EPA does not agree, however, with 

the commenters’ argument that the need for these administrative actions is a justification for 

leaving the deficient provisions unaddressed. 

The EPA also acknowledges that the SIP revisions initiated by this SIP call action will 

result in the removal of deficient provisions such as automatic and discretionary SSM 

exemptions, overly broad enforcement discretion provisions and affirmative defense provisions. 
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These SIP revisions will ultimately need to be reflected in revised operating permit terms for 

sources. This SIP call action will not, however, have an automatic impact on any permit terms 

and conditions, and the resource burden to revise permits will be spread over many years. After a 

state makes the necessary revisions to its SIP provisions, any needed revisions to operating 

permits to reflect the revised SIP provisions will occur in the ordinary course as the state issues 

new permits or reviews and revises existing permits. For example, in the case of title V operating 

permits, permits with more than 3 years remaining will be reopened to add new applicable 

requirements within 18 months of the promulgation of the requirements. If a permit has less than 

3 years remaining, the new applicable requirement will be added at renewal.374 

IX. What is the EPA’s final action for each of the specific SIP provisions identified in 

the Petition or by the EPA? 

A. Overview of the EPA’s Evaluation of Specific SIP Provisions 

In reviewing the Petitioner’s concerns with respect to the specific SIP provisions 

identified in the Petition, the EPA notes that most of the provisions relate to a small number of 

common issues. Many of these provisions are as old as the original SIPs that the EPA approved 

in the early 1970s, when the states and the EPA had limited experience in evaluating the 

provisions’ adequacy, enforceability and consistency with CAA requirements. 

In some instances the EPA does not agree with the Petitioner’s reading of the provision in 

question, or with the Petitioner’s conclusion that the provision is inconsistent with the 

requirements of the CAA. However, given the common issues that arise for multiple states in the 

Petition as well as in the EPA’s independent evaluation, there are some overarching conceptual 

 

374 See 40 CFR 70.7(f)(1)(i). 
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points that merit discussion in general terms. Thus, this section IX.A of the notice provides a 

general discussion of each of the overarching points, including a summary of what the EPA 

proposed to determine with respect to the relevant SIP provisions collectively. The EPA received 

comments on the proposed determinations from affected states, the Petitioner and other 

commenters. A detailed discussion of the comments received with the EPA’s responses is 

provided in the Response to Comment document available in the docket for this rulemaking. 

Sections IX.B through IX.K of this document name the specific SIP provisions identified 

in the Petition or by the EPA, including a summary of what the EPA proposed and followed by 

the EPA’s stated final action with respect to each SIP provision. 

1. Automatic Exemption Provisions 

A significant number of provisions identified by the Petitioner pertain to existing SIP 

provisions that create automatic exemptions for excess emissions during periods of SSM. 

Occasionally, these provisions also pertain to exemptions for excess emissions that occur during 

maintenance, load change or other types of normal source operation. These provisions typically 

provide that a source subject to a specific SIP emission limitation is exempted from compliance 

during SSM, so that the excess emissions are defined as not violations. Often, these provisions 

are artifacts of the early phases of the SIP program, approved before state and EPA regulators 

recognized the implications of such exemptions. Whatever the genesis of these existing SIP 

provisions, however, these automatic exemptions from emission limitations are not consistent 

with the CAA, as the EPA has stated in its SSM Policy since at least 1982. 

After evaluating the Petition, the EPA proposed to determine that a number of states have 

existing SIP provisions that create impermissible automatic exemptions for excess emissions 

during malfunctions or during startup, shutdown or other types of normal source operation. In 
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those instances where the EPA agreed that a SIP provision identified by the Petitioner contained 

such an exemption contrary to the requirements of the CAA, the EPA proposed to grant the 

Petition and accordingly to issue a SIP call to the appropriate state. 

2. Director’s Discretion Exemption Provisions 

Another category of problematic SIP provision identified by the Petitioner is exemptions 

for excess emissions that, while not automatic, are exemptions for such emissions granted at the 

discretion of state regulatory personnel. In some cases, the SIP provision in question may 

provide some minimal degree of process and some parameters for the granting of such 

discretionary exemptions, but the typical provision at issue allows state personnel to decide 

unilaterally and without meaningful limitations that what would otherwise be a violation of the 

applicable emission limitation is instead exempt. Because the state personnel have the authority 

to decide that the excess emissions at issue are not a violation of the applicable emission 

limitation, such a decision would transform the violation into a nonviolation, thereby barring 

enforcement by the EPA or others. 

The EPA refers to this type of provision as a “director’s discretion” provision, and the 

EPA interprets the CAA generally to forbid such provisions in SIPs because they have the 

potential to undermine fundamental statutory objectives such as the attainment and maintenance 

of the NAAQS and to undermine effective enforcement of the SIP. As described in sections 

VII.C and VIII.A.3 of this document, unbounded director’s discretion provisions purport to allow 

unilateral revisions of approved SIP provisions without meeting the applicable statutory 

substantive and procedural requirements for SIP revisions. The specific SIP provisions at issue in 

the Petition are especially inappropriate because they purport to allow discretionary creation of 

case-by-case exemptions from the applicable emission limitations, when the CAA does not 
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permit any such exemptions in the first instance. The practical impact of such provisions is that 

in effect they transform an enforcement discretion decision by the state (e.g., that the excess 

emission from a given SSM event should be excused for some reason) into an exemption from 

compliance that also prevents enforcement by the EPA or through a citizen suit. The EPA’s 

longstanding SSM Policy has interpreted the CAA to preclude SIP provisions in which a state’s 

exercise of its own enforcement discretion bars enforcement by the EPA or through a citizen suit. 

Where the EPA agreed that a SIP provision identified by the Petitioner contained such a 

discretionary exemption contrary to the requirements of the CAA, the EPA proposed to grant the 

Petition and to call for the state to rectify the problem. 

3. State-only Enforcement Discretion Provisions 

The Petitioner identified existing SIP provisions in many states that ostensibly pertain to 

parameters for the exercise of enforcement discretion by state personnel for violations due to 

excess emissions during SSM events. The EPA’s SSM Policy has consistently encouraged states 

to utilize traditional enforcement discretion within appropriate bounds for such violations and, in 

the 1982 SSM Guidance, explicitly recommended criteria that states might consider in the event 

that they elected to formalize their enforcement discretion with provisions in the SIP. The intent 

has been that such enforcement discretion provisions in a SIP would be “state-only,” meaning 

that the provisions apply only to the state’s own enforcement personnel and not to the EPA or to 

others. 

The EPA determined that a number of states have SIP provisions that, when evaluated 

carefully, could reasonably be construed to allow the state to make enforcement discretion 

decisions that would purport to foreclose enforcement by the EPA under CAA section 113 or by 

citizens under section 304. In those instances where the EPA agreed that a specific provision 
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could have the effect of impeding adequate enforcement of the requirements of the SIP by parties 

other than the state, the EPA proposed to grant the Petition and to take action to rectify the 

problem. By contrast, where the EPA’s evaluation indicated that the existing provision on its 

face or as reasonably construed could not be read to preclude enforcement by parties other than 

the state, the EPA proposed to deny the Petition, and the EPA invited comment on this issue in 

particular to assure that the state and the EPA have a common understanding that the provision 

does not have any impact on potential enforcement by the EPA or through a citizen suit. This 

process was intended to ensure that there is no misunderstanding in the future that the correct 

reading of the SIP provision would not bar enforcement by the EPA or through a citizen suit 

when the state elected to exercise its own enforcement discretion. 

In the February 2013 proposal, the EPA noted that another method by which to eliminate 

any potential ambiguity about the meaning of these enforcement discretion provisions would be 

for the state to revise its SIP to remove the provisions. Because these provisions are only 

applicable to the state, the EPA’s view was, and still is, that the provisions need not be included 

within the SIP. Thus, the EPA supports states that elect to revise their SIPs to remove these 

provisions to avoid any unnecessary confusion. 

4. Affirmative Defense Provisions 

The Petitioner asked the EPA to rescind its SSM Policy element that interpreted the CAA 

to allow SIPs to include affirmative defenses for violations due to excess emissions during any 

type of SSM events. Related to this request, the Petitioner asked the EPA to find that states with 

SIPs containing an affirmative defense to monetary penalties for excess emissions during SSM 

events are substantially inadequate because they do not comply with the CAA. If the EPA were 

to deny the Petitioner’s request that the EPA revise its interpretation of the CAA, the Petitioner 
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asked that the EPA in the alternative require states with SIPs that contain such affirmative 

defense provisions to revise them so that they are consistent with the EPA’s 1999 SSM Guidance 

for excess emissions during SSM events and to issue a SIP call to states with provisions 

inconsistent with the EPA’s interpretation of the CAA. 

The Petitioner drew no distinction between affirmative defense provisions for 

malfunctions versus affirmative defense provisions for startup and shutdown or other normal 

modes of operation. As explained in section IV.B of the February 2013 proposal, the EPA did 

make such distinction in its proposed response to the Petition, at that time proposing to revise its 

SSM Policy to reflect an interpretation of the CAA that affirmative defense provisions applicable 

during startup and shutdown were not appropriate but reasoning that affirmative defense 

provisions remained appropriate for violations when due to malfunction events. Thus, in the 

February 2013 proposal, the EPA proposed to issue a SIP call to a state to rectify a problem with 

an affirmative defense provision only if the provision included an affirmative defense that was 

applicable to excess emissions during startup and shutdown or included an affirmative defense 

that was applicable to excess emissions during malfunctions but was inconsistent with the 

criteria recommended in the EPA’s SSM Policy. 

Subsequent to that February 2013 proposal, a federal court ruled that the CAA precludes 

authority of the EPA to create affirmative defense provisions applicable to private civil suits. The 

NRDC v. EPA decision pertained to a challenge to the EPA’s NESHAP regulations issued 

pursuant to CAA section 112 to regulate hazardous air pollutants from sources that manufacture 

Portland cement. 375 As explained in detail in section V of the SNPR, the court’s decision in 

 

375 NRDC v. EPA, 749 F.3d 1055 (D.C. Cir. 2014). 
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NRDC v. EPA compelled the Agency to revise its interpretation of the CAA concerning the legal 

basis for affirmative defense provisions. As a result, the EPA proposed in the SNPR to further 

revise its SSM Policy with respect to affirmative defense provisions applicable to excess 

emissions during SSM events (as described in section V of the SNPR) and to apply its revised 

interpretation of the CAA to specific provisions in the SIPs of particular states (as described in 

section VII of the SNPR). 

For some of the affirmative defense provisions identified by the Petitioner, the EPA in 

the SNPR reproposed granting of the Petition but proposed a revised basis for its proposed 

findings of inadequacy and SIP calls. For other affirmative defense provisions identified by the 

Petitioner, the EPA in the SNPR reversed its prior proposed denial of the Petition, and it newly 

proposed findings of inadequacy and SIP calls. Further, for some affirmative defense provisions 

that were not explicitly identified by the Petitioner, the EPA in the SNPR proposed findings of 

inadequacy and SIP calls for additional affirmative defense provisions that were not explicitly 

identified by the Petitioner. 

B. Affected States in EPA Region I 

1. Maine 

As described in section IX.B.1 of the February 2013 proposal, the Petitioner first objected 

to a specific provision in the Maine SIP that provides an exemption for certain boilers from 

otherwise applicable SIP visible emission limits during startup and shutdown (06-096-101 Me. 

Code R. § 3). Second, the Petitioner objected to a provision that empowers the state to “exempt 

emissions occurring during periods of unavoidable malfunction or unplanned shutdown from 

civil penalty under section 349, subsection 2” (06-096-101 Me. Code R. § 4). 
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For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 06-096-101 Me. Code R. § 3 and 06-096-101 Me. Code R. § 4. 

Consequently, the EPA proposed to find that 06-096-101 Me. Code R. § 3 and 06-096-

101 Me. Code R. § 4 are substantially inadequate to meet CAA requirements and thus proposed 

to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to 06-096-101 Me. Code 

R. § 3 and 06-096-101 Me. Code R. § 4. Accordingly, the EPA is finding that these provisions 

are substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call to 

Maine to correct its SIP with respect to these provisions. This action is fully consistent with what 

the EPA proposed in February 2013. Please refer to the Response to Comment document 

available in the docket for this rulemaking concerning any comments specific to the Maine SIP 

that the EPA received and considered during the development of this rulemaking. 

2. New Hampshire 

As described in section IX.B.2 of the February 2013 proposal, the Petitioner objected to 

two generally applicable provisions in the New Hampshire SIP that allow emissions in excess of 

otherwise applicable SIP emission limitations during “malfunction or breakdown of any 

component part of the air pollution control equipment.” The Petitioner argued that the challenged 

provisions provide an automatic exemption for excess emissions during the first 48 hours when 

any component part of air pollution control equipment malfunctions (N.H. Code R. Env-A 

902.03) and further provide that “[t]he director may ... grant an extension of time or a temporary 

variance” for excess emissions outside of the initial 48-hour time period (N.H. Code R. Env-A 

902.04). Second, the Petitioner objected to two specific provisions in the New Hampshire SIP 

that provide source-specific exemptions for periods of startup for “any process, manufacturing 
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and service industry” (N.H. Code R. Env-A 1203.05) and for pre-June 1974 asphalt plants during 

startup, provided they are at 60-percent opacity for no more than 3 minutes (N.H. Code R. Env-A 

1207.02). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to N.H. Code R. Env-A 902.03, N.H. Code R. Env-A 1203.05 and N.H. 

Code R. Env-A 902.04. Also for reasons explained fully in the February 2013 proposal, the EPA 

proposed to deny the Petition with respect to N.H. Code R. Env-A 1207.02. 

Consequently, the EPA proposed to find that N.H. Code R. Env-A 902.03, N.H. Code R. 

Env-A 1203.05 and N.H. Code R. Env-A 902.04 are substantially inadequate to meet CAA 

requirements and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to N.H. Code R. Env-A 

902.03, N.H. Code R. Env-A 1203.05 and N.H. Code R. Env-A 902.04 and denying the Petition 

with respect to N.H. Code R. Env-A 1207.02. Accordingly, the EPA is finding that the 

provisions in N.H. Code R. Env-A 902.03, N.H. Code R. Env-A 1203.05 and N.H. Code R. EnvA 902.04 are substantially inadequate to meet CAA requirements and the EPA is thus issuing a 

SIP call with respect to these provisions. This action is fully consistent with what the EPA 

proposed in February 2013. Please refer to the Response to Comment document available in the 

docket for this rulemaking concerning any comments specific to the New Hampshire SIP that the 

EPA received and considered during the development of this rulemaking. 

3. Rhode Island 

As described in section IX.B.3 of the February 2013 proposal, the Petitioner objected to a 

generally applicable provision in the Rhode Island SIP that allows for a case-by-case petition 

procedure whereby a source can obtain a variance from state personnel under R.I. Gen. Laws § 
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23-23-15 to continue to operate during a malfunction of its control equipment that lasts more 

than 24 hours, if the source demonstrates that enforcement would constitute undue hardship 

without a corresponding benefit (25-4-13 R.I. Code R. § 16.2). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 25-4-13 R.I. Code R. § 16.2. 

Consequently, the EPA proposed to find that 25-4-13 R.I. Code R. § 16.2 is substantially 

inadequate to meet CAA requirements and thus proposed to issue a SIP call with respect to this 

provision. 

In this final action, the EPA is granting the Petition with respect to 25-4-13 R.I. Code R. 

§ 16.2. Accordingly, the EPA is finding that this provision is substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. This 

action is fully consistent with what the EPA proposed in February 2013. Please refer to the 

Response to Comment document available in the docket for this rulemaking concerning any 

comments specific to the Rhode Island SIP that the EPA received and considered during the 

development of this rulemaking. 

C. Affected State in EPA Region II 

New Jersey 

As described in section IX.C.1 of the February 2013 proposal, the Petitioner objected to 

two specific provisions in the New Jersey SIP that allow for automatic exemptions for excess 

emissions during emergency situations. The Petitioner objected to the first provision because it 

provides industrial process units that have the potential to emit sulfur compounds an exemption 

from the otherwise applicable sulfur emission limitations where “[t]he discharge from any stack 

or chimney [has] the sole function of relieving pressure of gas, vapor or liquid under abnormal 
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emergency conditions” (N.J. Admin. Code 7:27-7.2(k)(2)). The Petitioner objected to the second 

provision because it provides electric generating units (EGUs) an exemption from the otherwise 

applicable NOx emission limitations when the unit is operating at “emergency capacity,” also 

known as a “MEG alert,” which is statutorily defined as a period in which one or more EGUs is 

operating at emergency capacity at the direction of the load dispatcher in order to prevent or 

mitigate voltage reductions or interruptions in electric service, or both (N.J. Admin. Code 7:27-

19.1). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to N.J. Admin. Code 7:27-7.2(k)(2). Also for reasons explained fully in the 

February 2013 proposal, the EPA proposed to deny the Petition with respect to N.J. Admin. 

Code 7:27-19.1. 

Consequently, the EPA proposed to find that N.J. Admin. Code 7:27-7.2(k)(2) is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to N.J. Admin. Code 

7:27-7.2(k)(2) and denying the Petition with respect to N.J. Admin. Code 7:27-19.1. 

Accordingly, the EPA is finding that the provision in N.J. Admin. Code 7:27-7.2(k)(2) is 

substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with 

respect to this provision. This action is fully consistent with what the EPA proposed in February 

2013. Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the New Jersey SIP that the EPA received and 

considered during the development of this rulemaking. 

D. Affected States in EPA Region III 
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1. Delaware 

As described in section IX.D.1 of the February 2013 proposal, the Petitioner objected to 

seven provisions in the Delaware SIP that provide exemptions during startup and shutdown from 

the otherwise applicable SIP emission limitations. The seven source-specific and pollutantspecific provisions that provide exemptions during periods of startup and shutdown are: 7-1100-

1104 Del. Code Regs § 1.5 (Particulate Emissions from Fuel Burning Equipment); 7-1100-1105 

Del. Code Regs § 1.7 (Particulate Emissions from Industrial Process Operations); 7-1100-1108 

Del. Code Regs § 1.2 (Sulfur Dioxide Emissions from Fuel Burning Equipment); 7-1100-1109 

Del. Code Regs § 1.4 (Emissions of Sulfur Compounds From Industrial Operations); 7-1100-

1114 Del. Code Regs § 1.3 (Visible Emissions); 7-1100-1124 Del. Code Regs § 1.4 (Control of 

Volatile Organic Compound Emissions); and 7-1100-1142 Del. Code Regs § 2.3.5 (Specific 

Emission Control Requirements). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 7-1100-1104 Del. Code Regs § 1.5, 7-1100-1105 Del. Code Regs § 1.7, 

7-1100-1108 Del. Code Regs § 1.2, 7-1100-1109 Del. Code Regs § 1.4, 7-1100-1114 Del. Code 

Regs § 1.3, 7-1100-1124 Del. Code Regs § 1.4 and 7-1100-1142 Del. Code Regs § 2.3.5. 

Consequently, the EPA proposed to find that 7-1100-1104 Del. Code Regs § 1.5, 7-1100-

1105 Del. Code Regs § 1.7, 7-1100-1108 Del. Code Regs § 1.2, 7-1100-1109 Del. Code Regs § 

1.4, 7-1100-1114 Del. Code Regs § 1.3, 7-1100-1124 Del. Code Regs § 1.4 and 7-1100-1142 

Del. Code Regs § 2.3.5 are substantially inadequate to meet CAA requirements and thus 

proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to 7-1100-1104 Del. 

Code Regs § 1.5, 7-1100-1105 Del. Code Regs § 1.7, 7-1100-1108 Del. Code Regs § 1.2, 7-
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1100-1109 Del. Code Regs § 1.4, 7-1100-1114 Del. Code Regs § 1.3, 7-1100-1124 Del. Code 

Regs § 1.4 and 7-1100-1142 Del. Code Regs § 2.3.1.6 (updated to § 2.3.1.6 from earlier 

identification as § 2.3.5). Accordingly, the EPA is finding that these provisions are substantially 

inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with respect to 

these provisions. 

2. District of Columbia 

As described in section IX.D.2 of the February 2013 proposal, the Petitioner objected to 

five provisions in the District of Columbia (DC) SIP as being inconsistent with the CAA and the 

EPA’s SSM Policy. The Petitioner first objected to a generally applicable provision in the DC 

SIP that allows for discretionary exemptions during periods of maintenance or malfunction (D.C. 

Mun. Regs. tit. 20 § 107.3). Secondly, the Petitioner objected to the alternative limitations on 

stationary sources for visible emissions during periods of “start-up, cleaning, soot blowing, 

adjustment of combustion controls, or malfunction,” (D.C. Mun. Regs. tit. 20 § 606.1) and, for 

fuel-burning equipment placed in initial operation before January 1977, alternative limits for 

visible emissions during startup and shutdown (D.C. Mun. Regs. tit. 20 § 606.2). The Petitioner 

also objected to the exemption from emission limitations for emergency standby engines (D.C. 

Mun. Regs. tit. 20 § 805.1(c)(2)). Finally, the Petitioner objected to the provision in the DC SIP 

that provides an affirmative defense for violations of visible emission limitations during 

“unavoidable malfunction” (D.C. Mun. Regs. tit. 20 § 606.4). 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to D.C. Mun. Regs. tit. 20 § 107.3 and ’D.C. Mun. Regs. tit. 20 §§ 606.1 

and 606.2. Also for reasons explained in the February 2013 proposal, the EPA proposed to deny 

the Petition with respect to D.C. Mun. Regs. tit. 20 § 805.1(c)(2). Also for reasons explained in 
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the February 2013 proposal, the EPA proposed to grant the petition with respect to D.C. Mun. 

Regs. tit. 20 § 606.4 on the basis that it was not a permissible affirmative defense provision 

consistent with the requirements of the CAA as interpreted in the EPA’s SSM Policy at the time. 

Subsequently, for reasons explained in the SNPR, the EPA reproposed granting of the 

Petition with respect to the affirmative defense provision in D.C. Mun. Regs. tit. 20 § 606.4, but 

it proposed to revise the basis for the finding of substantial inadequacy and the SIP call for this 

provision. 

Consequently, the EPA proposed to find that D.C. Mun. Regs. tit. 20 § 107.3, D.C. Mun. 

Regs. tit. 20 §§ 606.1 and 606.2 and D.C. Mun. Regs. tit. 20 § 606.4 are substantially inadequate 

to meet CAA requirements and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to D.C. Mun. Regs. tit. 

20 § 107.3, D.C. Mun. Regs. tit. 20 §§ 606.1 and 606.2 and D.C. Mun. Regs. tit. 20 § 606.4 and 

is denying the Petition with respect to D.C. Mun. Regs. tit. 20 § 805.1(c)(2). Accordingly, the 

EPA is finding that the provisions in D.C. Mun. Regs. tit. 20 § 107.3, D.C. Mun. Regs. tit. 20 §§ 

606.1 and 606.2 and D.C. Mun. Regs. tit. 20 § 606.4 are substantially inadequate to meet CAA 

requirements and the EPA is thus issuing a SIP call to the District of Columbia to correct its SIP 

with respect to these provisions. This action is fully consistent with what the EPA proposed in 

February 2013 as revised in the SNPR. Please refer to the Response to Comment document 

available in the docket for this rulemaking concerning any comments specific to the DC SIP that 

the EPA received and considered during the development of this rulemaking. 

3. Virginia 

As described in section IX.D.3 of the February 2013 proposal, the Petitioner objected to a 

generally applicable provision in the Virginia SIP that allows for discretionary exemptions 
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during periods of malfunction (9 Va. Admin. Code § 5-20-180(G)). First, the Petitioner objected 

because this provision provides an exemption from the otherwise applicable SIP emission 

limitations. Second, the Petitioner objected to the discretionary exemption for excess emissions 

during malfunction because the provision gives the state the authority to determine whether a 

violation “shall be judged to have taken place.” Third, the Petitioner argued that while the 

regulation provides criteria, akin to an affirmative defense, by which the state must make such a 

judgment that the event is not a violation, the criteria “fall far short of EPA policy at the time” 

and the provision “fails to establish any procedure through which the criteria are to be 

evaluated.” 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 9 Va. Admin. Code § 5-20-180(G). Also for reasons explained in the 

February 2013 proposal, the EPA proposed to grant the Petition with respect to this provision on 

the basis that it was not a permissible affirmative defense provision consistent with the 

requirements of the CAA as interpreted in the EPA’s SSM Policy. 

Subsequently, for reasons explained in the SNPR, the EPA reproposed granting of the 

Petition with respect to 9 Va. Admin. Code § 5-20-180(G), but it proposed to revise the basis for 

the finding of substantial inadequacy and the SIP call for this provision. 

Consequently, the EPA proposed to find that 9 Va. Admin. Code § 5-20-180(G) is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to 9 Va. Admin. Code § 

5-20-180(G) and the EPA is thus issuing a SIP call with respect to this provision. This action is 

fully consistent with what the EPA proposed in February 2013 as revised in the SNPR. Please 
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refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Virginia SIP that the EPA received and considered 

during the development of this rulemaking. 

4. West Virginia 

As described in section IX.D.4 of the February 2013 proposal, the Petitioner made four 

types of objections identifying inadequacies regarding SSM provisions in West Virginia’s SIP. 

First, the Petitioner objected to three specific provisions in the West Virginia SIP that allow for 

automatic exemptions from emission limitations, standards, and monitoring and recordkeeping 

requirements for excess emission during startup, shutdown, or malfunction (W. Va. Code R. § 

45-2-9.1, W. Va. Code R. §45-7-10.3 and W. Va. Code R. §45-40-100.8). Second, the Petitioner 

objected to seven discretionary exemption provisions because these provisions provide 

exemptions from the otherwise applicable SIP emission limitations. The Petitioner noted that the 

provisions allow a state official to “grant an exception to the otherwise applicable visible 

emissions standards” due to “unavoidable shortage of fuel” or “any emergency situation or 

condition creating a threat to public safety or welfare” (W. Va. Code R. § 45-2-10.1), to permit 

excess emissions “due to unavoidable malfunctions of equipment” (W. Va. Code R. § 45-3-7.1, 

W. Va. Code R. § 45-5-13.1, W. Va. Code R. § 45-6-8.2, W. Va. Code R. § 45-7-9.1 and W. Va. 

Code R. § 45-10-9.1) and to permit exceedances where the limit cannot be “satisfied” because of 

“routine maintenance” or “unavoidable malfunction” (W. Va. Code R. §45-21-9.3). Third, the 

Petitioner objected to the alternative limit imposed on hot mix asphalt plants during periods of 

startup and shutdown in W. Va. Code R. § 45-3-3.2 because it was “not sufficiently justified” 

under the EPA’s SSM Policy regarding source category-specific rules. Fourth, the Petitioner 

objected to a discretionary provision allowing the state to approve an alternative visible emission 
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standard during startups and shutdowns for manufacturing processes and associated operations 

(W. Va. Code R. § 45-7-10.4). The Petitioner argued that such a provision “allows a decision of 

the state to preclude enforcement by EPA and citizens.” 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to W. Va. Code R. § 45-2-9.1, W. Va. Code R. § 45-7-10.3 and W. Va. 

Code R. § 45-40-100.8 on the basis that each of these provisions allows for automatic 

exemptions. Also for reasons explained in the February 2013 proposal, the EPA proposed to 

grant the Petition with respect to W. Va. Code R. § 45-2-10.1, W. Va. Code R. § 45-3-7.1, W. 

Va. Code R. § 45-5-13.1, W. Va. Code R. § 45-6-8.2, W. Va. Code R. § 45-7-9.1, W. Va. Code 

R. § 45-10-9.1 and W. Va. Code R. § 45-21-9.3 on the basis that these provisions allow for 

discretionary exemptions from otherwise applicable SIP emission limitations. Further, for 

reasons explained in the February 2013 proposal, the EPA proposed to grant the Petition with 

respect to W. Va. Code R. § 45-3-3.2, W. Va. Code R. § 45-2-10.2 and W. Va. Code R. § 45-7-

10.4. The W. Va. Code R. § 45-3-3.2 applies to a broad category of sources and is not narrowly 

limited to a source category that uses a specific control strategy, as required by the EPA’s SSM 

Policy interpreting the CAA. Similarly, W. Va. Code R. § 45-2-10.2 is inconsistent with the 

EPA’s SSM Policy interpreting the CAA because it is an alternative limit that applies during 

periods of maintenance, and such alternative limits are only permissible during periods of startup 

and shutdown.376 The W. Va. Code R. § 45-7-10.4 allows state officials the discretion to 

establish alternative visible emissions standards during startup and shutdown upon application. 

 

376 As explained in the February 2013 proposal, the Petitioner specifically focused on concern 

with W. Va. Code R. § 45-2-10.1, but the same issue affects W. Va. Code R. § 45-2-10.2, and so 

the EPA similarly proposed to issue a SIP call with respect to the latter provision. See 78 FR 

12459 at 12500, n.111. 
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Subsequently, for reasons explained fully in the SNPR, the EPA identified one 

affirmative defense provision in the West Virginia SIP in W. Va. Code R. § 45-2-9.4 that was 

not identified by the Petitioner, and the EPA proposed to make a finding of substantial 

inadequacy and to issue a SIP call for this provision. 

Consequently, the EPA proposed to find that W. Va. Code R. § 45-2-9.1, W. Va. Code R. 

§45-7-10.3, W. Va. Code R. §45-40-100.8, W. Va. Code R. § 45-2-10.1, W. Va. Code R. § 45-3-

7.1, W. Va. Code R. § 45-5-13.1, W. Va. Code R. § 45-6-8.2, W. Va. Code R. § 45-7-9.1, W. 

Va. Code R. § 45-10-9.1, W. Va. Code R. §45-21-9.3, W. Va. Code R. § 45-3-3.2 and W. Va. 

Code R. § 45-7-10.4, which are provisions identified by the Petitioner, and W. Va. Code R. § 45-

2-10.2 and W. Va. Code R. § 45-2-9.4, which are provisions identified by the EPA, are 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to the West Virginia SIP 

provisions identified by the Petitioner. Accordingly, the EPA is finding that the provisions in W. 

Va. Code R. § 45-2-9.1, W. Va. Code R. §45-7-10.3, W. Va. Code R. §45-40-100.8, W. Va. 

Code R. § 45-2-10.1, W. Va. Code R. § 45-3-7.1, W. Va. Code R. § 45-5-13.1, W. Va. Code R. § 

45-6-8.2, W. Va. Code R. § 45-7-9.1, W. Va. Code R. § 45-10-9.1, W. Va. Code R. §45-21-9.3, 

W. Va. Code R. § 45-3-3.2 and W. Va. Code R. § 45-7-10.4, which are provisions identified by 

the Petitioner, and W. Va. Code R. § 45-2-10.2 and W. Va. Code R. § 45-2-9.4, which are 

provisions identified by the EPA, are substantially inadequate to meet CAA requirements. The 

EPA is thus issuing a SIP call to West Virginia to correct its SIP with respect to these provisions. 

This action is fully consistent with what the EPA proposed in February 2013 as revised in the 

SNPR. Please refer to the Response to Comment document available in the docket for this 
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rulemaking concerning any comments specific to the West Virginia SIP that the EPA received 

and considered during the development of this rulemaking. 

E. Affected States and Local Jurisdictions in EPA Region IV 

1. Alabama 

As described in section IX.E.1 of the February 2013 proposal, the Petitioner objected to 

two generally applicable provisions in the Alabama SIP that allow for discretionary exemptions 

during startup, shutdown or load change (Ala Admin Code Rule 335-3-14-.03(1)(h)(1)), and 

during emergencies (Ala Admin Code Rule 335-3-14-.03(1)(h)(2)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Ala Admin Code Rule 335-3-14-.03(1)(h)(1) and Ala Admin Code Rule 

335-3-14-.03(1)(h)(2). 

Consequently, the EPA proposed to find that Ala Admin Code Rule 335-3-14-

.03(1)(h)(1) and Ala Admin Code Rule 335-3-14-.03(1)(h)(2) are substantially inadequate to 

meet CAA requirements and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to Ala Admin Code Rule 

335-3-14-.03(1)(h)(1) and Ala Admin Code Rule 335-3-14-.03(1)(h)(2). Accordingly, the EPA is 

finding that these provisions are substantially inadequate to meet CAA requirements and the 

EPA is thus issuing a SIP call with respect to these provision. This action is fully consistent with 

what the EPA proposed in February 2013. Please refer to the Response to Comment document 

available in the docket for this rulemaking concerning any comments specific to the Alabama 

SIP that the EPA received and considered during the development of this rulemaking. 

2. Florida 
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As described in section IX.E.2 of the February 2013 proposal, the Petitioner objected to 

three specific provisions in the Florida SIP that allow for generally applicable automatic 

exemptions for excess emissions during SSM (Fla. Admin. Code Ann Rule 62-201.700(1)), for 

fossil fuel steam generators during startup and shutdown (Fla. Admin. Code Ann Rule 62-

201.700(2)), and for such sources during boiler cleaning and load change (Fla. Admin. Code Ann 

Rule 62-201.700(3)). After objecting to the three provisions that create the exemptions, the 

Petitioner noted that the related provision in Fla. Admin. Code Ann Rule 62-201.700(4) reduces 

the potential scope of the exemptions in the other three provisions if the excess emissions at issue 

are caused entirely or in part by things such as poor maintenance but that it does not eliminate 

the impermissible exemptions. 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Fla. Admin. Code Ann Rule 62-201.700(1), Fla. Admin. Code Ann Rule 

62-201.700(2), Fla. Admin. Code Ann Rule 62-201.700(3) and Fla. Admin. Code Ann Rule 62-

201.700(4). 

Consequently, the EPA proposed to find that Fla. Admin. Code Ann Rule 62-201.700(1), 

Fla. Admin. Code Ann Rule 62-201.700(2), Fla. Admin. Code Ann Rule 62-201.700(3) and Fla. 

Admin. Code Ann Rule 62-201.700(4) are substantially inadequate to meet CAA requirements 

and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to Fla. Admin. Code 

Ann Rule 62-201.700(1), Fla. Admin. Code Ann Rule 62-201.700(2), Fla. Admin. Code Ann 

Rule 62-201.700(3) and Fla. Admin. Code Ann Rule 62-201.700(4). Accordingly, the EPA is 

finding that these provisions are substantially inadequate to meet CAA requirements and the 

EPA is thus issuing a SIP call with respect to these provisions. This action is fully consistent 
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with what the EPA proposed in February 2013. Please refer to the Response to Comment 

document available in the docket for this rulemaking concerning any comments specific to the 

Florida SIP that the EPA received and considered during the development of this rulemaking. 

3. Georgia 

As described in section IX.E.3 of the February 2013 proposal, the Petitioner objected to a 

provision in the Georgia SIP that provides for exemptions for excess emissions during SSM 

under certain circumstances (Ga. Comp. R. & Regs. 391-3-1-.02(2)(a)(7)). The Petitioner 

acknowledged that this provision of the Georgia SIP includes some conditions for when sources 

may be entitled to seek the exemption under state law, such as when the source has used “best 

operational practices” to minimize emissions during the SSM event. 

First, the Petitioner objected because the provision creates an exemption from the 

applicable emission limitations by providing that the excess emissions “shall be allowed” subject 

to certain conditions. Second, the Petitioner argued that although the provision provides some 

“substantive criteria,” the provision does not meet the criteria the EPA recommended at the time 

for an affirmative defense provision consistent with the requirements of the CAA in the EPA’s 

SSM Policy. Third, the Petitioner asserted that the provision is not a permissible “enforcement 

discretion” provision applicable only to state personnel, because it “is susceptible to 

interpretation as an enforcement exemption, precluding EPA and citizen enforcement as well as 

state enforcement.” 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Ga. Comp. R. & Regs. 391-3-1-.02(2)(a)(7). Also for reasons explained 

in the February 2013 proposal, the EPA proposed to grant the Petition with respect to this 

provision on the basis that it was not a permissible affirmative defense provision consistent with 
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the requirements of the CAA and the EPA’s recommendations in the EPA’s SSM Policy at the 

time. 

Subsequently, for reasons explained in the SNPR, the EPA reproposed granting of the 

Petition with respect to Ga. Comp. R. & Regs. 391-3-1-.02(2)(a)(7), but it proposed to revise the 

basis for the finding of substantial inadequacy and the SIP call for this provision. 

Consequently, the EPA proposed to find that Ga. Comp. R. & Regs. 391-3-1-.02(2)(a)(7) 

is substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to Ga. Comp. R. & Regs. 

391-3-1-.02(2)(a)(7). Accordingly, the EPA is finding that this provision is substantially 

inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with respect to this 

provision. This action is fully consistent with what the EPA proposed in February 2013 as 

revised in the SNPR. Please refer to the Response to Comment document available in the docket 

for this rulemaking concerning any comments specific to the Georgia SIP that the EPA received 

and considered during the development of this rulemaking. 

4. Kentucky 

As described in section IX.E.4 of the February 2013 proposal, the Petitioner objected to a 

generally applicable provision that allows discretionary exemptions from otherwise applicable 

SIP emission limitations in Kentucky’s SIP (401 KAR 50:055 §1(1)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 401 KAR 50:055 §1(1). 
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Consequently, the EPA proposed to find that 401 KAR 50:055 §1(1) is substantially 

inadequate to meet CAA requirements and thus proposed to issue a SIP call with respect to this 

provision. 

In this final action, the EPA is granting the Petition with respect to 401 KAR 50:055 

§1(1). Accordingly, the EPA is finding that this provision is substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. This 

action is fully consistent with what the EPA proposed in February 2013. Please refer to the 

Response to Comment document available in the docket for this rulemaking concerning any 

comments specific to the Kentucky SIP that the EPA received and considered during the 

development of this rulemaking. 

5. Kentucky: Jefferson County 

As described in section IX.E.5 of the February 2013 proposal, the Petitioner objected to a 

generally applicable provision in the Jefferson County Air Regulations 1.07 because it provided 

for discretionary exemptions from compliance with emission limitations during SSM. The 

provision required different demonstrations for exemptions for excess emissions during startup 

and shutdown (Regulation 1.07 § 3), malfunction (Regulation 1.07 § 4 and § 7) and emergency 

(Regulation 1.07 § 5 and § 7). Second, the Petitioner objected to the affirmative defense for 

emergencies in Jefferson County Air Regulations 1.07. 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to provisions in the Jefferson County Air Regulations 1.07. 

Subsequently, for reasons explained fully in the SNPR, the EPA reversed its prior 

proposed granting of the Petition with respect to Jefferson County Air Regulations 1.07. For 

Jefferson County, Kentucky, the provisions for which the EPA proposed in February 2013 to 
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grant the Petition were subsequently removed from the SIP. Thus, in the SNPR, the EPA 

proposed instead to deny the Petition.377 As explained in the SNPR, the state of Kentucky has 

revised the SIP provisions applicable to Jefferson County and eliminated the SIP inadequacies 

identified in the February 2013 proposal notice. The EPA has already approved the necessary 

SIP revisions. 378 Accordingly, the EPA’s final action on the Petition does not include a finding 

of substantial inadequacy and SIP call for Jefferson County, Kentucky. 

In this final action, the EPA is denying the Petition with respect to Jefferson County Air 

Regulations 1.07. This action is fully consistent with what the EPA proposed in February 2013 

as revised in the SNPR. Please refer to the Response to Comment document available in the 

docket for this rulemaking concerning any comments specific to the Kentucky SIP that the EPA 

received and considered during the development of this rulemaking. 

6. Mississippi 

As described in section IX.E.6 of the February 2013 proposal, the Petitioner objected to 

two generally applicable provisions in the Mississippi SIP that allow for affirmative defenses for 

violations of otherwise applicable SIP emission limitations during periods of upset, i.e., 

malfunctions (11-1-2 Miss. Code R. § 10.1) and unavoidable maintenance (11-1-2 Miss. Code R. 

§ 10.3). First, the Petitioner objected to both of these provisions based on its assertion that the 

CAA allows no affirmative defense provisions in SIPs. Second, the Petitioner asserted that even 

if affirmative defense provisions were permissible under the CAA, the affirmative defenses in 

these provisions “fall far short of the EPA policy at the time.” The Petitioner also objected to a 

 

377 See SNPR, 79 FR 55919 at 55925. 

378 See Approval and Promulgation of Implementation Plans; Kentucky; Approval of Revisions 

to the Jefferson County Portion of the Kentucky SIP; Emissions During Startups, Shutdowns, 

and Malfunctions, 79 FR 33101 (June 10, 2014). 
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generally applicable provision that provides an exemption from otherwise applicable SIP 

emission limitations during startup and shutdown (11-1-2 Miss. Code R. § 10.2). 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 11-1-2 Miss. Code R. § 10.1 and 11-1-2 Miss. Code R. § 10.3. Also for 

reasons explained in the February 2013 proposal, the EPA proposed to grant the petition with 

respect to these provisions on the basis that they were not appropriate as an affirmative defense 

provisions because they were inconsistent with fundamental requirements of the CAA. Also for 

reasons explained fully in the February 2013 proposal, the EPA proposed to grant the Petition 

with respect to 11-1-2 Miss. Code R. § 10.2. 

Subsequently, for reasons explained in the SNPR, the EPA reproposed granting of the 

Petition with respect to the affirmative defense provisions in 11-1-2 Miss. Code R. § 10.1 and 

11-1-2 Miss. Code R. § 10.3, but it proposed to revise the basis for the finding of substantial 

inadequacy and the SIP call for these provisions. 

Consequently, the EPA proposed to find that 11-1-2 Miss. Code R. § 10.1, 11-1-2 Miss. 

Code R. § 10.2 and 11-1-2 Miss. Code R. § 10.3 are substantially inadequate to meet CAA 

requirements and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to 11-1-2 Miss. Code R. 

§ 10.1, 11-1-2 Miss. Code R. § 10.2 and 11-1-2 Miss. Code R. § 10.3. Accordingly, the EPA is 

finding that these provisions are substantially inadequate to meet CAA requirements and the 

EPA is thus issuing a SIP call with respect to these provisions. This action is fully consistent 

with what the EPA proposed in February 2013 as revised in the SNPR. Please refer to the 

Response to Comment document available in the docket for this rulemaking concerning any 
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comments specific to the Mississippi SIP that the EPA received and considered during the 

development of this rulemaking. 

7. North Carolina 

As described in section IX.E.7 of the February 2013 proposal, the Petitioner objected to 

two generally applicable provisions in the North Carolina SIP that provide exemptions for 

emissions exceeding otherwise applicable SIP emission limitations at the discretion of the state 

agency during malfunctions (15A N.C. Admin. Code 2D.0535(c)) and during startup and 

shutdown (15A N.C. Admin. Code 2D.0535(g)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 15A N.C. Admin. Code 2D.0535(c) and 15A N.C. Admin. Code 

2D.0535(g). 

Consequently, the EPA proposed to find that 15A N.C. Admin. Code 2D.0535(c) and 

15A N.C. Admin. Code 2D.0535(g) are substantially inadequate to meet CAA requirements and 

thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to 15A N.C. Admin. 

Code 2D.0535(c) and 15A N.C. Admin. Code 2D.0535(g). Accordingly, the EPA is finding that 

these provisions are substantially inadequate to meet CAA requirements and the EPA is thus 

issuing a SIP call with respect to these provisions. This action is fully consistent with what the 

EPA proposed in February 2013. Please refer to the Response to Comment document available 

in the docket for this rulemaking concerning any comments specific to the North Carolina SIP 

that the EPA received and considered during the development of this rulemaking. 

8. North Carolina: Forsyth County 
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As described in section IX.E.8 of the February 2013 proposal, the Petitioner objected to 

two generally applicable provisions in the Forsyth County Code that provide exemptions for 

emissions exceeding otherwise applicable SIP emission limitations at the discretion of a local 

official during malfunctions (Forsyth County Code, ch. 3, 3D.0535(c)) and startup and shutdown 

(Forsyth County Code, ch. 3, 3D.0535(g)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Forsyth County Code, ch. 3, 3D.0535(c) and Forsyth County Code, ch. 3, 

3D.0535(g). 

Consequently, the EPA proposed to find that Forsyth County Code, ch. 3, 3D.0535(c) and 

Forsyth County Code, ch. 3, 3D.0535(g) are substantially inadequate to meet CAA requirements 

and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to Forsyth County Code, 

ch. 3, 3D.0535(c) and Forsyth County Code, ch. 3, 3D.0535(g). Accordingly, the EPA is finding 

that these provisions are substantially inadequate to meet CAA requirements and the EPA is thus 

issuing a SIP call with respect to these provisions. This action is fully consistent with what the 

EPA proposed in February 2013. Please refer to the Response to Comment document available 

in the docket for this rulemaking concerning any comments specific to the North Carolina SIP 

that the EPA received and considered during the development of this rulemaking. 

9. South Carolina 

As described in section IX.E.9 of the February 2013 proposal, the Petitioner objected to 

three provisions in the South Carolina SIP, arguing that they contained impermissible source 

category- and pollutant-specific exemptions. The Petitioner characterized these provisions as 

providing exemptions from opacity limits for fuel-burning operations for excess emissions that 
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occur during startup or shutdown (S.C. Code Ann. Regs. 61-62.5 St 1(C)), exemptions from NOx 

limits for special-use burners that are operated less than 500 hours per year (S.C. Code Ann. 

Regs. 61-62.5 St 5.2(I)(b)(14)) and exemptions from sulfur limits for kraft pulp mills for excess 

emissions that occur during SSM events (S.C. Code Ann. Regs. St 4(XI)(D)(4)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to S.C. Code Ann. Regs. 61-62.5 St 1(C) and S.C. Code Ann. Regs. St 

4(XI)(D)(4). Also for reasons explained fully in the February 2013 proposal, the EPA proposed 

to deny the Petition with respect to S.C. Code Ann. Regs. 61-62.5 St 5.2(I)(b)(14). 

Subsequently, for reasons explained fully in the SNPR, the EPA identified one 

affirmative defense provision in the South Carolina SIP in S.C. Code Ann. Regs. 62.1, Section 

II(G)(6) that was not identified by the Petitioner, and the EPA proposed to make a finding of 

substantial inadequacy and to issue a SIP call for this provision. 

Consequently, the EPA proposed to find that the provisions in S.C. Code Ann. Regs. 61-

62.5 St 1(C), S.C. Code Ann. Regs. St 4(XI)(D)(4) and S.C. Code Ann. Regs. 62.1, Section 

II(G)(6) are substantially inadequate to meet CAA requirements and thus proposed to issue a SIP 

call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to S.C. Code Ann. Regs. 

61-62.5 St 1(C), S.C. Code Ann. Regs. St 4(XI)(D)(4) and S.C. Code Ann. Regs. 62.1, Section 

II(G)(6) and denying the Petition with respect to S.C. Code Ann. Regs. 61-62.5 St 5.2(I)(b)(14). 

Accordingly, the EPA is finding that the provisions in S.C. Code Ann. Regs. 61-62.5 St 1(C), 

S.C. Code Ann. Regs. St 4(XI)(D)(4) and S.C. Code Ann. Regs. 62.1, Section II(G)(6) are 

substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with 

respect to these provisions. This action is fully consistent with what the EPA proposed in 
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February 2013 as revised in the SNPR. Please refer to the Response to Comment document 

available in the docket for this rulemaking concerning any comments specific to the South 

Carolina SIP that the EPA received and considered during the development of this rulemaking. 

10. Tennessee 

As described in section IX.E.10 of the February 2013 proposal, the Petitioner objected to 

three provisions in the Tennessee SIP. First, the Petitioner objected to two provisions that 

authorize a state official to decide whether to “excuse or proceed upon” (Tenn. Comp. R. & 

Regs. 1200-3-20-.07(1)) violations of otherwise applicable SIP emission limitations that occur 

during “malfunctions, startups, and shutdowns” (Tenn. Comp. R. & Regs. 1200-3-20-.07(3)). 

Second, the Petitioner objected to a provision that excludes excess visible emissions from the 

requirement that the state automatically issue a notice of violation for all excess emissions (Tenn. 

Comp. R. & Regs. 1200-3-5-.02(1)). This provision states that “due allowance may be made for 

visible emissions in excess of that permitted in this chapter which are necessary or unavoidable 

due to routine startup and shutdown conditions.” 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Tenn. Comp. R. & Regs. 1200-3-20-.07(1), Tenn. Comp. R. & Regs. 

1200-3-20-.07(3) and Tenn. Comp. R. & Regs. 1200-3-5-.02(1). 

Consequently, the EPA proposed to find that Tenn. Comp. R. & Regs. 1200-3-20-.07(1), 

Tenn. Comp. R. & Regs. 1200-3-20-.07(3) and Tenn. Comp. R. & Regs. 1200-3-5-.02(1) are 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to Tenn. Comp. R. & 

Regs. 1200-3-20-.07(1), Tenn. Comp. R. & Regs. 1200-3-20-.07(3) and Tenn. Comp. R. & Regs. 
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1200-3-5-.02(1). Accordingly, the EPA is finding that these provisions are substantially 

inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with respect to 

these provisions. This action is fully consistent with what the EPA proposed in February 2013. 

Please refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Tennessee SIP that the EPA received and considered 

during the development of this rulemaking. 

11. Tennessee: Knox County 

As described in section IX.E.11 of the February 2013 proposal, the Petitioner objected to 

a provision in the Knox County portion of the Tennessee SIP that bars evidence of a violation of 

SIP emission limitations from being used in a citizen enforcement action (Knox County 

Regulation 32.1(C)). The provision specifies that “[a] determination that there has been a 

violation of these regulations or orders issued pursuant thereto shall not be used in any law suit 

brought by any private citizen.” 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Knox County Regulation 32.1(C). For instance, the regulation was 

inconsistent with requirements related to credible evidence. 

Consequently, the EPA proposed to find that Knox County Regulation 32.1(C) is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to Knox County 

Regulation 32.1(C). Accordingly, the EPA is finding that this provision is substantially 

inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with respect to this 

provision. This action is fully consistent with what the EPA proposed in February 2013. Please 
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refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Tennessee SIP that the EPA received and considered 

during the development of this rulemaking. 

12. Tennessee: Shelby County 

As described in section IX.E.12 of the February 2013 proposal, the Petitioner objected to 

a provision in the Shelby County Code (Shelby County Code § 16-87) that addresses 

enforcement for excess emissions that occur during “malfunctions, startups, and shutdowns” by 

incorporating by reference the state’s provisions in Tenn. Comp. R. & Regs. 1200-3-20. Shelby 

County Code § 16-87 provides that “all such additions, deletions, changes and amendments as 

may subsequently be made” to Tennessee’s regulations will automatically become part of the 

Shelby County Code. 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Shelby County Code § 16-87. 

Consequently, the EPA proposed to find that Shelby County Code § 16-87 is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to Shelby County Code § 

16-87. Accordingly, the EPA is finding that this provision is substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. This 

action is fully consistent with what the EPA proposed in February 2013. Please refer to the 

Response to Comment document available in the docket for this rulemaking concerning any 

comments specific to the Tennessee SIP that the EPA received and considered during the 

development of this rulemaking. 
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F. Affected States in EPA Region V 

1. Illinois 

As described in section IX.F.1 of the February 2013 proposal, the Petitioner objected to 

three generally applicable provisions in the Illinois SIP which together have the effect of 

providing discretionary exemptions from otherwise applicable SIP emission limitations. The 

Petitioner noted that the provisions invite sources to request, during the permitting process, 

advance permission to continue to operate during a malfunction or breakdown, and, similarly to 

request advance permission to “violate” otherwise applicable emission limitations during startup 

(Ill. Admin. Code tit. 35 § 201.261). The Illinois SIP provisions establish criteria that a state 

official must consider before granting the advance permission to violate the emission limitations 

(Ill. Admin. Code tit. 35 § 201.262). However, the Petitioner asserted, the provisions state that, 

once granted, the advance permission to violate the emission limitations “shall be a prima facie 

defense to an enforcement action” (Ill. Admin. Code tit. 35 § 201.265). 

Further, the Petitioner objected to the use of the term “prima facie defense” in Ill. Admin. 

Code tit. 35 § 201.265, arguing that the term is “ambiguous in its operation.” The Petitioner 

argued that the provision is not clear regarding whether the defense is to be evaluated “in a 

judicial or administrative proceeding or whether the Agency determines its availability.” 

Allowing defenses to be raised in these undefined contexts, the Petitioner argued, is “inconsistent 

with the enforcement structure of the Clean Air Act.” 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Ill. Admin. Code tit. 35 § 201.261, Ill. Admin. Code tit. 35 § 201.262 and 

Ill. Admin. Code tit. 35 § 201.265. 
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Subsequently, for reasons explained fully in the SNPR, the EPA reproposed granting of 

the Petition with respect to the affirmative defense provisions in Ill. Admin. Code tit. 35 § 

201.261, Ill. Admin. Code tit. 35 § 201.262 and Ill. Admin. Code tit. 35 § 201.265, but it 

proposed to revise the basis for the finding of substantial inadequacy and the SIP call for these 

provisions. 

Consequently, the EPA proposed to find that Ill. Admin. Code tit. 35 § 201.261, Ill. 

Admin. Code tit. 35 § 201.262 and Ill. Admin. Code tit. 35 § 201.265 are substantially 

inadequate to meet CAA requirements and thus proposed to issue a SIP call with respect to these 

provisions. 

In this final action, the EPA is granting the Petition with respect to Ill. Admin. Code tit. 

35 § 201.261, Ill. Admin. Code tit. 35 § 201.262 and Ill. Admin. Code tit. 35 § 201.265. 

Accordingly, the EPA is finding that these provisions are substantially inadequate to meet CAA 

requirements and the EPA is thus issuing a SIP call with respect to these provisions. This action 

is fully consistent with what the EPA proposed in February 2013 as revised in the SNPR. Please 

refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Illinois SIP that the EPA received and considered 

during the development of this rulemaking. 

2. Indiana 

As described in section IX.F.2 of the February 2013 proposal, the Petitioner objected to a 

generally applicable provision in the Indiana SIP that allows for discretionary exemptions during 

malfunctions (326 Ind. Admin. Code 1-6-4(a)). The Petitioner noted that the provision is 

ambiguous because it states that excess emissions during malfunction periods “shall not be 

considered a violation” if the source demonstrates that a number of conditions are met (326 Ind. 
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Admin. Code 1-6-4(a)), but the provision does not specify to whom or in what forum such 

demonstration must be made. 

If the demonstration was required to have been made in a showing to the state, the 

Petitioner argued, the provision would give a state official the sole authority to determine that the 

excess emissions were not a violation and could thus be read to preclude enforcement by the 

EPA or citizens in the event that the state official elects not to treat the excess emissions as a 

violation. If instead, as the Petitioner noted, the demonstration was required to have been made 

in an enforcement context, the provision could be interpreted as providing an affirmative 

defense. 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 326 Ind. Admin. Code 1-6-4(a). 

Subsequently, for reasons explained fully in the SNPR, the EPA reproposed granting of 

the Petition with respect to 326 Ind. Admin. Code 1-6-4(a), but it proposed to revise the basis for 

the finding of substantial inadequacy and the SIP call for this provision. 

Consequently, the EPA proposed to find that 326 Ind. Admin. Code 1-6-4(a) is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to 326 Ind. Admin. Code 

1-6-4(a). Accordingly, the EPA is finding that this provision is substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. This 

action is fully consistent with what the EPA proposed in February 2013 as revised in the SNPR. 

Please refer to the Response to Comment document available in the docket for this rulemaking 
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concerning any comments specific to the Indiana SIP that the EPA received and considered 

during the development of this rulemaking. 

3. Michigan 

As described in section IX.F.3 of the February 2013 proposal, the Petitioner objected to a 

generally applicable provision in Michigan’s SIP, Mich. Admin. Code r. 336.1916, that provides 

for an affirmative defense to monetary penalties for violations of otherwise applicable SIP 

emission limitations during periods of startup and shutdown. 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Mich. Admin. Code r. 336.1916. 

Subsequently, for reasons explained fully in the SNPR, the EPA reproposed granting of 

the Petition with respect to the affirmative defense provision in Mich. Admin. Code r. 336.1916, 

but it proposed to revise the basis for the finding of substantial inadequacy and the SIP call for 

this provision. 

Consequently, the EPA proposed to find that Mich. Admin. Code r. 336.1916 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to Mich. Admin. Code r. 

336.1916. Accordingly, the EPA is finding that this provision is substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. This 

action is fully consistent with what the EPA proposed in February 2013 as revised in the SNPR. 

Please refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Michigan SIP that the EPA received and considered 

during the development of this rulemaking. 
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4. Minnesota 

As described in section IX.F.4 of the February 2013 proposal, the Petitioner objected to a 

provision in the Minnesota SIP that provides automatic exemptions for excess emissions 

resulting from flared gas at petroleum refineries when those flares are caused by SSM (Minn. R. 

7011.1415). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Minn. R. 7011.1415. 

Consequently, the EPA proposed to find that Minn. R. 7011.1415 is substantially 

inadequate to meet CAA requirements and thus proposed to issue a SIP call with respect to this 

provision. 

In this final action, the EPA is granting the Petition with respect to Minn. R. 7011.1415. 

Accordingly, the EPA is finding that this provision is substantially inadequate to meet CAA 

requirements and the EPA is thus issuing a SIP call with respect to this provision. This action is 

fully consistent with what the EPA proposed in February 2013. Please refer to the Response to 

Comment document available in the docket for this rulemaking concerning any comments 

specific to the Minnesota SIP that the EPA received and considered during the development of 

this rulemaking. 

5. Ohio 

As described in section IX.F.5 of the February 2013 proposal, the Petitioner objected to a 

generally applicable provision in the Ohio SIP that allows for discretionary exemptions during 

periods of scheduled maintenance (Ohio Admin. Code 3745-15-06(A)(3)). The Petitioner also 

objected to two source category-specific and pollutant-specific provisions that provide for 

discretionary exemptions during malfunctions (Ohio Admin. Code 3745-17-07(A)(3)(c) and 
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Ohio Admin. Code 3745-17-07(B)(11)(f)). The Petitioner also objected to a source categoryspecific provision in the Ohio SIP that allows for an automatic exemption from applicable 

emission limitations and requirements during periods of startup, shutdown, malfunction, or 

regularly scheduled maintenance activities (Ohio Admin. Code 3745-14-11(D)). Finally, the 

Petitioner objected to five provisions that contain exemptions for Hospital/Medical/Infectious 

Waste Incinerator (HMIWI) sources during startup, shutdown, and malfunction—Ohio Admin. 

Code 3745-75-02(E), Ohio Admin. Code 3745-75-02(J), Ohio Admin. Code 3745-75-03(I), Ohio 

Admin. Code 3745-75-04(K) and Ohio Admin. Code 3745-75-04(L). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Ohio Admin. Code 3745-15-06(A)(3), Ohio Admin. Code 3745-17-

07(A)(3)(c), Ohio Admin. Code 3745-17-07(B)(11)(f) and Ohio Admin. Code 3745-14-11(D). 

Also for reasons explained fully in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to Ohio Admin. Code 3745-75-02(E), Ohio Admin. Code 3745-75-02(J), 

Ohio Admin. Code 3745-75-03(I), Ohio Admin. Code 3745-75-04(K), and Ohio Admin. Code 

3745-75-04(L), on the basis that they are not part of the Ohio SIP and thus cannot represent a 

substantial inadequacy in the SIP. In addition, for reasons explained fully in the February 2013 

proposal, the EPA proposed to find that another provision, Ohio Admin. Code 3745-15-06(C), is 

substantially inadequate to meet CAA requirements and proposed to issue a SIP call with respect 

to this provision, even though the Petitioner did not request that the EPA evaluate this provision. 

As explained in the February 2013 proposal, the EPA determined that Ohio Admin. Code 3745-

15-06(C) was the regulatory mechanism in the SIP by which exemptions are granted in the two 

provisions to which the Petitioner did object. 
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Consequently, the EPA proposed to find that the provisions in Ohio Admin. Code 3745-

15-06(A)(3), Ohio Admin. Code 3745-17-07(A)(3)(c), Ohio Admin. Code 3745-17-07(B)(11)(f), 

Ohio Admin. Code 3745-14-11(D) and Ohio Admin. Code 3745-15-06(C) are substantially 

inadequate to meet CAA requirements and thus proposed to issue a SIP call with respect to these 

provisions. 

In this final action, the EPA is granting the Petition with respect to Ohio Admin. Code 

3745-15-06(A)(3), Ohio Admin. Code 3745-17-07(A)(3)(c), Ohio Admin. Code 3745-17-

07(B)(11)(f), Ohio Admin. Code 3745-14-11(D) and Ohio Admin. Code 3745-15-06(C) are 

substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with 

respect to these provisions. This action is fully consistent with what the EPA proposed in 

February 2013. Please refer to the Response to Comment document available in the docket for 

this rulemaking concerning any comments specific to the Ohio SIP that the EPA received and 

considered during the development of this rulemaking. 

G. Affected States in EPA Region VI 

1. Arkansas 

As described in section IX.G.1 of the February 2013 proposal, the Petitioner objected to 

two provisions in the Arkansas SIP. First, the Petitioner objected to a provision that provides an 

automatic exemption for excess emissions of VOC for sources located in Pulaski County that 

occur due to malfunctions (Reg. 19.1004(H)). Second, the Petitioner objected to a separate 

provision that provides a “complete affirmative defense” for excess emissions that occur during 

emergency conditions (Reg. 19.602). The Petitioner argued that this provision, which the state 

may have modeled after the EPA’s title V regulations, is impermissible because its application is 

not clearly limited to operating permits. 
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For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Reg. 19.1004(H) and Reg. 19.602. 

Subsequently, for reasons explained fully in the SNPR, the EPA reproposed granting of 

the Petition with respect to the affirmative defense provision in Reg. 19.602, but it proposed to 

revise the basis for the finding of substantial inadequacy and the SIP call for this provision. 

Consequently, the EPA proposed to find that Reg. 19.1004(H) and Reg. 19.602 are 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to Reg. 19.1004(H) and 

Reg. 19.602. Accordingly, the EPA is finding that these provisions are substantially inadequate 

to meet CAA requirements and the EPA is thus issuing a SIP call with respect to these 

provisions. This action is fully consistent with what the EPA proposed in February 2013 as 

revised in the SNPR. Please refer to the Response to Comment document available in the docket 

for this rulemaking concerning any comments specific to the Arkansas SIP that the EPA received 

and considered during the development of this rulemaking. 

2. Louisiana 

 As described in section IX.G.2 of the February 2013 proposal, the Petitioner objected to 

several provisions in the Louisiana SIP that allow for automatic and discretionary exemptions 

from SIP emission limitations during various situations, including startup, shutdown, 

maintenance and malfunctions. First, the Petitioner objected to provisions that provide automatic 

exemptions for excess emissions of VOC from wastewater tanks (LAC 33:III.2153(B)(1)(i)) and 

excess emissions of NOx from certain sources within the Baton Rouge Nonattainment Area 

(LAC 33:III.2201(C)(8)). The LAC 33:III.2153(B)(1)(i) provides that control devices “shall not 
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be required” to meet emission limitations “during periods of malfunction and maintenance on the 

devices for periods not to exceed 336 hours per year.” Similarly, LAC 33:III.2201(C)(8) 

provides that certain sources “are exempted” from emission limitations “during start-up and 

shutdown . . . or during a malfunction.” Second, the Petitioner objected to provisions that provide 

discretionary exemptions to various emission limitations. Three of these provisions provide 

discretionary exemptions from otherwise applicable SO2 and visible emission limitations in the 

Louisiana SIP for excess emissions that occur during certain startup and shutdown events (LAC 

33:III.1107, LAC 33:III.1507(A)(1) and LAC 33:III.1507(B)(1)), while the other two provide 

such exemptions for excess emissions from nitric acid plants during startups and “upsets” (LAC 

33:III.2307(C)(1)(a) and LAC 33:III.2307(C)(2)(a)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to LAC 33:III.2153(B)(1)(i) and LAC 33:III.2201(C)(8) on the basis that 

these provisions allow for automatic exemptions for excess emissions from otherwise applicable 

SIP emission limitations. Also for reasons explained fully in the February 2013 proposal, the 

EPA proposed to grant the Petition with respect to LAC 33:III.1107(A), LAC 33:III.1507(A)(1), 

LAC 33:III.1507(B)(1), LAC 33:III.2307(C)(1)(a) and LAC 33:III.2307(C)(2)(a) on the basis 

that these provisions allow impermissible discretionary exemptions. 

Consequently, the EPA proposed to find that LAC 33:III.2153(B)(1)(i), LAC 

33:III.2201(C)(8), LAC 33:III.1107(A), LAC 33:III.1507(A)(1), LAC 33:III.1507(B)(1), LAC 

33:III.2307(C)(1)(a) and LAC 33:III.2307(C)(2)(a) are substantially inadequate to meet CAA 

requirements and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to LAC 

33:III.2153(B)(1)(i), LAC 33:III.2201(C)(8), LAC 33:III.1107(A), LAC 33:III.1507(A)(1), LAC 
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33:III.1507(B)(1), LAC 33:III.2307(C)(1)(a) and LAC 33:III.2307(C)(2)(a). Accordingly, the 

EPA is finding that these provisions are substantially inadequate to meet CAA requirements and 

the EPA is thus issuing a SIP call with respect to these provisions. This action is fully consistent 

with what the EPA proposed in February 2013. Please refer to the Response to Comment 

document available in the docket for this rulemaking concerning any comments specific to the 

Louisiana SIP that the EPA received and considered during the development of this rulemaking. 

3. New Mexico 

As described in section IX.G.3 of the February 2013 proposal, the Petitioner objected to 

three provisions in the New Mexico SIP that provide affirmative defenses for excess emissions 

that occur during malfunctions (20.2.7.111 NMAC), during startup and shutdown (20.2.7.112 

NMAC) and during emergencies (20.2.7.113 NMAC). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 20.2.7.111 NMAC, 20.2.7.112 NMAC and 20.2.7.113 NMAC. 

Subsequently, for reasons explained fully in the SNPR, the EPA reproposed granting of 

the Petition with respect to the affirmative defense provisions in 20.2.7.111 NMAC, 20.2.7.112 

NMAC and 20.2.7.113 NMAC, but it proposed to revise the basis for the finding of substantial 

inadequacy and the SIP call for these provisions. 

Consequently, the EPA proposed to find that the provisions in 20.2.7.111 NMAC, 

20.2.7.112 NMAC and 20.2.7.113 NMAC are substantially inadequate to meet CAA 

requirements and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to 20.2.7.111 NMAC, 

20.2.7.112 NMAC and 20.2.7.113 NMAC. Accordingly, the EPA is finding that these provisions 

are substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call 
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with respect to these provisions. This action is fully consistent with what the EPA proposed in 

February 2013 as revised in the SNPR. Please refer to the Response to Comment document 

available in the docket for this rulemaking concerning any comments specific to the New Mexico 

SIP that the EPA received and considered during the development of this rulemaking. 

4. New Mexico: Albuquerque-Bernalillo County 

The Petitioner did not identify any provisions in the SIP for the state of New Mexico that 

specifically apply in the Albuquerque-Bernalillo County area, which is why this area was not 

explicitly addressed in the February 2013 proposal. 

Subsequently, for reasons explained fully in the SNPR, the EPA ’identified three 

affirmative defense provisions in the SIP for the state of New Mexico that apply in the 

Albuquerque-Bernalillo County area, and the EPA proposed to make a finding of substantial 

inadequacy and to issue a SIP call for these provisions. These provisions provide affirmative 

defenses available to sources for excess emissions that occur during malfunctions (20.11.49.16.A 

NMAC), during startup and shutdown (20.11.49.16.B NMAC) and during emergencies 

(20.11.49.16.C NMAC). 

In this final action, the EPA is finding that the provisions in 20.11.49.16.A NMAC, 

20.11.49.16.B NMAC and 20.11.49.16.C NMAC are substantially inadequate to meet CAA 

requirements and the EPA is thus issuing a SIP call with respect to these provisions. The EPA 

notes that removal of 20.11.49.16.A NMAC, 20.11.49.16.B NMAC and 20.11.49.16.C NMAC 

from the SIP will render 20.11.49.16.D NMAC, 20.11.49.16.E, 20.11.49.15.B (15) (concerning 

reporting by a source of intent to assert an affirmative defense for a violation), a portion of 

20.11.49.6 NMAC (concerning the objective of establishing affirmative defense provisions) and 

20.11.49.18 NMAC (concerning actions where a determination has been made under 
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20.11.49.16.E NMAC) superfluous and no longer operative, and the EPA thus recommends that 

these provisions be removed as well. This action is fully consistent with what the EPA proposed 

in the SNPR. Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the New Mexico SIP that the EPA received and 

considered during the development of this rulemaking. 

5. Oklahoma 

As described in section IX.G.4 of the February 2013 proposal, the Petitioner objected to 

two provisions in the Oklahoma SIP that together allow for discretionary exemptions from 

emission limitations during startup, shutdown, maintenance and malfunctions (OAC 252:100-9-

3(a) and OAC 252:100-9-3(b)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to OAC 252:100-9-3(a) and OAC 252:100-9-3(b). 

Consequently, the EPA proposed to find that OAC 252:100-9-3(a) and OAC 252:100-9-

3(b) are substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call 

with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to OAC 252:100-9-3(a) 

and OAC 252:100-9-3(b). Accordingly, the EPA is finding that these provisions are substantially 

inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with respect to 

these provisions. This action is fully consistent with what the EPA proposed in February 2013. 

Please refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Oklahoma SIP that the EPA received and considered 

during the development of this rulemaking. 

6. Texas 
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The Petitioner did not identify in the June 2011 petition any provisions in the SIP for the 

state of Texas, which is why this state was not explicitly addressed in the February 2013 

proposal. 

Subsequently, for reasons explained fully in the SNPR, the EPA identified four 

affirmative defense provisions in the SIP for the state of Texas, and the EPA proposed to make a 

finding of substantial inadequacy and to issue a SIP call for these provisions. These provisions 

provide affirmative defenses available to sources for excess emissions that occur during upsets 

(30 TAC 101.222(b)), unplanned events (30 TAC 101.222(c)), upsets with respect to opacity 

limits (30 TAC 101.222(d)) and unplanned events with respect to opacity limits (30 TAC 

101.222(e)). 

In this final action, the EPA is finding that the provisions in 30 TAC 101.222(b), 30 TAC 

101.222(c), 30 TAC 101.222(d) and 30 TAC 101.222(e) are substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to these provisions. This 

action is fully consistent with what the EPA proposed in the SNPR. Please refer to the Response 

to Comment document available in the docket for this rulemaking concerning any comments 

specific to the Texas SIP that the EPA received and considered during the development of this 

rulemaking. 

H. Affected States in EPA Region VII 

1. Iowa 

As described in section IX.H.1 of the February 2013 proposal, the Petitioner objected to a 

specific provision in the Iowa SIP that allows for automatic exemptions from otherwise 

applicable SIP emission limitations during periods of startup, shutdown or cleaning of control 

equipment (Iowa Admin. Code r. 567-24.1(1)). Also, the Petitioner objected to a provision that 
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empowers the state to exercise enforcement discretion for violations of the otherwise applicable 

SIP emission limitations during malfunction periods (Iowa Admin. Code r. 567-24.1(4)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Iowa Admin. Code. R. 567-24.1(1) on the basis that this provision allows 

for exemptions from the otherwise applicable SIP emission limitations. Also for reasons 

explained fully in the February 2013 proposal, the EPA proposed to deny the Petition with 

respect to Iowa Admin. Code r. 567-24.1(4) on the basis that the provision is on its face clearly 

applicable only to Iowa state enforcement personnel and that the provision thus could not 

reasonably be read by a court to foreclose enforcement by the EPA or through a citizen suit 

where Iowa state personnel elect to exercise enforcement discretion. 

Consequently, the EPA proposed to find that Iowa Admin. Code r. 567-24.1(1) is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to Iowa Admin. Code r. 

567-24.1(1). Accordingly, the EPA is finding that this provision is substantially inadequate to 

meet CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. 

This action is fully consistent with what the EPA proposed in February 2013. Please refer to the 

Response to Comment document available in the docket for this rulemaking concerning any 

comments specific to the Iowa SIP that the EPA received and considered during the development 

of this rulemaking. 

2. Kansas 

As described in section IX.H.2 of the February 2013 proposal, the Petitioner objected to 

three provisions in the Kansas SIP that allow for exemptions for excess emissions during 
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malfunctions and necessary repairs (K.A.R. § 28-19-11(A)), scheduled maintenance (K.A.R. § 

28-19-11(B)), and certain routine modes of operation (K.A.R. § 28-19-11(C)). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to K.A.R. § 28-19-11(A), K.A.R. § 28-19-11(B) and K.A.R. § 28-19-11(C). 

Consequently, the EPA proposed to find that K.A.R. § 28-19-11(A), K.A.R. § 28-19-

11(B) and K.A.R. § 28-19-11(C) are substantially inadequate to meet CAA requirements and 

thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to K.A.R. § 28-19-

11(A), K.A.R. § 28-19-11(B) and K.A.R. § 28-19-11(C). Accordingly, the EPA is finding that 

these provisions are substantially inadequate to meet CAA requirements and the EPA is thus 

issuing a SIP call with respect to these provisions. This action is fully consistent with what the 

EPA proposed in February 2013. Please refer to the Response to Comment document available 

in the docket for this rulemaking concerning any comments specific to the Kansas SIP that the 

EPA received and considered during the development of this rulemaking. 

3. Missouri 

As described in section IX.H.3 of the February 2013 proposal, the Petitioner objected to 

two provisions in the Missouri SIP that could be interpreted to provide discretionary exemptions. 

The first provides exemptions for visible emissions exceeding otherwise applicable SIP opacity 

limitations (Mo. Code Regs. Ann. tit 10, § 10-6.220(3)(C)). The second provides authorization to 

state personnel to decide whether excess emissions “warrant enforcement action” where a source 

submits information to the state showing that such emissions were “the consequence of a 

malfunction, start-up or shutdown.” (Mo. Code Regs. Ann. tit 10, § 10-6.050(3)(C)). 
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For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Mo. Code Regs. Ann. tit 10, § 10-6.220(3)(C) on the basis that this 

provision could be read to allow for exemptions from the otherwise applicable SIP emission 

limitations through a state official’s unilateral exercise of discretionary authority that is 

insufficiently bounded and includes no additional public process at the state or federal level. 

Also for reasons explained fully in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to Mo. Code Regs. Ann. tit 10, § 10-6.050(3)(C) on the basis that the 

provision is on its face clearly applicable only to Missouri state enforcement personnel and that 

the provision thus could not reasonably be read by a court to foreclose enforcement by the EPA 

or through a citizen suit where Missouri state personnel elect to exercise enforcement discretion 

Consequently, the EPA proposed to find that the provision in Mo. Code Regs. Ann. tit 10, 

§ 10-6.220(3)(C) is substantially inadequate to meet CAA requirements and thus proposed to 

issue a SIP call with respect to this provision. 

In this final action, the EPA is granting the Petition with respect to Mo. Code Regs. Ann. 

tit 10, § 10-6.220(3)(C). Accordingly, the EPA is finding that this provision is substantially 

inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with respect to this 

provision. This action is fully consistent with what the EPA proposed in February 2013. Please 

refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Missouri SIP that the EPA received and considered 

during the development of this rulemaking. 

4. Nebraska 

As described in section IX.H.4 of the February 2013 proposal, the Petitioner objected to 

two provisions in the Nebraska SIP. First, the Petitioner objected to a generally applicable 
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provision that provides authorization to state personnel to decide whether excess emissions 

“warrant enforcement action” where a source submits information to the state showing that such 

emissions were “the result of a malfunction, start-up or shutdown” (Neb. Admin. Code Title 129 

§ 11-35.001). Second, the Petitioner objected to a specific provision in Nebraska state law that 

contains exemptions for excess emissions at hospital/medical/infectious waste incinerators 

(HMIWI) during SSM (Neb. Admin. Code Title 129 § 18-004.02). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to Neb. Admin. Code Title 129 § 11-35.001. Also for reasons explained 

fully in the February 2013 proposal, the EPA proposed to deny the Petition with respect to Neb. 

Admin. Code Title 129 § 18-004.02 on the basis that this regulation is not part of the Nebraska 

SIP and thus cannot represent an inadequacy in the SIP. 

In this final action, the EPA is denying the Petition with respect to Neb. Admin. Code 

Title 129, Chapter 35, Section 001 (correction to citation, as per comment received from 

Nebraska DEQ, from earlier identification as Neb. Admin. Code Title 129 § 11-35.001) and Neb. 

Admin. Code Title 129 § 18-004.02. 

This action is fully consistent with what the EPA proposed in February 2013. Please refer 

to the Response to Comment document available in the docket for this rulemaking concerning 

any other comments specific to the Nebraska SIP that the EPA received and considered during 

the development of this rulemaking. 

5. Nebraska: Lincoln-Lancaster 

As described in section IX.H.5 of the February 2013 proposal, the Petitioner objected to a 

generally applicable provision in the Lincoln-Lancaster County Air Pollution Control Program 

(Art. 2 § 35), which governs the Lincoln-Lancaster County Air Pollution Control District of 
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Nebraska, that is parallel “in all aspects pertinent to this analysis” to Neb. Admin. Code Title 129 

§ 11-35.001. (Note that as per comment subsequently received from Nebraska DEQ, the correct 

citation is Neb. Admin. Code Title 129, Chapter 35, Section 001.) 

For reasons explained fully in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to Art. 2 § 35, on the basis that Art. 2 § 35 is not part of the SIP. 

In this final action, the EPA is denying the Petition with respect to Art. 2 § 35. This 

action is fully consistent with what the EPA proposed in February 2013. Please refer to the 

Response to Comment document available in the docket for this rulemaking concerning any 

other comments specific to the Nebraska SIP that the EPA received and considered during the 

development of this rulemaking. 

I. Affected States in EPA Region VIII 

1. Colorado 

As described in section IX.I.1 of the February 2013 proposal, the Petitioner objected to 

two affirmative defense provisions in the Colorado SIP that provide for affirmative defenses to 

qualifying sources during malfunctions (5 Colo. Code Regs § 1001-2(II.E)) and during periods 

of startup and shutdown (5 Colo. Code Regs § 1001-2(II.J)). 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to 5 Colo. Code Regs § 1001-2(II.J). Also for reasons explained in the 

February 2013 proposal, the EPA proposed to deny the Petition with respect to 5 Colo. Code 

Regs § 1001-2(II.E) on the basis that it included an affirmative defense applicable to malfunction 

events that was consistent with the requirements of the CAA as interpreted by the EPA in the 

1999 SSM Guidance. 
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Subsequently, for reasons explained fully in the SNPR, the EPA reproposed granting of 

the Petition with respect to the affirmative defense provision in 5 Colo. Code Regs § 1001-2(II.J) 

applicable to startup and shutdown, but it proposed to revise the basis for the finding of 

substantial inadequacy and the SIP call for this provision. Also for reasons explained in the 

SNPR, the EPA reversed its prior proposed denial of the Petition with respect to the affirmative 

defense provision 5 Colo. Code Regs § 1001-2(II.E) applicable to malfunctions. 

Consequently, the EPA proposed to find that the provisions in 5 Colo. Code Regs § 1001-

2(II.J) and 5 Colo. Code Regs § 1001-2(II.E) are substantially inadequate to meet CAA 

requirements and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to 5 Colo. Code Regs § 

1001-2(II.J) and 5 Colo. Code Regs § 1001-2(II.E). Accordingly, the EPA is finding that the 

provisions in 5 Colo. Code Regs § 1001-2(II.J) and 5 Colo. Code Regs § 1001-2(II.E) are 

substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call to 

Colorado to correct its SIP with respect to these provisions. This action is fully consistent with 

what the EPA proposed in February 2013 as revised in the SNPR. Please refer to the Response to 

Comment document available in the docket for this rulemaking concerning any comments 

specific to the Colorado SIP that the EPA received and considered during the development of 

this rulemaking. 

2. Montana 

As described in section IX.I.2 of the February 2013 proposal, the Petitioner objected to 

an exemption from otherwise applicable emission limitations for aluminum plants during startup 

and shutdown (Montana Admin. R 17.8.334). 
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For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to ARM 17.8.334. 

Consequently, the EPA proposed to find that ARM 17.8.334 is substantially inadequate 

to meet CAA requirements and thus proposed to issue a SIP call with respect to this provision. 

In this final action, the EPA is granting the Petition with respect to ARM 17.8.334. 

Accordingly, the EPA is finding that ARM 17.8.334 is substantially inadequate to meet CAA 

requirements and the EPA is thus issuing a SIP call with respect to this provision. This action is 

fully consistent with what the EPA proposed in February 2013. Please refer to the Response to 

Comment document available in the docket for this rulemaking concerning any comments 

specific to the Montana SIP that the EPA received and considered during the development of this 

rulemaking. 

3. North Dakota 

As described in section IX.I.3 of the February 2013 proposal, the Petitioner objected to 

two provisions in the North Dakota SIP that create exemptions from otherwise applicable 

emission limitations. The first provision creates exemptions from a number of cross-referenced 

opacity limits “where the limits specified in this article cannot be met because of operations and 

processes such as, but not limited to, oil field service and drilling operations, but only so long as 

it is not technically feasible to meet said specifications” (N.D. Admin. Code § 33-15-03-04(4)). 

The second provision creates an implicit exemption for “temporary operational breakdowns or 

cleaning of air pollution equipment” if the source meets certain conditions (N.D. Admin. Code § 

33-15-05-01(2)(a)(1)). 

For reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to N.D. Admin. Code 33-15-03-04.4 (cited in the Petition as N.D. Admin. 
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Code § 33-15-03-04(4)) and also with respect to a provision to which the Petitioner cited but did 

not explicitly object, N.D. Admin. Code 33-15-03-04.3 (cited in the Petition as N.D. Admin. 

Code § 33-15-03-04(3)). Also for reasons explained in the February 2013 proposal, the EPA 

proposed to grant the Petition with respect to N.D. Admin. Code 33-15-05-01.2a(1) (cited in the 

Petition as N.D. Admin. Code § 33-15-05-01(2)(a)(1)). 

Subsequently, the state of North Dakota removed N.D. Admin. Code 33-15-03-04.4 and 

N.D. Admin. Code 33-15-05-01.2.a(1) and eliminated the SIP inadequacies with respect to those 

two of the three provisions identified in the February 2013 proposal notice. The EPA has already 

approved the necessary SIP revisions for those two provisions.379 Thus, the EPA’s final action on 

the Petition does not need to include a finding of substantial inadequacy and SIP call for those 

two provisions. 

In this final action, the EPA is granting the Petition with respect to N.D. Admin. Code 

33-15-03-04.3 and denying the Petition with respect to N.D. Admin. Code 33-15-03-04.4 and 

N.D. Admin. Code 33-15-05-01.2.a(1). Accordingly, the EPA is finding that the provision in 

N.D. Admin. Code 33-15-03-04.3 is substantially inadequate to meet CAA requirements and the 

EPA is thus issuing a SIP call to North Dakota to correct its SIP with respect to this provision. 

This action is fully consistent with what the EPA proposed in February 2013 with respect to this 

provision. Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the North Dakota SIP that the EPA received 

and considered during the development of this rulemaking. 

4. South Dakota 

 

379 See “Approval and Promulgation of Implementation Plans, North Dakota, Revisions to the 

Air Pollution Control Rules,” 79 FR 53045 (October 21, 2014). 
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As described in section IX.I.4 of the February 2013 proposal, the Petitioner objected to a 

provision in the South Dakota SIP that creates exemptions from otherwise applicable SIP 

emission limitations (S.D. Admin, R. 74:36:12:02(3)). The Petitioner asserted that the provision 

imposes visible emission limitations on sources but explicitly excludes emissions that occur “for 

brief periods during such operations as soot blowing, start-up, shut-down, and malfunctions.” 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to S.D. Admin, R. 74:36:12:02(3). 

Consequently, the EPA proposed to find that S.D. Admin, R. 74:36:12:02(3) is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to S.D. Admin, R. 

74:36:12:02(3). Accordingly, the EPA is finding that S.D. Admin, R. 74:36:12:02(3) is 

substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with 

respect to this provision. This action is fully consistent with what the EPA proposed in February 

2013. Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the South Dakota SIP that the EPA received 

and considered during the development of this rulemaking. 

5. Wyoming 

As described in section IX.I.5 of the February 2013 proposal, the Petitioner objected to a 

specific provision in the Wyoming SIP that provides an exemption for excess PM emissions 

from diesel engines during startup, malfunction and maintenance (WAQSR Chapter 3, section 

2(d), cited as ENV-AQ-1 Wyo. Code R. § 2(d) in the Petition). The provision exempts emission 

of visible air pollutants from diesel engines from applicable SIP limitations “during a reasonable 
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period of warmup following a cold start or where undergoing repairs and adjustment following 

malfunction.” 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to WAQSR Chapter 3, section 2(d) (cited as ENV-AQ-1 Wyo. Code R. § 

2(d) in the Petition). 

Subsequently, the state of Wyoming revised WAQSR Chapter 3, section 2(d) and 

eliminated the SIP inadequacies identified in the February 2013 proposal notice with respect to 

this provision. The EPA has already approved the necessary SIP revision for this provision.380

Thus, the EPA’s final action on the Petition does not need to include a finding of substantial 

inadequacy and SIP call for this provision. 

In this final action, the EPA is denying the Petition with respect to WAQSR Chapter 3, 

section 2(d). Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the Wyoming SIP that the EPA received and 

considered during the development of this rulemaking. 

J. Affected States and Local Jurisdictions in EPA Region IX 

1. Arizona 

As described in section IX.J.1 of the February 2013 proposal, the Petitioner objected to 

two provisions in the Arizona Department of Air Quality’s (ADEQ) Rule R18-2-310, which 

provide affirmative defenses for excess emissions during malfunctions (AAC Section R18-2-

310(B)) and for excess emissions during startup or shutdown (AAC Section R18-2-310(C)). 

 

380 See “Approval and Promulgation of Implementation Plans; Wyoming; Revisions to the Air 

Quality Standards and Regulations,” 79 FR 62859 (October 21, 2014). 
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For reasons explained in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to AAC Section R18-2-310(B) on the basis that it included an affirmative 

defense applicable to malfunction events that was consistent with the CAA as interpreted by the 

EPA in the 1999 SSM Guidance. 

Also for reasons explained in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to AAC Section R18-2-310(C). 

Subsequently, for reasons explained fully in the SNPR, the EPA reversed its prior 

proposed denial of the Petition with respect to the affirmative defense provision AAC Section 

R18-2-310(B) applicable to malfunctions. Also for reasons explained in the SNPR, the EPA 

reproposed granting of the Petition with respect to the affirmative defense provision in AAC 

Section R18-2-310(C) applicable to startup and shutdown, but it proposed to revise the basis for 

the finding of substantial inadequacy and the SIP call for this provision. 

Consequently, the EPA proposed to find that the provisions in AAC Section R18-2-

310(B) and AAC Section R18-2-310(C) are substantially inadequate to meet CAA requirements 

and thus proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to AAC Section R18-2-

310(B) and AAC Section R18-2-310(C). Accordingly, the EPA is finding that the provisions in 

AAC Section R18-2-310(B) and AAC Section R18-2-310(C) are substantially inadequate to 

meet CAA requirements and the EPA is thus issuing a SIP call with respect to these provisions. 

This action is fully consistent with what the EPA proposed in February 2013 as revised in the 

SNPR. Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the Arizona SIP that the EPA received and 

considered during the development of this rulemaking. 
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2. Arizona: Maricopa County 

As described in section IX.J.2 of the February 2013 proposal, the Petitioner objected to 

two provisions in the Maricopa County Air Pollution Control Regulations that provide 

affirmative defenses for excess emissions during malfunctions (Maricopa County Air Pollution 

Control Regulation 3, Rule 140, §401) and for excess emissions during startup or shutdown 

(Maricopa County Air Pollution Control Regulation 3, Rule 140, §402). These provisions in 

Maricopa County Air Quality Department (MCAQD) Rule 140 are similar to the affirmative 

defense provisions in ADEQ R18-2-310. 

For reasons explained in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to Maricopa County Air Pollution Control Regulation 3, Rule 140, §401 on 

the basis that it included an affirmative defense applicable to malfunction events that was 

consistent with the CAA as interpreted by the EPA in the 1999 SSM Guidance. Also for reasons 

explained in the February 2013 proposal, the EPA proposed to grant the Petition with respect to 

Maricopa County Air Pollution Control Regulation 3, Rule 140, §402. 

Subsequently, for reasons explained fully in the SNPR, the EPA reversed its prior 

proposed denial of the Petition with respect to the affirmative defense provision Maricopa 

County Air Pollution Control Regulation 3, Rule 140, §401 applicable to malfunctions. Also for 

reasons explained in the SNPR, the EPA reproposed granting of the Petition with respect to the 

affirmative defense provision in Maricopa County Air Pollution Control Regulation 3, Rule 140, 

§402 applicable to startup and shutdown, but it proposed to revise the basis for the finding of 

substantial inadequacy and the SIP call for this provision. 

Consequently, the EPA proposed to find that the provisions in Maricopa County Air 

Pollution Control Regulation 3, Rule 140, §401 and Maricopa County Air Pollution Control 
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Regulation 3, Rule 140, §402 are substantially inadequate to meet CAA requirements and thus 

proposed to issue a SIP call with respect to these provisions. 

In this final action, the EPA is granting the Petition with respect to Maricopa County Air 

Pollution Control Regulation 3, Rule 140, §401 and Maricopa County Air Pollution Control 

Regulation 3, Rule 140, §402. Accordingly, the EPA is finding that these provisions are 

substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with 

respect to these provisions. This action is fully consistent with what the EPA proposed in 

February 2013 as revised in the SNPR. Please refer to the Response to Comment document 

available in the docket for this rulemaking concerning any comments specific to the Arizona SIP 

that the EPA received and considered during the development of this rulemaking. 

3. Arizona: Pima County 

As described in section IX.J.3 of the February 2013 proposal, the Petitioner objected to a 

provision in the Pima County Department of Environmental Quality’s (PCDEQ) Rule 706 that 

pertains to enforcement discretion. 

For reasons explained fully in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to PCDEQ Rule 706. 

In this final action, the EPA is denying the Petition with respect to PCDEQ Rule 706. 

This action is fully consistent with what the EPA proposed in February 2013. Please refer to the 

Response to Comment document available in the docket for this rulemaking concerning any 

comments specific to the Arizona SIP that the EPA received and considered during the 

development of this rulemaking. 

4. California: Eastern Kern Air Pollution Control District 
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The Petitioner did not identify any provisions in the SIP for the state of California, which 

is why this state was not explicitly addressed in the February 2013 proposal. 

Subsequently, for reasons explained fully in the SNPR, the EPA identified an affirmative 

defense provision in the SIP for the state of California applicable in the Eastern Kern Air 

Pollution Control District (APCD), and the EPA proposed to make a finding of substantial 

inadequacy and to issue a SIP call for this provision. The affirmative defense is included in Kern 

County “Rule 111 Equipment Breakdown.” This SIP provision provides an affirmative defense 

available to sources for excess emissions that occur during a breakdown condition (i.e., 

malfunction). 

In this final action, the EPA is finding that Kern County Rule 111 Equipment Breakdown 

in the California SIP applicable in the Eastern Kern APCD381 is substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. This 

action is fully consistent with what the EPA proposed in the SNPR. Please refer to the Response 

to Comment document available in the docket for this rulemaking concerning any comments 

specific to the California SIP that the EPA received and considered during the development of 

this rulemaking. 

5. California: Imperial County Air Pollution Control District 

The Petitioner did not identify any provisions in the SIP for the state of California, which 

is why this state was not explicitly addressed in the February 2013 proposal. 

 

381 The EPA is in this final action making a finding of substantial inadequacy and issuing a SIP 

call for Kern County Rule 111 Equipment Breakdown in the California SIP as it applies in each 

the Eastern Kern APCD and the San Joaquin Valley Unified APCD. 
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Subsequently, for reasons explained fully in the SNPR, the EPA identified an affirmative 

defense provision in the SIP for the state of California applicable in the Imperial Valley APCD, 

and the EPA proposed to make a finding of substantial inadequacy and to issue a SIP call for this 

provision. The affirmative defense is included in Imperial County “Rule 111 Equipment 

Breakdown.” This SIP provision provides an affirmative defense available to sources for excess 

emissions that occur during a breakdown condition (i.e., malfunction). 

In this final action, the EPA is finding that Imperial County “Rule 111 Equipment 

Breakdown” in the California SIP applicable in the Imperial Valley APCD is substantially 

inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with respect to this 

provision. This action is fully consistent with what the EPA proposed in the SNPR. Please refer 

to the Response to Comment document available in the docket for this rulemaking concerning 

any comments specific to the California SIP that the EPA received and considered during the 

development of this rulemaking. 

6. California: San Joaquin Valley Unified Air Pollution Control District 

The Petitioner did not identify any provisions in the SIP for the state of California, which 

is why this state was not explicitly addressed in the February 2013 proposal. 

Subsequently, for reasons explained fully in the SNPR, the EPA identified affirmative 

defense provisions in the SIP for the state of California applicable in the San Joaquin Valley 

Unified APCD, and the EPA proposed to make a finding of substantial inadequacy and to issue a 

SIP call for these provisions. The affirmative defenses are included in: (i) Fresno County “Rule 

110 Equipment Breakdown”; (ii) Kern County “Rule 111 Equipment Breakdown”; (iii) Kings 

County “Rule 111 Equipment Breakdown”; (iv) Madera County “Rule 113 Equipment 

Breakdown”; (v) Stanislaus County “Rule 110 Equipment Breakdown”; and (vi) Tulare County 
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“Rule 111 Equipment Breakdown.” Each of these SIP provisions provides an affirmative defense 

available to sources for excess emissions that occur during a breakdown condition (i.e., 

malfunction). 

In this final action, the EPA is finding that the following six provisions in the California 

SIP applicable in the San Joaquin Valley Unified APCD are substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to these provisions: (i) 

Fresno County “Rule 110 Equipment Breakdown”; (ii) Kern County “Rule 111 Equipment 

Breakdown”; (iii) Kings County “Rule 111 Equipment Breakdown”; (iv) Madera County “Rule 

113 Equipment Breakdown”; (v) Stanislaus County “Rule 110 Equipment Breakdown”; and (vi) 

Tulare County “Rule 111 Equipment Breakdown.”382 This action is fully consistent with what 

the EPA proposed in the SNPR. Please refer to the Response to Comment document available in 

the docket for this rulemaking concerning any comments specific to the California SIP that the 

EPA received and considered during the development of this rulemaking. 

K. Affected States in EPA Region X 

1. Alaska 

As described in section IX.K.1 of the February 2013 proposal, the Petitioner objected to a 

provision in the Alaska SIP that provides an excuse for “unavoidable” excess emissions that 

occur during SSM events, including startup, shutdown, scheduled maintenance and “upsets” 

(Alaska Admin. Code tit. 18 § 50.240). The provision provides: “Excess emissions determined to 

be unavoidable under this section will be excused and are not subject to penalty. This section 

 

382 The EPA is in this final action making a finding of substantial inadequacy and issuing a SIP 

call for Kern County Rule 111 Equipment Breakdown in the California SIP as it applies in each 

the Eastern Kern APCD and the San Joaquin Valley Unified APCD. 
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does not limit the department’s power to enjoin the emission or require corrective action.” As the 

Petitioner pointed out, the provision is worded as if it were an affirmative defense, but it uses 

criteria for enforcement discretion. 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Alaska Admin. Code tit. 18 § 50.240 on the basis that, to the extent the 

provision was intended to be an affirmative defense, it was not a permissible affirmative defense 

provision consistent with the requirements of the CAA as interpreted in the EPA’s 1999 SSM 

Guidance. 

Subsequently, for reasons explained in the SNPR, the EPA reproposed granting of the 

Petition with respect to Alaska Admin. Code tit. 18 § 50.240, but it proposed to revise the basis 

for the finding of substantial inadequacy and the SIP call for this provision. 

Consequently, the EPA proposed to find that Alaska Admin. Code tit. 18 § 50.240 is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to Alaska Admin. Code 

tit. 18 § 50.240. Accordingly, the EPA is finding that this provision is substantially inadequate to 

meet CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. 

This action is fully consistent with what the EPA proposed in February 2013 as revised in the 

SNPR. Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the Alaska SIP that the EPA received and 

considered during the development of this rulemaking. 

2. Idaho 
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As described in section IX.K.2 of the February 2013 proposal, the Petitioner objected to a 

provision in the Idaho SIP that appears to grant enforcement discretion to the state as to whether 

to impose penalties for excess emissions during certain SSM events (Idaho Admin. Code r. 

58.01.01.131). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to Idaho Admin. Code r. 58.01.01.131. 

In this final action, the EPA is denying the Petition with respect to Idaho Admin. Code r. 

58.01.01.131. This action is fully consistent with what the EPA proposed in February 2013. 

Please refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Idaho SIP that the EPA received and considered during 

the development of this rulemaking. 

3. Oregon 

As described in section IX.K.3 of the February 2013 proposal, the Petitioner objected to a 

provision in the Oregon SIP that grants enforcement discretion to the state to pursue violations 

for excess emissions during certain SSM events (Or. Admin. R. 340-028-1450). 

For reasons explained fully in the February 2013 proposal, the EPA proposed to deny the 

Petition with respect to Or. Admin. R. 340-028-1450. 

In this final action, the EPA is denying the Petition with respect to Or. Admin. R. 340-

028-1450. This action is fully consistent with what the EPA proposed in February 2013. Please 

refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Oregon SIP that the EPA received and considered 

during the development of this rulemaking. 

4. Washington 
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As described in section IX.K.4 of the February 2013 proposal, the Petitioner objected to a 

provision in the Washington SIP that provides an excuse for “unavoidable” excess emissions that 

occur during certain SSM events, including startup, shutdown, scheduled maintenance and 

“upsets” (Wash. Admin. Code § 173-400-107). The provision provides that “[e]xcess emissions 

determined to be unavoidable under the procedures and criteria under this section shall be 

excused and are not subject to penalty.” The Petitioner argued that this provision excuses excess 

emissions in violation of the CAA and the EPA’s SSM Policy, which require all such emissions 

to be treated as violations of the applicable SIP emission limitations. As the Petitioner pointed 

out, the provision is worded as if it were an affirmative defense, but it uses criteria for 

enforcement discretion. 

For reasons explained fully in the February 2013 proposal, the EPA proposed to grant the 

Petition with respect to Wash. Admin. Code § 173-400-107 on the basis that, to the extent the 

provision was intended to be an affirmative defense, it was not a permissible affirmative defense 

provision consistent with the requirements of the CAA as interpreted in the EPA’s 1999 SSM 

Guidance. 

Subsequently, for reasons explained in the SNPR, the EPA reproposed granting of the 

Petition with respect to Wash. Admin. Code § 173-400-107, but it proposed to revise the basis 

for the finding of substantial inadequacy and the SIP call for this provision. 

Consequently, the EPA proposed to find that Wash. Admin. Code § 173-400-107 is 

substantially inadequate to meet CAA requirements and thus proposed to issue a SIP call with 

respect to this provision. 

In this final action, the EPA is granting the Petition with respect to Wash. Admin. Code § 

173-400-107. Accordingly, the EPA is finding that this provision is substantially inadequate to 
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meet CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. 

This action is fully consistent with what the EPA proposed in February 2013 as revised in the 

SNPR. Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the Washington SIP that the EPA received and 

considered during the development of this rulemaking. 

5. Washington: Energy Facility Site Evaluation Council 

The Petitioner did not identify any provisions in the SIP for the state of Washington that 

specifically apply to the Energy Facility Site Evaluation Council (EFSEC) area, which is why 

this area was not explicitly addressed in the February 2013 proposal. 

Subsequently, for reasons explained fully in the SNPR, the EPA identified affirmative 

defense provisions in the SIP for the state of Washington that relate to the EFSEC, and the EPA 

proposed to make a finding of substantial inadequacy and to issue a SIP call for these provisions 

in Wash. Admin. Code § 463-39-005. In the EFSEC portion of the SIP, Wash. Admin. Code § 

463-39-005 adopts by reference Wash. Admin. Code § 173-400-107, thereby incorporating the 

affirmative defenses applicable to startup, shutdown, scheduled maintenance and “upsets” that 

the EPA is also finding substantially inadequate in Wash. Admin. Code § 173-400-107 (see 

section IX.K.4 of this notice). 

In this final action, the EPA is finding that Wash. Admin. Code § 463-39-005 is 

substantially inadequate to meet CAA requirements and the EPA is thus issuing a SIP call with 

respect to this provision. This action is fully consistent with what the EPA proposed in the 

SNPR. Please refer to the Response to Comment document available in the docket for this 

rulemaking concerning any comments specific to the Washington SIP that the EPA received and 

considered during the development of this rulemaking. 
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6. Washington: Southwest Clean Air Agency 

The Petitioner did not identify any provisions in the SIP for the state of Washington that 

specifically apply in the portion of the state regulated by the Southwest Clean Air Agency 

(SWCAA),383 which is why this area was not explicitly addressed in the February 2013 proposal. 

Subsequently, for reasons explained fully in the SNPR, the EPA identified affirmative 

defense provisions in the SIP for the state of Washington that apply in the portion of the state 

regulated by SWCAA, and the EPA proposed to make a finding of substantial inadequacy and to 

issue a SIP call for these provisions. The affirmative defenses are included in the SIP in 

SWAPCA “400-107 Excess Emissions.” This SIP section provides an affirmative defense 

available to sources for excess emissions that occur during startup and shutdown, maintenance 

and upsets (i.e., malfunctions). It is identical to Wash. Admin. Code § 173-400-107 in all 

respects except that SWAPCA 400-107(3) contains a more stringent requirement for the 

reporting of excess emissions. 

In this final action, the EPA is finding that SWAPCA “400-107 Excess Emissions” in the 

Washington SIP applicable in the area regulated by SWCAA is substantially inadequate to meet 

CAA requirements and the EPA is thus issuing a SIP call with respect to this provision. This 

action is fully consistent with what the EPA proposed in February 2013 as revised in the SNPR. 

Please refer to the Response to Comment document available in the docket for this rulemaking 

concerning any comments specific to the Washington SIP that the EPA received and considered 

during the development of this rulemaking. 

 

383 The EPA notes that the SWCAA was formerly named, and in some places in the SIP still 

appears, as the “Southwest Air Pollution Control Authority” or “SWAPCA.” The EPA 

anticipates that the name will be updated in the SIP in due course as the state revises the SIP. 
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X. Implementation Aspects of EPA’s SSM SIP Policy 

A. Recommendations Concerning Alternative Emission Limitations for Startup and 

Shutdown 

In response to a SIP call concerning an existing automatic or discretionary exemption for 

excess emissions during SSM events, the EPA anticipates that a state may elect to create an 

alternative emission limitation that applies during startup and shutdown events (or during any 

other normal mode of operation during which the exemption may have applied) as a revised 

element or component of the existing emission limitation. The EPA emphasizes that states have 

discretion to revise the identified deficient provisions by any means they choose, so long as the 

revised provision is consistent with CAA requirements for SIP provisions. If a state elects to 

create an alternative emission limitation to replace an existing exemption, there are several issues 

that the state should consider. 

First, as explained in sections VII.B and XI of this document, the EPA has longstanding 

guidance that provides recommendations to states concerning the development of alternative 

emission limitations applicable during startup and shutdown to replace exemptions in existing 

SIP provisions. The EPA first provided this guidance in the 1999 SSM Guidance but has 

reiterated and clarified its guidance in this action. The EPA recommends that states consider the 

seven clarified criteria described in sections VII.B and XI of this document when developing 

new alternative emission limitations to replace automatic or discretionary exemptions, in order to 

assure that the revised provisions submitted to the EPA for approval meet basic CAA 

requirements for SIP emission limitations. 

Second, the EPA reiterates that SIP emission limitations that are expressed as numerical 

limitations do not necessarily have to require the same numerical level of emissions during all 
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modes of normal source operation. Under appropriate circumstances consistent with the criteria 

that the EPA recommends for alternative emission limitations, it may be appropriate to have a 

numerical emission limitation that has a higher numerical level applicable during specific modes 

of source operation, such as during startup and shutdown. For example, if a rate-based NOx 

emission limitation in the SIP applies to a specific source category, then it may be appropriate 

for that emission limitation to have a higher numerical standard applicable during defined 

periods of startup or shutdown. Such an approach can be consistent with SIP requirements, so 

long as that higher numerical level for startup or shutdown is properly established and is legally 

and practically enforceable, and so long as other overarching CAA requirements are also met. 

However, alternative emission limitations applicable during startup and shutdown cannot be 

inappropriately high or an effectively unlimited or uncontrolled level of emissions, as those 

would constitute impermissible de facto exemptions for emissions during certain modes of 

operation. 

Third, the EPA reiterates that SIP emission limitations do not necessarily have to be 

expressed in terms of a numerical level of emissions. There are many sources for which a 

numerically expressed emission limitation will be the most appropriate and will result in the 

most legally and practically enforceable SIP requirements.384 However, the EPA recognizes that 

for some source categories, under some circumstances, it may be appropriate for the SIP 

emission limitation to include a specific technological control requirement or specific work 

 

384 The EPA notes that in the CAA there is a presumption in favor of numerical emission 

limitations for purposes of section 112 and section 169, but section 110(a) does not include such 

an explicit presumption. However, there may be sources for which a numerically expressed 

emission limitation is the one that is most legally and practically enforceable, even during startup 

and shutdown, and for which a numerically expressed emission limitation is thus most 

appropriate. 
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practice requirement that applies during specified modes of source operation such as startup and 

shutdown. For example, if the otherwise applicable numerical SO2 emission limitation in the SIP 

is not achievable, and the otherwise required SO2 control measure is not effective during startup 

and shutdown and/or measurement of emissions during startup and shutdown is not reasonably 

feasible, then it may be appropriate for that emission limitation to impose a different control 

measure, such as use of low sulfur coal, applicable during defined periods of startup and 

shutdown in lieu of a numerically expressed emission limitation. Such an approach can be 

consistent with SIP requirements, so long as that alternative control measure applicable during 

startup and shutdown is properly established and is legally and practically enforceable as a 

component of the emission limitation, and so long as other overarching CAA requirements are 

also met. 

Fourth, the EPA notes that revisions to replace existing automatic or discretionary 

exemptions for SSM events with alternative emission limitations applicable during startup and 

shutdown also need to meet the applicable overarching CAA requirements with respect to the 

SIP emission limitation at issue. For example, if the emission limitation is in the SIP to meet the 

requirement that the source category be subject to RACT level controls for NOx for purposes of 

the ozone NAAQS, then the state should assure that the higher numerical level or other control 

measure that will apply to NOx emissions during startup and shutdown does constitute a RACT 

level of control for such sources for such pollutant during such modes of operation. 

Finally, the EPA notes that states should not replace automatic or discretionary 

exemptions for excess emissions during SSM events with alternative emission limitations that 

are a generic requirement such as a “general duty to minimize emissions” provision or an 
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“exercise good engineering judgment” provision.385 While such provisions may serve an 

overarching purpose of encouraging sources to design, maintain and operate their sources 

correctly, such generic clauses are not a valid substitute for more specific emission limitations 

that apply during normal modes of operation such as startup and shutdown. 

B. Recommendations for Compliance With Section 110(l) and Section 193 for SIP Revisions 

In response to a SIP call for any type of deficient provision, the EPA anticipates that each 

state will determine the best way to revise its SIP provisions to bring them into compliance with 

CAA requirements. In this action the EPA is only identifying the provisions that need to be 

revised because they violate fundamental requirements of the CAA and providing guidance to 

states in the SSM Policy concerning the types of provisions that are and are not permissible with 

respect to the treatment of excess emissions during SSM events. The EPA recognizes that one 

important consideration for air agencies as they evaluate how best to revise their SIP provisions 

in response to this SIP call is the nature of the analysis that will be necessary for the resulting 

SIP revisions under section 110(l) and section 193. The EPA wants to provide general guidance 

on this important issue in order to assist states with SIP revisions in response to the SIP call. 

Section 110(k)(3) directs the EPA to approve SIP submissions that comply with 

applicable CAA requirements and to disapprove those that do not. Under section 110(l), the EPA 

is prohibited from approving any SIP revision that would interfere with any applicable 

requirement concerning attainment and reasonable further progress or any other requirements of 

the CAA. To illustrate different ways in which section 110(l) and section 193 may apply in the 

 

385 The EPA notes that the “general duty” imposed under CAA section 112(r) is a separate 

standard, in addition to the otherwise applicable emission limitations and is not in lieu of those 

requirements. 
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evaluation of future SIP submissions in response to the SIP call, the EPA anticipates that there 

are several common scenarios that states may wish to consider when revising their SIPs: 

Example 1: A state elects to revise an existing SIP provision by removing an existing 

automatic exemption provision, director’s discretion provision, enforcement discretion provision 

or affirmative defense provision, without altering any other aspects of the SIP provision at issue 

(e.g., elects to retain the emission limitation for the source category but eliminate the exemption 

for emissions during SSM events). Although the EPA must review each SIP submission for 

compliance with section 110(l) and section 193 on the facts and circumstances of the revision, 

the Agency believes in general that this type of SIP revision should not entail a complicated 

analysis to meet these statutory requirements. Presumably, removal of the impermissible 

components of preexisting SIP provisions would not constitute backsliding, would in fact 

strengthen the SIP and would be consistent with the overarching requirement that the SIP 

revision be consistent with the requirements of the CAA. Accordingly, the EPA believes that this 

type of SIP revision should not entail a complicated analysis for purposes of section 110(l). If the 

SIP revision is also governed by section 193, then elimination of the deficiency will likewise 

presumably result in equal or greater emission reductions and thus comply with section 193 

without the need for a more complicated analysis. The EPA has recently evaluated a SIP revision 

to remove specific SSM deficiencies in this manner.386 

Example 2: A state elects to revise its SIP provision by replacing an automatic exemption 

for excess emissions during startup and shutdown events with an appropriate alternative emission 

 

386 See “Approval and Promulgation of Implementation Plans; Kentucky; Approval of Revisions 

to the Jefferson County Portion of the Kentucky SIP; Emissions During Startups, Shutdowns, 

and Malfunctions,” proposed at 78 FR 29683 (May 21, 2013), finalized at 79 FR 33101 (June 10, 

2014). 
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limitation (e.g., a different numerical limitation or different other control requirement) that is 

explicitly applicable during startup and shutdown as a component of the revised emission 

limitation. Although the EPA must review each SIP revision for compliance with section 110(l) 

and section 193 on the facts and circumstances of the revision, the Agency believes in general 

that this type of SIP revision should not entail a complicated analysis to meet these statutory 

requirements. Presumably, the replacement of an automatic exemption applicable to startup and 

shutdown with an appropriate alternative emission limitation would not constitute backsliding, 

would strengthen the SIP and would be consistent with the overarching requirement that the SIP 

revision be consistent with the requirements of the CAA. The state should develop that 

alternative emission limitation in accordance with the EPA’s guidance recommendations for 

such provisions to assure that it would meet CAA requirements.387 In addition, that alternative 

emission limitation would both need to meet the overarching CAA applicable requirements that 

the emission limitation is designed and intended to meet (e.g., RACT-level controls for the 

source category in an attainment area for a NAAQS) and need to be legally and practically 

enforceable (e.g., have adequate recordkeeping, reporting, monitoring or other features requisite 

for enforcement). If a state has developed the alternative emission limitation consistent with 

these criteria, then the EPA anticipates that the revision of the emission limitation to replace the 

exemption with an alternative emission limitation applicable to startup and shutdown would not 

be backsliding, would be a strengthening of the SIP and would be consistent with the 

requirement of section 110(l) that a SIP revision be consistent with the requirements of the CAA. 

Similarly, if section 193 applies to the emission limitation that the state is revising, then the 

 

387 These recommendations are discussed in detail in section VII.B.2 of this document. 
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replacement of an exemption applicable to emissions during startup and shutdown with an 

appropriately developed alternative emission limitation that explicitly applies during startup and 

shutdown would presumably result in equal or greater emission reductions and thus should meet 

the requirements of section 193 without the need for a more complicated analysis. 

Example 3: A state elects to revise an existing SIP provision not merely by removal of an 

existing automatic exemption provision, director’s discretion provision, enforcement discretion 

provision or affirmative defense provision, but by the removal of the deficiency combined with a 

total revision of the emission limitation. The EPA anticipates that there may be emission 

limitations for which a state may elect to do such a wholesale revision of the SIP provision as 

part of eliminating an impermissible component of the existing provision (e.g., removal of an 

automatic exemption applicable to emissions during SSM events through a complete revision of 

the emission limitation to create a different emission limitation that applies at all times, including 

during SSM events). In developing a completely revised SIP provision, the state should assure 

that the replacement provision meets the applicable overarching CAA requirements that the 

provision is designed and intended to meet, is legally and practically enforceable and is not less 

stringent than the prior SIP provision. The EPA believes in general that this type of SIP revision 

may require a more in-depth analysis to meet these statutory requirements of section 110(l) and 

section 193. To the extent that there is any concern that the revised SIP provision is less stringent 

than the provision it replaces, then there will need to be a careful evaluation as to whether the 

revised provision would interfere with any applicable requirement concerning attainment and 

reasonable further progress and with any other applicable requirement of the CAA. Presumably, 

however, so long as the state has properly developed the revised emission limitation to assure 

that it meets the overarching CAA requirements and to assure that it will not result in a less 
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stringent emission limitation, then the complete revision of the emission limitation would not 

constitute backsliding, would be a strengthening of the SIP and thereby would comply with 

section 110(l). If the SIP revision is also governed by section 193, then there will also need to be 

an analysis to assure that the revision will result in equal or greater emission reductions and thus 

comply with section 193. To the extent that there is concern that the revision would result in a 

less stringent emission limitation than the preexisting emission limitation, then a more complex 

analysis would likely be required. 

The EPA emphasizes that each SIP revision must be evaluated for compliance with 

section 110(l) and section 193 on the facts and circumstances of the specific revision, but these 

examples are intended to provide general guidance on the considerations and the nature of the 

analysis that may be appropriate for different types of SIP revisions. States should contact their 

respective EPA Regional Offices for further recommendations and assistance concerning the 

analysis appropriate for specific SIP revisions in response to this SIP call. 

XI. Statement of the EPA’s SSM SIP Policy as of 2015 

The EPA’s longstanding interpretation of the CAA is that SIP provisions cannot include 

exemptions from emission limitations for emissions during SSM events. In order to be 

permissible in a SIP, an emission limitation must be applicable to the source continuously, i.e., 

cannot include periods during which emissions from the source are legally or functionally 

exempt from regulation. Regardless of its form, a fully approvable SIP emission limitation must 

also meet all substantive requirements of the CAA applicable to such a SIP provision, e.g., the 

statutory requirement of section 172(c)(1) for imposition of RACM and RACT on sources 

located in designated nonattainment areas. 
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This section of the notice provides more specific guidance on the appropriate treatment of 

emissions during SSM events in SIP provisions, replacing the EPA’s prior guidance issued in 

memoranda of 1982, 1983, 1999 and 2001. The more extended explanations and interpretations 

provided in other sections of this notice are also applicable, should a situation arise that is not 

sufficiently covered by this section’s more concise policy statement. This SSM Policy as of 2015 

is a policy statement and thus constitutes guidance. As guidance, this SSM Policy as of 2015 

does not bind states, the EPA or other parties, but it does reflect the EPA’s interpretation of the 

statutory requirements of the CAA. The EPA’s evaluation of any SIP provision, whether 

prospectively in the case of a new provision in a SIP submission or retrospectively in the case of 

a previously approved SIP submission, must be conducted through a notice-and-comment 

rulemaking in which the EPA will determine whether or not a given SIP provision is consistent 

with the requirements of the CAA and applicable regulations. 

A. Definitions 

The term alternative emission limitation means, in this notice, an emission limitation in a 

SIP that applies to a source during some but not all periods of normal operation (e.g., applies 

only during a specifically defined mode of operation such as startup or shutdown). An alternative 

emission limitation is a component of a continuously applicable SIP emission limitation, and it 

may take the form of a control measure such as a design, equipment, work practice or operational 

standard (whether or not numerical). This definition of the term is independent of the statutory 

definitions in sections 111(h)(3) and 112(h)(3). The latter definitions pertain to the conditions 

under which the EPA may pursuant to sections 111 and 112 promulgate emission limitations, or 

components of emission limitations, that are not necessarily in numeric format. 
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The term automatic exemption means a generally applicable provision in a SIP that 

would provide that if certain conditions existed during a period of excess emissions, then those 

exceedances would not be considered violations of the applicable emission limitations. 

The term director’s discretion provision means, in general, a regulatory provision that 

authorizes a state regulatory official unilaterally to grant exemptions or variances from otherwise 

applicable emission limitations or control measures, or to excuse noncompliance with otherwise 

applicable emission limitations or control measures, which would be binding on the EPA and the 

public. 

The term emission limitation means, in the context of a SIP, a legally binding restriction 

on emissions from a source or source category, such as a numerical emission limitation, a 

numerical emission limitation with higher or lower levels applicable during specific modes of 

source operation, a specific technological control measure requirement, a work practice standard, 

or a combination of these things as components of a comprehensive and continuous emission 

limitation in a SIP provision. In this respect, the term emission limitation is defined as in section 

302(k) of the CAA. By definition, an emission limitation can take various forms or a 

combination of forms, but in order to be permissible in a SIP it must be applicable to the source 

continuously, i.e., cannot include periods during which emissions from the source are legally or 

functionally exempt from regulation. Regardless of its form, a fully approvable SIP emission 

limitation must also meet all substantive requirements of the CAA applicable to such a SIP 

provision, e.g., the statutory requirement of section 172(c)(1) for imposition of reasonably 

available control measures and reasonably available control technology (RACM and RACT) on 

sources located in designated nonattainment areas. 
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The term excess emissions means the emissions of air pollutants from a source that 

exceed any applicable SIP emission limitation. In particular, this term includes those emissions 

above the otherwise applicable SIP emission limitation that occur during startup, shutdown, 

malfunction or other modes of source operation, i.e., emissions that would be considered 

violations of the applicable emission limitation but for an impermissible automatic or 

discretionary exemption from such emission limitation. 

The term malfunction means a sudden and unavoidable breakdown of process or control 

equipment. 

The term shutdown means, generally, the cessation of operation of a source for any 

reason. In this notice, the EPA uses this term in the generic sense. In individual SIP provisions it 

may be appropriate to include a specifically tailored definition of this term to address a particular 

source category for a particular purpose. 

The term SSM refers to startup, shutdown or malfunction at a source. It does not include 

periods of maintenance at such a source. An SSM event is a period of startup, shutdown or 

malfunction during which there are exceedances of the applicable emission limitations and thus 

excess emissions. 

The term startup means, generally, the setting in operation of a source for any reason. In 

this notice, the EPA uses this term in the generic sense. In an individual SIP provision it may be 

appropriate to include a specifically tailored definition of this term to address a particular source 

category for a particular purpose. 

The term malfunction means a sudden and unavoidable breakdown of process or control 

equipment. 
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The term shutdown means, generally, the cessation of operation of a source for any 

reason. In this notice, the EPA uses this term in the generic sense. In individual SIP provisions it 

may be appropriate to include a specifically tailored definition of this term to address a particular 

source category for a particular purpose. 

The term SSM refers to startup, shutdown or malfunction at a source. It does not include 

periods of maintenance at such a source. An SSM event is a period of startup, shutdown or 

malfunction during which there are exceedances of the applicable emission limitations and thus 

excess emissions. 

The term startup means, generally, the setting in operation of a source for any reason. In 

this notice, the EPA uses this term in the generic sense. In an individual SIP provision it may be 

appropriate to include a specifically tailored definition of this term to address a particular source 

category for a particular purpose. 

B. Emission limitations in SIPs must apply continuously during all modes of operation, 

without automatic or discretionary exemptions or overly broad enforcement discretion 

provisions that would bar enforcement by the EPA or by other parties in federal court through a 

citizen suit. 

In accordance with CAA section 302(k), SIPs must contain emission limitations that 

“limit the quantity, rate, or concentration of emissions of air pollutants on a continuous basis.” 

All of the specific requirements of a SIP emission limitation must be discernible in the SIP, for 

clarity preferably within a single section or provision; must meet the applicable substantive and 

stringency requirements of the CAA; and must be legally and practically enforceable. 

To the extent that a SIP provision allows any period of time when a source is not subject 

to any requirement that limits emissions, the requirements limiting the source’s emissions by 
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definition cannot do so “on a continuous basis.” Such a source would not be subject to an 

“emission limitation,” as required by the definition of that term under section 302(k). However, 

the CAA allows SIP provisions that include numerical limitations, specific technological control 

requirements and/or work practice requirements that limit emissions during startup and shutdown 

as components of a continuously applicable emission limitation, as discussed in section XI.C of 

this document. 

Accordingly, automatic or discretionary exemption provisions applicable during SSM 

events are impermissible in SIPs. This impermissibility applies even for “brief” exemptions from 

limits on emissions, because such exemptions nevertheless render the limitation noncontinuous. 

Furthermore, the fact that a SIP provision includes prerequisites to qualifying for an SSM 

exemption does not mean those prerequisites are themselves an “alternative emission limitation” 

applicable during SSM events. 

Automatic exemptions. A typical SIP provision that includes an impermissible automatic 

exemption would provide that a source has to meet a specific emission limitation during all 

modes of operation except startup, shutdown and malfunction; by definition any excess 

emissions during such events would not be violations and thus there could be no enforcement 

based on those excess emissions. With respect to automatic exemptions from emission 

limitations in SIPs, the EPA’s longstanding interpretation of the CAA is that such exemptions 

are impermissible because they are inconsistent with the fundamental requirements of the CAA. 

Automatic exemptions from otherwise applicable emission limitations render those emission 

limitations less than continuous as required by CAA sections 302(k), 110(a)(2)(A) and 

110(a)(2)(C), thereby inconsistent with a fundamental requirement of the CAA and thus 

substantially inadequate as contemplated in CAA section 110(k)(5). 
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Discretionary exemptions. A typical SIP provision that includes an impermissible 

“director’s discretion” component would purport to authorize air agency personnel to modify 

existing SIP requirements under certain conditions, e.g., to grant a variance from an otherwise 

applicable emission limitation if the source could not meet the requirement in certain 

circumstances.388 Director’s discretion provisions operate to allow air agency personnel to make 

unilateral decisions on an ad hoc basis, up to and including the granting of complete exemptions 

for emissions during SSM events, thereby negating any possibility of enforcement for what 

would be violations of the otherwise applicable emission limitation. With respect to such 

director’s discretion provisions in SIPs, the EPA interprets the CAA to prohibit these if they 

provide unbounded discretion to allow what would amount to a case-specific revision of the SIP 

without meeting the statutory requirements of the CAA for SIP revisions. In particular, the EPA 

interprets the CAA to preclude SIP provisions that provide director’s discretion authority to 

create discretionary exemptions for violations when the CAA would not allow such exemptions 

in the first instance. 

If an air agency elects to have SIP provisions that contain a director’s discretion feature, 

then to be consistent with CAA requirements the provisions must be structured so that any 

resulting variances or other deviations from the emission limitation or other SIP requirements 

have no federal law validity, unless and until the EPA specifically approves that exercise of the 

director’s discretion as a SIP revision. Barring such a later ratification by the EPA through a SIP 

 

388 The EPA notes that problematic “director’s discretion” provisions are not limited only to 

those that purport to authorize alternative emission limitations from those required in a SIP. 

Other problematic director’s discretion provisions include those that purport to provide for 

discretionary changes to other substantive requirements of the SIP, such as applicability, 

operating requirements, recordkeeping requirements, monitoring requirements, test methods or 

alternative compliance methods. 
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revision, the exercise of director’s discretion is only valid for state (or tribal) law purposes and 

would have no bearing in the event of an action to enforce the provision of the SIP as it was 

originally approved by the EPA. 

Adoption of the EPA’s NSPS or NESHAP that have not yet been revised. The EPA has 

recently begun revising and will continue to revise NSPS and NESHAP as needed, to make the 

EPA’s regulations consistent with CAA requirements by removing exemptions and affirmative 

defense provisions applicable to SSM events, and generally on the same legal basis as for this 

action. A state should not submit an NSPS or NESHAP for inclusion into its SIP as an emission 

limitation (whether through incorporation by reference or otherwise) unless either: (i) that NSPS 

or NESHAP does not include an exemption or affirmative defense for SSM events; or (ii) the 

state takes action as part of the SIP submission to render such exemption or affirmative defense 

inapplicable to the SIP emission limitation. Because SIP provisions must apply continuously, 

including during SSM events, the EPA can no longer approve SIP submissions that include any 

emission limitations with such exemptions, even if those emission limitations are NSPS or 

NESHAP regulations that the EPA has not yet revised to make consistent with CAA 

requirements. Alternatively, states may elect to adopt an existing NSPS or NESHAP as a SIP 

provision, so long as the SIP provision excludes the exemption or affirmative defense applicable 

to SSM events.389 States may also wish to replace the SSM exemption in NSPS or NESHAP 

regulations with appropriately developed alternative emission limitations that apply during 

 

389 Under CAA section 116, states have the explicit general authority to regulate more stringently 

than the EPA. Indeed, under section 116 states can regulate sources subject to EPA regulations 

promulgated under section 111 or section 112 so long as they do not regulate them less 

stringently. According, the EPA believes that states may elect to adopt EPA regulations under 

section 111 or section 112 as SIP provisions and expressly eliminate the exemptions for 

emissions during SSM events. 
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startup and shutdown in lieu of the SSM exemption. Otherwise, the EPA’s approval of the 

deficient SSM exemption provisions into the SIP would contravene CAA requirements for SIP 

provisions and would potentially result in misinterpretation or misapplication of the standards by 

regulators, regulated entities, courts and members of the public. The EPA emphasizes that the 

inclusion of an NSPS or NESHAP as an emission limitation in a state’s SIP is different and 

distinct from reliance on such standards indirectly, such as reliance on the NSPS or NESHAP as 

a source of emission reductions that may be taken into account for SIP planning purposes in 

emissions inventories or attainment demonstrations. For those uses, states may continue to rely 

on the EPA’s NSPS and NESHAP regulations, even those that have not yet been revised to 

remove inappropriate exemptions, in accordance with the requirements applicable to those SIP 

planning functions. 

Other modes of normal operation. SIPs also may not create automatic or discretionary 

exemptions from otherwise applicable emission limitations during periods such as 

“maintenance,” “load change,” “soot-blowing,” “on-line operating changes” or other similar 

normal modes of operation. Like startup and shutdown, the EPA considers all of these to be 

modes of normal operation at a source, for which the source can be designed, operated and 

maintained in order to meet an applicable emission limitations and during which the source 

should be expected to control and minimize emissions. Excess emissions that occur during 

planned and predicted periods should be treated as violations of applicable emission limitations. 

Accordingly, exemptions for emissions during these periods of normal source operation are not 

consistent with CAA requirements. 

It may be appropriate for an air agency to establish an alternative numerical limitation or 

other form of control measure that applies during these modes of source operation, as for startup 
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and shutdown events, but any such alternative emission limitation should be developed using the 

same criteria that the EPA recommends for alternative emission limitations applicable during 

startup and shutdown. Similarly, any SIP provision that includes an emission limitation for 

sources that includes alternative emission limitations applicable to modes of operation such as 

“maintenance,” “load change,” “soot-blowing” or “on-line operating changes” must also meet 

the applicable level of stringency for that type of emission limitation and be practically and 

legally enforceable. 

C. Emission limitations in SIPs may contain components applicable to different modes of 

operation that take different forms, and numerical emission limitations may have differing levels 

and forms for different modes of operation. 

There are approaches other than exemptions that would be consistent with CAA 

requirements for SIP provisions that states can use to address excess emissions during certain 

events. While automatic exemptions and director’s discretion exemptions from otherwise 

applicable emission limitations for SSM events are not consistent with the CAA, SIPs may 

include criteria and procedures for the use of enforcement discretion by air agency personnel, as 

described in section XI.E of this document. Similarly, SIPs may, rather than exempt excess 

emissions, include emission limitations that subject those emissions to alternative numerical 

limitations or other control requirements during startup and shutdown events or other normal 

modes of operation, so long as those components of the emission limitations meet applicable 

CAA requirements and are legally and practically enforceable. 

The EPA does not interpret section 110(a)(2) or section 302(k) to require that an emission 

limitation in a SIP provision be composed of a single, uniformly applicable numerical emission 

limitation. The text of section 110(a)(2) and section 302(k) does not require states to impose 
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emission limitations that include a static, inflexible standard. The critical aspect for purposes of 

section 302(k) is that the SIP provision impose limits on emissions on a continuous basis, 

regardless of whether the emission limitation as a whole is expressed numerically or as a 

combination of numerical limitations, specific control technology requirements and/or work 

practice requirements applicable during specific modes of operation, and regardless of whether 

the emission limitation is static or variable. Thus, emission limitations in SIP provisions do not 

have to be composed solely of numerical emission limitations applicable at all times. For 

example, so long as the SIP provision meets other applicable requirements, it may impose 

different numerical limitations for startup and shutdown. Also, for example, SIPs can contain 

numerical emission limitations applicable only to some periods and other forms of controls 

applicable only to some periods, with certain periods perhaps subject to both types of limitation. 

Thus, SIP emission limitations: (i) do not need to be numerical in format; (ii) do not have to 

apply the same limitation (e.g., numerical level) at all times; and (iii) may be composed of a 

combination of numerical limitations, specific technological control requirements and/or work 

practice requirements, with each component of the emission limitation applicable during a 

defined mode of source operation. In practice, it may be that numerical emission limitations are 

the most appropriate from a regulatory perspective (e.g., to be legally and practically 

enforceable) and thus the emission limitation would need to be established in this form to meet 

CAA requirements. It is important to emphasize, however, that regardless of how the state 

structures or expresses a SIP emission limitation—whether solely as one numerical limitation, as 

a combination of different numerical limitations or as a combination of numerical limitations, 

specific technological control requirements and/or work practice requirements that apply during 

certain modes of operation such as startup and shutdown—the emission limitation as a whole 
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must be continuous, must meet applicable CAA stringency requirements and must be legally and 

practically enforceable.390 

Startup and shutdown are part of the normal operation of a source and should be 

accounted for in the design and operation of the source. 391 It should be possible to determine an 

appropriate form and degree of emission control during startup and shutdown and to achieve that 

control on a regular basis. Thus, sources should be required to meet defined SIP emission 

limitations during startup and shutdown. However, the EPA interprets the CAA to permit SIP 

emission limitations that include alternative emission limitations specifically applicable during 

startup and shutdown. Regarding startup and shutdown periods, the EPA considers the following 

to be the correct approach to creating an emission limitation: (i) the emission limitation contains 

no exemption for emissions during SSM events; (ii) the component of any alternative emission 

limitation that applies during startup and shutdown is clearly stated and obviously is an emission 

limitation that applies to the source; (iii) the component of any alternative emission limitation 

that applies during startup and shutdown meets the applicable stringency level for this type of 

emission limitation; and (iv) the emission limitation contains requirements to make it legally and 

 

390 The EPA notes that CAA section 123 explicitly prohibits certain intermittent or supplemental 

controls on sources. In a situation where an emission limitation is continuous, by virtue of the 

fact that it has components applicable during all modes of source operation, the EPA would not 

interpret the components that applied only during certain modes of operation, e.g., startup and 

shutdown, to be prohibited intermittent or supplemental controls. 

391 Every source is designed, maintained and operated with the expectation that the source will at 

least occasionally start up and shut down, and thus these modes of operation are “normal” in the 

sense that they are to be expected. The EPA uses this term in the ordinary sense of the word to 

distinguish between such predictable modes of source operation and genuine “malfunctions,” 

which are by definition supposed to be unpredictable and unforeseen events that could not have 

been precluded by proper source design, maintenance and operation. 
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practically enforceable. Section XI.D of this document contains more specific recommendations 

to states for developing alternative emission limitations. 

In contrast to startup and shutdown, a malfunction is unpredictable as to the timing of the 

start of the malfunction event, its duration and its exact nature. The effect of a malfunction on 

emissions is therefore unpredictable and variable, making the development of an alternative 

emission limitation for malfunctions problematic. There may be rare instances in which certain 

types of malfunctions at certain types of sources are foreseeable and foreseen and thus are an 

expected mode of source operation. In such circumstances, the EPA believes that sources should 

be expected to meet the otherwise applicable emission limitation in order to encourage sources to 

be properly designed, maintained and operated in order to prevent or minimize any such 

malfunctions. To the extent that a given type of malfunction is so foreseeable and foreseen that a 

state considers it a normal mode of operation that is appropriate for a specifically designed 

alternative emission limitation, then such alternative should be developed in accordance with the 

recommended criteria for alternative emission limitations. The EPA does not believe that generic 

general-duty provisions, such as a general duty to minimize emissions, is sufficient as an 

alternative emission limitation for any type of event including malfunctions. 

States developing SIP revisions to remove impermissible exemption provisions from 

emissions limitations may choose to consider reassessing particular emission limitations, for 

example to determine whether limits originally applicable only during non-SSM periods can be 

revised such that well-managed emissions during planned operations such as startup and 

shutdown would not exceed the revised emission limitation, while still protecting air quality and 

meeting other applicable CAA requirements. Such a revision of an emission limitation will need 

to be submitted as a SIP revision for EPA approval if the existing limitation to be changed is 
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already included in the SIP or if the existing SIP relies on the particular existing emission 

limitation to meet a CAA requirement. 

Some SIPs contain other generic regulatory requirements frequently referred to as 

“general duty” type requirements, such as a general duty to minimize emissions at all times, a 

general duty to use good engineering judgment at all times or a general duty not to cause a 

violation of the NAAQS at any time. To the extent that such other general-duty requirement is 

properly established and legally and practically enforceable, the EPA would agree that it may be 

an appropriate separate requirement to impose upon sources in addition to the (continuous) 

emission limitation. The EPA itself imposes separate general duties of this type in appropriate 

circumstances. The existence of these generic provisions does not, however, legitimize 

exemptions for emissions during SSM events in a SIP provision that imposes an emission 

limitation. 

General-duty requirements that are not clearly part of or explicitly cross-referenced in a 

SIP emission limitation cannot be viewed as a component of a continuous emission limitation. 

Even if clearly part of or explicitly cross-referenced in the SIP emission limitation, however, a 

given general-duty requirement may not be consistent with the applicable stringency 

requirements for SIP provisions that should apply during startup and shutdown. In general, the 

EPA believes that a legally and practically enforceable alternative emission limitation applicable 

during startup and shutdown should be expressed as a numerical limitation, a specific 

technological control requirement or a specific work practice applicable to affected sources 

during specifically defined periods or modes of operation. Accordingly, while states are free to 

include general-duty provisions in their SIPs as separate additional requirements, for example, to 

ensure that owners and operators act consistent with reasonable standards of care, the EPA does 
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not recommend using these background standards to bridge unlawful interruptions in an emission 

limitation.392 

D. Recommendations for Development of Alternative Emission Limitations Applicable 

During Startup and Shutdown 

A state can develop special, alternative emission limitations that apply during startup or 

shutdown if the source cannot meet the otherwise applicable emission limitation in the SIP. SIP 

provisions may include alternative emission limitations for startup and shutdown as part of a 

continuously applicable emission limitation when properly developed and otherwise consistent 

with CAA requirements. However, if a non-numerical requirement does not itself (or in 

combination with other components of the emission limitation) limit the quantity, rate or 

concentration of air pollutants on a continuous basis, then the non-numerical standard (or 

overarching requirement) does not meet the statutory definition of an emission limitation under 

section 302(k). 

In cases in which measurement of emissions during startup and/or shutdown is not 

reasonably feasible, it may be appropriate for an emission limitation to include as a component a 

control for startup and/or shutdown periods other than a numerically expressed emission 

limitation. 

The federal NESHAP and NSPS regulations and the technical materials in the public 

record for those rules may provide assistance for states as they develop and consider emission 

 

392 For example, the EPA has concerns the some general-duty provisions, if at any point relied 

upon as the sole requirement purportedly limiting emissions, could undermine the ability to 

ensure compliance with SIP emission limitations relied on to achieve the NAAQS and other 

relevant CAA requirements at all times. See section 110(a)(2)(A), (C); US Magnesium, LLC v. 

EPA, 690 F.3d 1157, 1161–62 (10th Cir. 2012). 
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limitations and alternative emission limitations for sources in their states, and definitions of 

startup and shutdown events and work practices for them found in these regulations may be 

appropriate for adoption by the state in certain circumstances. In particular, the NSPS regulations 

should provide very relevant information for sources of the same type, size and control 

equipment type, even if the sources were not constructed or modified within a date range that 

would make them subject to the NSPS. The EPA therefore encourages states to explore these 

approaches. 

The EPA recommends that, in order to be approvable (i.e., meet CAA requirements), 

alternative requirements applicable to the source during startup and shutdown should be 

narrowly tailored and take into account considerations such as the technological limitations of 

the specific source category and the control technology that is feasible during startup and 

shutdown. The EPA recommends the following seven specific criteria as appropriate 

considerations for developing emission limitations in SIP provisions that apply during startup 

and shutdown: 

(1) The revision is limited to specific, narrowly defined source categories using specific 

control strategies (e.g., cogeneration facilities burning natural gas and using selective catalytic 

reduction); 

(2) Use of the control strategy for this source category is technically infeasible during 

startup or shutdown periods; 

(3) The alternative emission limitation requires that the frequency and duration of 

operation in startup or shutdown mode are minimized to the greatest extent practicable; 
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(4) As part of its justification of the SIP revision, the state analyzes the potential worstcase emissions that could occur during startup and shutdown based on the applicable alternative 

emission limitation; 

(5) The alternative emission limitation requires that all possible steps are taken to 

minimize the impact of emissions during startup and shutdown on ambient air quality; 

(6) The alternative emission limitation requires that, at all times, the facility is operated in 

a manner consistent with good practice for minimizing emissions and the source uses best efforts 

regarding planning, design, and operating procedures; and 

(7) The alternative emission limitation requires that the owner or operator’s actions 

during startup and shutdown periods are documented by properly signed, contemporaneous 

operating logs or other relevant evidence. 

If a state elects to create an emission limitation with different levels of control applicable 

during specifically defined periods of startup and shutdown than during other normal modes of 

operation, then the resulting emission limitation must meet the substantive requirements 

applicable to the type of SIP provision at issue, meet the applicable level of stringency for that 

type of emission limitation and be legally and practically enforceable. Alternative emission 

limitations applicable during startup and shutdown cannot be inappropriately high or an 

effectively unlimited or uncontrolled level of emissions, as those would constitute impermissible 

de facto exemptions for emissions during certain modes of operation. 

E. Enforcement Discretion Provisions 

One approach other than exemptions that would be consistent with CAA requirements for 

SIP provisions that states can use to address excess emissions during SSM events is to include in 

the SIP criteria and procedures for the use of enforcement discretion by air agency personnel. 
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SIPs may contain such provisions concerning the exercise of discretion by the air agency’s own 

personnel, but such provisions cannot bar enforcement by the EPA or by other parties through a 

citizen suit. 

Pursuant to the CAA, all parties with authority to bring an enforcement action to enforce 

SIP provisions (i.e., the state, the EPA or any parties who qualify under the citizen suit provision 

of section 304) have enforcement discretion that they may exercise as they deem appropriate in 

any given circumstances. For example, if the event that causes excess emissions is an actual 

malfunction that occurred despite reasonable care by the source operator to avoid malfunctions, 

then each of these parties may decide that no enforcement action is warranted. In the event that 

any party decides that an enforcement action is warranted, then it has enforcement discretion 

with respect to what remedies to seek from the court for the violation (e.g., injunctive relief, 

compliance order, monetary penalties or all of the above), as well as the type of injunctive relief 

and/or amount of monetary penalties sought.393 

As part of state programs governing enforcement, states can include regulatory provisions 

or may adopt policies setting forth criteria for how they plan to exercise their own enforcement 

authority. Under section 110(a)(2), states must have adequate authority to enforce provisions 

adopted into the SIP, but states can establish criteria for how they plan to exercise that authority. 

Such enforcement discretion provisions cannot, however, impinge upon the enforcement 

authority of the EPA or of others pursuant to the citizen suit provision of the CAA. Such 

enforcement discretion provisions in a SIP would be inconsistent with the enforcement structure 

 

393 The EPA notes that only the state and the Agency have authority to seek criminal penalties 

for knowing and intentional violation of CAA requirements. The EPA has this explicit authority 

under CAA section 113(c). 
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provided in the CAA. Specifically, the statute provides explicit independent enforcement 

authority to the EPA under CAA section 113 and to citizens under CAA section 304. Thus, the 

CAA contemplates that the EPA and citizens have authority to pursue enforcement for a 

violation even if the state elects not to do so. The EPA and citizens, and any federal court in 

which they seek to pursue an enforcement claim for violation of SIP requirements, must retain 

the authority to evaluate independently whether a source’s violation of an emission limitation 

warrants enforcement action. Potential for enforcement by the EPA or through a citizen suit 

provides an important safeguard in the event that the state lacks resources or ability to enforce 

violations and provides additional deterrence. Accordingly, a SIP provision that operates at the 

state’s election to eliminate the authority of the EPA or the public to pursue enforcement actions 

in federal court would undermine the enforcement structure of the CAA and would thus be 

substantially inadequate to meet fundamental requirements of the CAA. 

Also, states should not adopt overly broad enforcement discretion provisions for 

inclusion in their SIPs, even for their own personnel. Section 110(a)(2) requires states to have 

adequate enforcement authority, and overly broad enforcement discretion provisions would run 

afoul of this requirement if they have the effect of precluding adequate state authority to enforce 

SIP requirements. If such provisions are sufficiently specific, provide for sufficient public 

process and are sufficiently bounded, so that it is possible to anticipate at the time of the EPA’s 

approval of the SIP provision how that provision will actually be applied and the potential 

adverse impacts thereof, then such a provision might meet basic CAA requirements. In essence, 

if it is possible to anticipate and evaluate in advance how the exercise of enforcement discretion 

could affect compliance with other CAA requirements, then it may be possible to determine in 
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advance that the preauthorized exercise of director’s discretion will not interfere with other CAA 

requirements, such as providing for attainment and maintenance of the NAAQS. 

When using enforcement discretion in determining whether an enforcement action is 

appropriate in the case of excess emissions during a malfunction, satisfaction of the following 

criteria should be considered: 

(1) To the maximum extent practicable the air pollution control equipment, process 

equipment or processes were maintained and operated in a manner consistent with good practice 

for minimizing emissions; 

(2) Repairs were made in an expeditious fashion when the operator knew or should have 

known that applicable emission limitations were being exceeded. Off-shift labor and overtime 

were utilized, to the extent practicable, to ensure that such repairs were made as expeditiously as 

practicable; 

(3) The amount and duration of the excess emissions (including any bypass) were 

minimized to the maximum extent practicable during periods of such emissions; 

(4) All possible steps were taken to minimize the impact of the excess emissions on 

ambient air quality; and 

(5) The excess emissions are not part of a recurring pattern indicative of inadequate 

design, operation or maintenance. 

F. Affirmative Defense Provisions in SIPs 

The EPA believes that SIP provisions that function to alter the jurisdiction or discretion 

of the federal courts under CAA section 113 and section 304 to determine liability and to impose 

remedies are inconsistent with fundamental legal requirements of the CAA, especially with 

respect to the enforcement regime explicitly created by statute. Affirmative defense provisions 
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by their nature purport to limit or eliminate the authority of federal courts to find liability or to 

impose remedies through factual considerations that differ from, or are contrary to, the explicit 

grants of authority in section 113(b) and section 113(e). These provisions are not appropriate 

under the CAA, no matter what type of event they apply to, what criteria they contain or what 

forms of remedy they purport to limit or eliminate. 

Section 113(b) provides courts with explicit jurisdiction to determine liability and to 

impose remedies of various kinds, including injunctive relief, compliance orders and monetary 

penalties, in judicial enforcement proceedings. This grant of jurisdiction comes directly from 

Congress, and the EPA is not authorized to alter or eliminate this jurisdiction under the CAA or 

any other law. With respect to monetary penalties, CAA section 113(e) explicitly includes the 

factors that federal courts and the EPA are required to consider in the event of judicial or 

administrative enforcement for violations of CAA requirements, including SIP provisions. 

Because Congress has already given federal courts the jurisdiction to determine what monetary 

penalties are appropriate in the event of judicial enforcement for a violation of a SIP provision, 

neither the EPA nor states can alter or eliminate that jurisdiction by superimposing restrictions 

on that jurisdiction and discretion granted by Congress to the courts. Accordingly, pursuant to 

section 110(k) and section 110(l), the EPA cannot approve any such affirmative defense 

provision in a SIP. If such an affirmative defense provision is included in an existing SIP, the 

EPA has authority under section 110(k)(5) to require a state to remove that provision. 

Couching an affirmative defense provision in terms of merely defining whether or not the 

emission limitation applies and thus whether or not there is a “violation,” as suggested by some 

commenters, is also problematic. If there is no “violation” when certain criteria or conditions for 

an “affirmative defense” are met, then there is in effect no emission limitation that applies when 
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the criteria or conditions are met; the affirmative defense thus operates to create an exemption 

from the emission limitation. As explained in the February 2013 proposal, the CAA requires that 

emission limitations must apply continuously and cannot contain exemptions, conditional or 

otherwise. This interpretation is consistent with the decision in Sierra Club v. Johnson 

concerning the term “emission limitation” in section 302(k). Characterizing the exemptions as an 

“affirmative defense” runs afoul of the requirement that emission limitations must apply 

continuously. 

The EPA wishes to be clear that the absence of affirmative defense provisions in SIPs 

does not alter the legal rights of sources under the CAA. In the event of an enforcement action 

for an exceedance of a SIP emission limitation, a source can elect to assert any common law or 

statutory defenses that it determines are supported, based upon the facts and circumstances 

surrounding the alleged violation. Under section 113(b), courts have explicit authority to impose 

injunctive relief, issue compliance orders, assess monetary penalties or fees and impose any 

other appropriate relief. Under section 113(e), federal courts are required to consider the 

enumerated statutory factors when assessing monetary penalties, including “such other factors as 

justice may require.” For example, if the exceedance of the SIP emission limitation occurs due to 

a malfunction, that exceedance is a violation of the applicable emission limitation but the source 

retains the ability to defend itself in an enforcement action and to oppose the imposition of 

particular remedies or to seek the reduction or elimination of monetary penalties, based on the 

specific facts and circumstances of the event. Thus, elimination of a SIP affirmative defense 

provision that purported to take away the statutory jurisdiction of the federal court to exercise its 

authority to impose remedies does not disarm sources in potential enforcement actions. Sources 

retain all of the equitable arguments they could have made under an affirmative defense 
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provision; they must simply make such arguments to the reviewing court as envisioned by 

Congress in section 113(b) and section 113(e). 

Once impermissible SSM exemptions are removed from the SIP, then any excess 

emissions during such events may be the subject of an enforcement action, in which the parties 

may use any appropriate evidence to prove or disprove the existence and scope of the alleged 

violation and the appropriate remedy for an established violation. Any alleged violation of an 

applicable SIP emission limitation, if not conceded by the source, must be established by the 

party bearing the burden of proof in a legal proceeding. The degree to which evidence of an 

alleged violation may derive from a specific reference method or any other credible evidence 

must be determined based upon the facts and circumstances of the exceedance of the emission 

limitation at issue.394 Congress vested the federal courts with the authority to judge how best to 

weigh the evidence in an enforcement action. 

G. Anti-Backsliding Considerations 

The EPA recognizes that one important consideration for air agencies as they evaluate 

how best to revise their SIP provisions in response to this SIP call is the nature of the analysis 

that will be necessary for the resulting SIP revisions under section 110(k)(3), section 110(l) and 

section 193. Under section 110(l), the EPA is prohibited from approving any SIP revision that 

would interfere with any applicable requirement concerning attainment and reasonable further 

progress or any other requirements of the CAA. Section 193 prohibits states from modifying 

 

394 For example, the degree to which data from continuous opacity monitoring systems (COMS) 

is evidence of violations of SIP opacity or PM mass emission limitations is a factual question 

that must be resolved on the facts and circumstances in the context of an enforcement action. 

See, e.g., Sierra Club v. Pub. Serv. Co. of Colorado, Inc., 894 F. Supp. 1455 (D. Colo. 1995) 

(allowing use of COMS data to prove opacity limit violations). 
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regulations in place prior to November 15, 1990, unless the modification ensures equivalent or 

greater reductions of the pollutant. SIP revision must be evaluated for compliance with section 

110(l) and section 193 on the facts and circumstances of the specific revision. Section X of this 

notice provides three example scenarios in which a state might remove an impermissible SSM 

provision from its SIP, including how sections 110(l) and 193 considerations might apply. These 

examples are intended to provide general guidance on the considerations and the nature of the 

analysis that may be appropriate for different types of SIP revisions. Air agencies should contact 

their respective EPA Regional Offices for further recommendations and assistance concerning 

the analysis appropriate for specific SIP revisions involving changes in SSM provisions. 

XII. Environmental Justice Consideration 

The final action restates the EPA’s interpretation of the statutory requirements of the 

CAA. Through the SIP calls issued to certain states as part of this SIP call action under CAA 

section 110(k)(5), the EPA is only requiring each affected state to revise its SIP to comply with 

existing requirements of the CAA. The EPA’s action therefore leaves to each affected state the 

choice as to how to revise the SIP provision in question to make it consistent with CAA 

requirements and to determine, among other things, which of the several lawful approaches to 

the treatment of excess emissions during SSM events will be applied to particular sources. The 

EPA has not performed an environmental justice analysis for purposes of this action, because it 

cannot geographically locate or quantify the resulting source-specific emission reductions, but 

the EPA can expect only benefits from the action. 

XIII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: 

Improving Regulation and Regulatory Review 
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This action is a “significant regulatory action” that was submitted to the Office of 

Management and Budget (OMB) for review because it raises novel legal or policy issues. Any 

changes made in response to OMB recommendations have been documented in the docket. 

B. Paperwork Reduction Act (PRA) 

This action does not impose an information collection burden under the PRA. This action 

merely reiterates the EPA’s interpretation of the statutory requirements of the CAA and does not 

require states to collect any additional information. Through the SIP calls issued to certain states 

as part of this action under CAA section 110(k)(5), the EPA is only requiring each affected state 

to revise its SIP to comply with existing requirements of the CAA. 

C. Regulatory Flexibility Act (RFA) 

I certify that this action will not have a significant economic impact on a substantial 

number of small entities under the RFA. In making this determination, the impact of concern is 

any significant adverse economic impact on small entities. Any agency may certify that a rule 

will not have a significant economic impact on a substantial number of small entities if the rule 

relieves regulatory burden, has no net burden or otherwise has a positive economic effect on the 

small entities subject to this rule. This action will not impose any requirements on small entities. 

Instead, the proposed action merely reiterates the EPA’s interpretation of the statutory 

requirements of the CAA. Through the SIP calls issued to certain states as part of this SIP call 

action under CAA section 110(k)(5), the EPA is only requiring each affected state to revise its 

SIP to comply with existing requirements of the CAA. The EPA’s action therefore leaves to each 

affected state the choice as to how to revise the SIP provision in question to make it consistent 

with CAA requirements and to determine, among other things, which of the several lawful 
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approaches to the treatment of excess emissions during SSM events will be applied to particular 

sources. 

D. Unfunded Mandates Reform Act (UMRA) 

This action does not contain any federal mandate as described in UMRA, 2 U.S.C. 1531-

1538, and does not significantly or uniquely affect small governments. The action imposes no 

new enforceable duty on any state, local or tribal governments or the private sector. The 

regulatory requirements of this action apply to certain states for which the EPA is issuing a SIP 

call. To the extent that such affected states allow local air districts or planning organizations to 

implement portions of the state’s obligation under the CAA, the regulatory requirements of this 

action do not significantly or uniquely affect small governments because those governments have 

already undertaken the obligation to comply with the CAA. 

E. Executive Order 13132: Federalism 

This action does not have federalism implications. It will not have substantial direct 

effects on the states, on the relationship between the national government and the states, or on 

the distribution of power and responsibilities among the various levels of government. 

F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments 

This action does not have tribal implications as specified in Executive Order 13175. In 

this action, the EPA is not addressing any tribal implementation plans. This action is limited to 

states. Thus, Executive Order 13175 does not apply to this action. 

G. Executive Order 13045: Protection of Children from Environmental Health Risks and 

Safety Risks 

The EPA interprets Executive Order 13045 as applying only to those regulatory actions 

that concern environmental health or safety risks that the EPA has reason to believe may 
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disproportionately affect children, per the definition of “covered regulatory action” in section 2-

202 of the Executive Order. This action is not subject to Executive Order 13045 because, in 

prescribing the EPA’s action for states regarding their obligations for SIPs under the CAA, it 

implements specific standards established by Congress in statutes. 

H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect 

Energy Supply, Distribution or Use 

This action is not a “significant energy action” because it is not likely to have a 

significant adverse effect on the supply, distribution or use of energy. This action merely 

prescribes the EPA’s action for states regarding their obligations for SIPs under the CAA. 

I. National Technology Transfer and Advancement Act (NTTAA) 

This rulemaking does not involve technical standards. 

J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations 

The EPA believes the human health or environmental risk addressed by this action will 

not have potential disproportionately high and adverse human health or environmental effects on 

minority, low-income or indigenous populations. The rule is intended to ensure that all 

communities and populations across the affected states, including minority, low-income and 

indigenous populations overburdened by pollution, receive the full human health and 

environmental protection provided by the CAA. This action concerns states’ obligations 

regarding the treatment they give, in rules included in their SIPs under the CAA, to excess 

emissions during startup, shutdown and malfunctions. This action requires that certain states 

bring their treatment of these emissions into line with CAA requirements, which will lead to 

certain sources’ having greater incentives to control emissions during such events. 
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K. Determination Under Section 307(d) 

Pursuant to CAA section 307(d)(1)(V), the Administrator determines that this action is 

subject to the provisions of section 307(d). Section 307(d) establishes procedural requirements 

specific to rulemaking under the CAA. Section 307(d)(1)(V) provides that the provisions of 

section 307(d) apply to “such other actions as the Administrator may determine.” 

L. Congressional Review Act (CRA) 

This action is subject to the CRA, and the EPA will submit a rule report to each House of 

the Congress and to the Comptroller General of the United States. This action is not a “major 

rule” as defined by 5 U.S.C. 804(2). 

XIV. Judicial Review 

The Administrator determines that this action is “nationally applicable” within the 

meaning of section 307(b)(1) of the CAA. This action in scope and effect extends to numerous 

judicial circuits because the action on the Petition extends to states throughout the country. In 

these circumstances, section 307(b)(1) and its legislative history authorize the Administrator to 

find the rule to be of “nationwide scope or effect” and thus to indicate the venue for challenges to 

be in the D.C Circuit. Thus, any petitions for review must be filed in the U.S. Court of Appeals 

for the District of Columbia Circuit. 

In addition, pursuant to CAA section 307(d)(1)(V), the EPA is determining that this 

rulemaking action is subject to the requirements of section 307(d), which establish procedural 

requirements specific to rulemaking under the CAA. 

XV. Statutory Authority 

The statutory authority for this action is provided by CAA section 101 et seq. (42 U.S.C. 

7401 et seq.). 
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Page 53939 of 539 - State Implementation Plans: 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 

List of Subjects in 40 CFR Part 52 

Environmental protection, Affirmative defense, Air pollution control, Carbon dioxide, 

Carbon dioxide equivalents, Carbon monoxide, Excess emissions, Greenhouse gases, 

Hydrofluorocarbons, Incorporation by reference, Intergovernmental relations, Lead, Methane, 

Nitrogen dioxide, Nitrous oxide, Ozone, Particulate matter, Perfluorocarbons, Reporting and 

recordkeeping requirements, Startup, shutdown and malfunction, State implementation plan, 

Sulfur hexafluoride, Sulfur oxides, Volatile organic compounds. 

 

 

 

 

 

________________________ 

Dated: 

 

 

 

 

 

 

_________________________ 

Gina McCarthy, 

Administrator.