Technical Support Document

for

EPA's Notice of Proposed Rulemaking

for Revisions to the 

Nevada State Implementation Plan

Clark County Department of Air Quality

New Source Review Permitting Program, 

Including Minor Source, NSR and PSD programs

Section 0 Definitions

Section 12.0 Applicability, General Requirements and Transition Procedures

Section 12.1 Permit Requirements for Minor Sources

Section 12.2 Permit Requirements for Major Sources in Attainment Areas

Section 12.3 Permit Requirements for Major Sources in Nonattainment Areas

Section 12.4 Authority to Construct Application and Permit Requirements for Part 70 Sources

Section 12.7 Emission Reduction Credits (Subsection 12.7.5 only)

Rescind: Section 1 – Definitions, 

Section 11 – Ambient Air Quality Standards, and 

Section 24 – Sampling and Testing – Records and Reports

Prepared by Laura Yannayon

Reviewed by Gerardo Rios

Air Division, Permits Office

United States Environmental Protection Agency, Region IX

San Francisco, California

June 16, 2014
Table of Contents

Section Page

Introduction 1

NSR Program SIP Revision Submittals 1

Background 2

EPA Evaluation of NSR SIP Submittal 3

Rule Revisions to Address EPA Identified Disapproval Issues 3

Section 12.1 Permit Requirements for Minor Sources 3

Section 12.2 Permit Requirements for Major Sources in Attainment Areas 5

Section 12.3 Permit Requirements for Major Sources in Nonattainment Areas 8

Section 12.4 Authority to Construct Application & Permit Requirements for Part 70 Sources 11

Evaluation of EPA Recommended Revisions 12

Section 0 Definitions 12

Section 12.1 Permit Requirements for Minor Sources 12

Section 12.2 Permit Requirements for Major Sources in Attainment Areas 13

Section 12.4 Authority to Construct Application & Permit Requirements for Part 70 Sources 15

Evaluation of Additional Revisions 15

Section 0 Definitions 15

Section 1 Definitions 16

Section 12.0 Applicability, General Requirements and Transition Procedures 16

Section 12.1 Permit Requirements for Minor Sources 17

Section 12.2 Permit Requirements for Major Sources in Attainment Areas 18

Section 12.3 Permit Requirements for Major Sources in Nonattainment Areas 19

Section 12.4 Authority to Construct Application & Permit Requirements for Part 70 Sources 20

Rule Rescission Requests 20

Section 110(l) of the Act 21

Section 193 of the Act 22

Recommendations for Rule Revisions 22

EPA’s Proposed Action 22

Attachments 23
1

Introduction

Part C of title I of the Clean Air Act (CAA or Act) contains the provisions for the Prevention of 

Significant Deterioration (PSD) of air quality in areas designated as “attainment” or 

“unclassifiable” for the national ambient air quality standards (NAAQS). Part D of title I of the Act 

contains the requirements for areas designated “nonattainment” for any of the NAAQS. Both parts 

C and D of the Act require pre-construction permit programs for certain new or modified 

stationary sources of pollutants. The requirements under part C, referred to as “PSD New Source 

Review” (or simply PSD) apply to certain new or modified sources that emit pollutants for which 

the area is designated as attainment or unclassifiable and certain other (non-criteria) pollutants 

subject to regulation under the CAA. The requirements under part D, referred to as 

“Nonattainment NSR,” (or simply NSR) apply to certain new or modified sources of 

nonattainment pollutants in nonattainment areas. Considered collectively, the pre-construction 

permit requirements related to PSD and Nonattainment NSR are commonly referred to simply as 

“NSR.” Both of these programs apply to “major stationary sources” and “major modifications” as 

those terms are defined in 40 CFR Part 51 Subpart I. In addition to regulations for new and 

modified major stationary sources under parts C and D of title I, the CAA requires each state to 

include in its SIP a program to provide for the regulation of the construction and modification of 

any stationary source within the areas covered by the plan as necessary to assure that the NAAQS 

are achieved. These general pre-construction requirements are commonly referred to as “minor 

NSR.” See 40 CFR 51.160-51.164.

NSR Program SIP Revision Submittals

The revised rules that are the subject of this TSD were adopted by the Clark County Department of 

Air Quality (Clark or DAQ) on March 18, 2014 and submitted to EPA via the Nevada Division of 

Environmental Protection (NDEP) by a letter dated April 1, 2014. NDEP is the governor’s 

designee for submitting official revisions of the Nevada State Implementation Plan (SIP) to EPA. 

The rules (referred to as “Sections”) which NDEP has requested that EPA approve as revisions to 

the Clark County portion of the Nevada SIP are listed in Table 1. The rules which NDEP has 

requested EPA rescind from the Clark County portion of the Nevada SIP are listed in Table 2.

Table 1 – Submitted Rules

Section 

Number Section Title

Adoption 

Date

Submittal 

Date

0 Definitions 3/18/14 4/1/14

12.0 Applicability, General Requirements and Transition 

Procedures

3/18/14 4/1/14

12.1 Permit Requirements for Minor Sources 3/18/14 4/1/14

12.2 Permit Requirements for Major Sources in Attainment Areas 3/18/14 4/1/14

12.3 Permit Requirements for Major Sources in Nonattainment 

Areas Emission Offsets

3/18/14 4/1/14

12.4 Authority to Construct Application and Permit Requirements 

For Part 70 Sources

3/18/14 4/1/14

12.7 Emission Reduction Credits (Subsection 12.7.5 only) 5/18/10 4/1/14
2

Table 2 –Rules to be Rescinded

Section 

Number Section Title

Repealed 

Date

Submittal 

Date

1 Definitions 3/18/14 4/1/14

11 Ambient Air Quality Standards 4/5/11 4/1/14

24 Sampling and Testing – Records and Reports 3/16/10 4/11/14

Sections 0, 12.0, 12.1, 12.2, 12.3, 12.4, and subsection 12.7.5 of Section 12.7 collectively, 

establish a program for reviewing and permitting new or modified stationary sources in Clark 

County.

1 The SIP revision submittals are collectively referred to herein as the “NSR SIP 

submittal” or “submitted NSR rules.”

Background

On October, 18, 2012, EPA finalized a limited approval and limited disapproval of 6 Clark County 

rules (Sections 0, 12.0, 12.1, 12.2, 12.3, and 12.4) intended to implement their New Source Review 

(NSR) programs. See 77 FR 64039. The effect of this action was to incorporate these rules into the 

SIP and to trigger a sanctions clock with respect to certain provisions of the rules that did not 

satisfy the requirements of section 110 and title I, part D of the CAA. This sanctions clock expired 

on May 18, 2014, eighteen months after the effective date of EPA’s final disapproval action.

Accordingly, the provisions of 40 CFR 52.31(e)(1) – Offset Sanction, requiring a 2:1 offset ratio 

for any nonattainment pollutant that otherwise triggers offset requirements, is currently in effect. 

When EPA publishes a proposed notice of rulemaking for the submitted NSR rules, EPA intends 

to also publish an interim final determination which will effectively stay the offset sanction and the 

sanctions clock, until EPA takes a final rulemaking action to permanently stop this sanctions 

clock. Clark’s submitted revisions of these same rules are intended to address these previously 

identified rule deficiencies and allow EPA to permanently stop the applicable sanctions clock.

For additional detailed information regarding these rules, the reader is directed to EPA’s proposed 

rulemaking action dated July 24, 2012 and the Technical Support Document (TSD) dated July 11, 

2012. See 77 FR 43206. Because our 2012 rulemaking evaluated these same rules collectively as a 

NSR program and only found minor deficiencies, this TSD focuses only on the revisions made to 

these rules since we evaluated them in 2012. 

The CAA defines a “nonattainment” area as any area that does not meet (or that contributes to 

ambient air quality in a nearby area that does not meet) the national primary or secondary NAAQS 

for a pollutant. CAA 107(d)(1)(A)(i). Clark County is currently designated as attainment or 

unclassifiable for all NAAQS pollutants, with one exception: the Las Vegas Valley area within 

Clark County is designated and classified as “serious” nonattainment for the PM10 NAAQS. 40 

CFR 81.329. EPA has determined, however, that this nonattainment area is attaining the PM10

standard. See 75 FR 45485 (August 3, 2010) (Determination of Attainment for PM10 for the Las 

Vegas Valley Nonattainment Area, NV). Thus, although this area remains designated 

 1 Section 12.4 also contains requirements to address the CAA title V requirements for operating permit programs, but 

we are not evaluating the rule for title V purposes at this time. 
3

“nonattainment” for PM10 until such time as EPA redesignates it to “attainment” consistent with 

the requirements of CAA section 107(d)(3)(E), because of the determination of attainment, the 

State of Nevada’s obligations under the CAA to submit attainment demonstrations and other 

planning requirements related to attainment of this NAAQS is suspended for so long as the areas 

continue to attain the PM10 NAAQS. Because the area remains designated “nonattainment” for 

PM10, Clark is still required to implement a SIP-approved NSR program for at least the Las Vegas 

Valley area that applies to PM10 and its precursors. See 40 CFR 51.165(a)(1)(xxxvii)(C).

EPA Evaluation of NSR SIP Submittal 

This section of the TSD provides detailed summaries of the revisions made to each of the 

submitted rule Sections. It is broken down into four parts; (1) revisions made to address EPA 

identified disapproval issues, (2) revisions made to address EPA recommendations, (3) additional

revisions made to the submitted rules, and (4) DAQs request to rescind certain rules from the 

existing SIP.

Rule Revisions to Address EPA Identified Disapproval Issues

This section of the TSD provides a summary of each disapproval issue identified by EPA 

(including a reference to the issue discussion in our previous TSD entitled “Technical Support 

Document for EPA's Notice of Proposed Rulemaking for Revisions to the Nevada State 

Implementation Plan Clark County Department of Air Quality & Environmental Management 

New Source Review Permitting Program, Including Minor Source, NSR and PSD programs”; 

dated July 11, 2012), a description of the revision made to address the disapproval issue and EPA’s 

evaluation as to whether the revision fully resolves the identified disapproval issue.

Section 12.1: Permit Requirements for Minor Sources

1. Section 12.1 Disapproval Issue (TSD page 11-12, Item 1(a))

Subsection 12.1.4.1(c) requires that each minor source permit issued by Clark County include

emission limitations that ensure “[t]he ambient air quality standards will be attained or 

maintained” and appears to depend upon DAQ’s definition of “ambient air quality standards in 

Section 11,” which does not include the 2006 24-hour PM2.5 NAAQS of 35 μg/m3 or the 2008 

Pb NAAQS of 15 μg/m3 (rolling 3-month average). 

To address this disapproval issue, DAQ made the following revisions: 

• Revised Section 0 as follows: “Air Quality Standard” now refers to a newly added

definition of “National Ambient Air Quality Standard”, which incorporates by reference all 

NAAQS in 40 CFR Part 50, including definitions, scope, reference conditions and 

appendices as of the most recent CFR codification (July 1 2012). 

• Revised Section 12.1.4.1(c) (“Permit Content”) to require emission limitations that ensure 

the “National Ambient Air Quality Standards” are attained and maintained. 

• Requested that Section 11 be rescinded from the SIP, as these provisions are now contained 

in submitted Section 12 rules. Section 11 was previously repealed locally.

EPA evaluation: These revisions correct the identified disapproval issue by referencing the 
4

NAAQS, rather than the ambient air quality standards previously listed in Section 11.

2. Section 12.1 Disapproval Issue (TSD page 13, Item 1(c))

Subsection 12.1.3.6(a)(5) provides that an applicant may identify specific portions of a permit

that it wants to be federally enforceable. This is not consistent with CAA requirements, as all

conditions of a permit issued pursuant to a SIP-approved permit program are federally 

enforceable.

To address this disapproval issue DAQ made the following revisions: 

• Deleted subsection 12.1.3.6(a)(5).

EPA evaluation: This revision corrects the identified disapproval issue by removing the 

inconsistent language. 

3. Section 12.1 Disapproval Issue (TSD page 14, Item 1(d))

Neither Section 12.1 nor Section 12.4 contain a provision addressing, for minor stationary

sources, the requirement in 40 CFR 51.160(d) to “provide that approval of any construction or

modification must not affect the responsibility on the owner or operator to comply with 

applicable portions of the control strategy.”

To address this disapproval issue DAQ made the following revisions: 

• Added new subsection (12.0.4) that states: “No approval of an authority to construct or 

authority to operate permit...shall affect the responsibility of the permittee to comply with 

the requirements of the applicable portions of the Nevada SIP.”

EPA evaluation: This revision corrects the identified disapproval issue by adding the missing 

provision. 

4. Section 12.1 Disapproval Issue (TSD page 15, Item 1(e))

Section 12.1 provides (in subsection 12.1.2(a)) an exemption from permitting requirements 

“for construction and operation of any emission units or performance of any of the activities 

listed in Sections 12.1.2(c) or 12.5.2.5.” Section 12.5 addresses the operating permit 

requirements of Title V of the CAA. Because Section 12.5 is neither approved into the SIP nor 

included in the NSR SIP submittal, we cannot conclude that this exemption is appropriate for 

minor NSR purposes.

To address this disapproval issue DAQ made the following revisions: 

• Revised Section 12.1 to include an “Appendix A,” which is the “Insignificant Activities” 

list also found in Section 12.5.2.5. The reference to Section 12.5.2.5 in Section 12.1.2(a) 

has been revised to reference Appendix A.

EPA evaluation: This revision corrects the identified disapproval issue by specifically 

including the list of exempt permit requirements in Section 12.1 Appendix A. EPA has 

reviewed the list of “Insignificant Activities” which exempts these activities from permit 
5

requirements. We concur with Clark’s assessment that this list excludes from review only less 

environmentally significant sources and modifications, based on Clark’s evaluation of the 

insignificant portion of total stationary source emissions attributed to minor sources.2

5. Section 12.1 Disapproval Issue (TSD page 16, Item 1(d))

The applicability provisions in Section 12.1 (in particular the definition of “minor source” in

subsection 12.1.1(c)) are deficient, as they do not address sources of PM2.5 or PM2.5 precursor

emissions.

To address this disapproval issue DAQ made the following revisions: 

• Inserted thresholds for PM2.5 into the Section 12.1.1(c) definition of “Minor Source” and 

the Section 12.1.1(g) definition of “Significant.” PM2.5 precursors are addressed by the 

definition of “regulated air pollutant” in Section 0. 

EPA evaluation: This revision corrects the identified disapproval issue by adding appropriate 

“Minor Source” and “Significant” applicability thresholds for PM2.5. The new definition of 

PM2.5 clarifies that it also includes precursors, including condensables.

6. Section 12.1 Disapproval Issue (TSD page 19-20, Item 5)

Section 12.1 does not contain any provisions designed to ensure that the air quality impacts of

stationary sources are not underestimated due to stack heights that exceed good engineering

practice or air dispersion modeling techniques that do not satisfy the criteria in 40 CFR

51.118(b), as required by 40 CFR 51.164.

To address this disapproval issue DAQ made the following revisions: 

• Added Section 12.0.5 (“Stack Height”) which applies to all Section 12 permits, including 

minor sources.

EPA evaluation: The language contained in new Section 12.0.5 corrects the identified 

disapproval issue by specifying that the degree of emission limitation required of any source 

shall not be affected by so much of the source’s stack height that exceeds good engineering 

practice as determined by the procures specified in 40 CFR 51.118; which is what is required 

by 40 CFR 51.164.

Section 12.2: Permit Requirements for Major Sources in Attainment Areas (AKA: 

Prevention of Significant Deterioration (PSD))

1. Section 12.2 Disapproval Issue (TSD page 21, Item 2.A.)

The definition of “allowable emissions” in subsection 12.2.2(b) provides for calculation of 

emissions rates based on “practically enforceable” permit limits, in lieu of federally 

enforceable limits, but it does not provide criteria by which a limit will be judged to be 

 2 See United States Environmental Protection Agency, Region IX Air Division, Technical Support Document for 

EPA's Notice of Proposed Rulemaking for revisions to the Nevada State Implementation Plan, Clark County 

Department of Air Quality & Environmental Management, New Source Review Permitting Program (July 11, 2012), 

pp. 14-15.
6

“practically enforceable” by DAQ. This definition also allows for permit conditions with 

“future compliance dates” to be used to determine allowable emissions, which is not consistent 

with EPA’s definition of the term in 40 CFR 51.166(b)(16).

To address this disapproval issue DAQ made the following revisions: 

• DAQ elected to define “Enforceable as a Practical Matter” in Section 0 and make 

“Practically Enforceable” an explicit synonym. 

• Retained the “future compliance date” language in the regulation based on the fact that this 

language is still found in the 40 CFR Part 51.166(b)(16) definition of “allowable 

emissions”.

EPA evaluation: This revision corrects the identified disapproval issue regarding the use of the 

term “practically enforceable” by adding a definition for “Enforceable as a Practical Matter” in 

Section 0 and making “Practically Enforceable” an explicit synonym. EPA also concurs that 

the language regarding future compliance dates is included in our regulations, and therefore 

the inclusion of this language was not a deficiency. 

2. Section 12.2 Disapproval Issue (TSD pages 21-22, Item 2.A. and Final FR Notice page 

64044)

The definition of “baseline actual emissions” for non-EUSGUs in 12.2.2(c)(2)(D) is internally 

inconsistent and confusing. The subsection uses the terms “must currently comply” and 

“comply as of the particular date” interchangeably, which EPA disapproves.

To address this disapproval issue DAQ made the following revisions: 

• Revised Section 12.2.2(c)(2)(D) by deleting “currently” and inserting “as of the particular 

date” after “comply.”

EPA evaluation: This revision corrects the identified disapproval issue, by using the phrase “as 

of a particular date” consistently in the definition of “baseline actual emissions.” 

3. Section 12.2 Disapproval Issue (TSD pages 22-23, Item 2.A.)

The definition of “net emissions increase” (NEI) in subsection 12.2.2(ii) contains three 

subparagraphs under 12.2.2(ii)(1)(C) for calculating “actual emissions after the 

contemporaneous project” which are not consistent with EPA’s definition of NEI in 40 CFR 

51.166(b)(3). EPA’s definition of NEI allows for consideration of those emission increases 

and decreases that are “contemporaneous” with the project under review but does not call for 

any assessment of actual emissions after a contemporaneous project. See 40 CFR 51.166(b)(3). 

Additionally, subparagraph (1)(C)(ii) allows for the calculation of NEI to be based on 

“projected actual emissions” in certain cases, which is not allowed under EPA’s definition of 

NEI in 40 CFR 51.166(b)(3).

To address this disapproval issue DAQ made the following revisions: 

• Deleted the three subparagraphs under 12.2.2(ii)(1)(C).
7

EPA evaluation: This revision corrects the identified disapproval issues by removing the 

objectionable language. The definition of “net emissions increase” is now consistent with the 

language in 51.166(b)(3).

4. Section 12.2 Disapproval Issue (TSD pages 23-24, Item 2.A.)

The definition of “major modification” in subsection 12.2.2(dd) is not consistent with EPA’s 

current approach to the treatment of fugitive emissions in applicability determinations for 

major modifications.

To address this disapproval issue DAQ made the following revisions: 

• Deleted the word “not” from the definition along with the categorical source language, i.e., 

“...unless the major stationary source is a categorical stationary source...” now reads 

“...fugitive emissions shall be included...” (emphasis added).

EPA evaluation: This revision corrects the identified disapproval issue by revising the 

language to now require fugitive emissions to be considered for major modification 

applicability determinations.

5. Section 12.2 Disapproval Issue (TSD page 24-25, Item 2.B.)

The definition of “regulated NSR pollutant” in subsection 12.2.2(pp) does not satisfy current 

requirements regarding identification of precursors and treatment of “condensable particular 

matter” in PSD applicability determinations.

To address this disapproval issue DAQ made the following revisions: 

• Inserted missing 40 CFR 51.166(b)(49)(i) language defining precursors into Section 

12.2.2(pp). 

• Added federal condensable language to Section 0 definitions of “PM2.5” and “PM10.”

EPA evaluation: These revisions correct the identified disapproval issue by adding the specific

missing language. 

6. Section 12.2 Disapproval Issue (TSD page 30, Item 15)

One provision governing “Plantwide Applicability Limits” (PALs) in subsection 12.2.19 is not

entirely consistent with EPA’s requirement regarding the time frame for adjustment of a PAL 

to address compliance dates that occur during the PAL effective period.

To address this disapproval issue DAQ made the following revisions: 

• Revised Section 12.2.19.10(e) to read: “... the PAL shall be adjusted at the time of the PAL 

permit renewal or Part 70 Operating Permit renewal, whichever occurs first.”

EPA evaluation: This revision corrects the identified disapproval issue by adding the specific

missing language.
8

7. Section 12.2 Disapproval Issue (TSD page 53)

Neither Section 12.2 nor Section 12.4 contains a provision addressing the requirement of 40 

CFR 51.160(d) to provide that approval of any construction or modification will not affect the 

responsibility of the owner or operator to comply with applicable portions of the control 

strategy.

To address this disapproval issue DAQ made the following revisions: 

• Added new Applicability subsection (12.0.4) that states: “No approval of an Authority to 

Construct or authority to operate permit issued pursuant to Section 12 shall affect the 

responsibility of the permittee to comply with the requirements of the applicable portions 

of the Nevada SIP. 

EPA evaluation: This revision corrects the identified disapproval issue by adding the missing 

provision. 

Section 12.3: Permit Requirements for Major Sources in Nonattainment Areas (AKA: 

Nonattainment New Source Review (NNSR))

1. Section 12.3 Disapproval Issue (TSD page 31-32, Item 1)

The requirements for offsets in subsection 12.3.6 do not contain adequate provisions, 

consistent with CAA Section 173(a)(1), to assure that emission offset calculations are based on 

the same emissions baseline used in the demonstration of reasonable further progress for the 

relevant NAAQS pollutant (where applicable) and also fail to satisfy EPA’s NSR criteria for 

offset calculations, as required by CAA Section 173(a)(1)(A) and 40 CFR 51.165(a)(3).

To address this disapproval issue DAQ made the following revisions: 

• Revised Section 12.3.6.5 (“Quantity”) to add subsection (d), which requires that the 

baseline for determining credit for emissions reductions be based on the emission limit 

under the SIP, including the demonstration of Reasonable Further Progress in effect when 

the application was filed, except where the demonstration is based on actual emissions or

there is no emission limitation for that source category in the SIP, in which case actuals 

shall be used. 

EPA evaluation: This revision corrects the identified disapproval issue by adding language that 

mirrors the provisions found in 40 CFR 51.165(a)(3).

2. Section 12.3 Disapproval Issue (TSD page 32, Item 1)

EPA noted that due to Clark County’s recent reclassification to a marginal ozone 

nonattainment area (See 77 FR 28424 May 14, 2012), the offset ratios listed in Table 12.3-1 

must be revised to at least 1.1:1. In addition, EPA stated that the term “Nonattainment without 

Designation” is confusing and suggested revising it. 

To address this disapproval issue DAQ made the following revisions: 

• Revised Table 12.3-1 to include a 1.1:1 offset ratio for a marginal ozone nonattainment 

area (for NOx and VOCs) and deleted the “Nonattainment without Designation” term. 
9

EPA evaluation: EPA notes that our redesignation of Clark County to attainment for the 1997 

8- hour ozone NAAQS took effect on February 7, 2013 (78 FR 1149), which resolves this 

disapproval issue. However, the revisions ensure that Section 12.3 will adequately address 

offset requirements if Clark is ever designated a Marginal or Moderate Ozone nonattainment 

area in the future. 

3. Section 12.3 Disapproval Issue (TSD page 33, Item 3)

Section 12.3 does not contain provisions to assure that emissions increases from new or 

modified major stationary sources are offset by real reductions in “actual emissions,” as 

required by CAA Section 173(c)(1), because it does not contain adequate criteria for 

determining whether certain emission reductions may qualify for use as offsets. Subsection 

12.3.6 references a separate rule (Section 12.7) for important criteria related to this 

determination, but Section 12.7 is neither approved into the SIP nor included in the NSR SIP 

submittal; therefore, it cannot provide an appropriate basis for evaluating emission reductions 

to satisfy the requirements in CAA Section 173(c)(1).

To address this disapproval issue DAQ made the following revisions: 

• Revised Sections 12.3.6.2(b) and (c) to incorporate by reference Section 12.7.5, and 

submitted Section 12.7.5 separately, for incorporation into the Clark county portion of the

Nevada SIP.

EPA evaluation: These revisions correct the identified disapproval issues by incorporating the 

missing language into Section 12.3.6.2 by reference, and submitting the incorporated language 

as part of the SIP submittal.

4. Section 12.3 Disapproval Issue (TSD page 33-34, Item 3)

Section 12.3.6.3 allows for interpollutant trades between VOC and NOx emission reductions to

satisfy offset requirements for ozone and interpollutant trades among PM2.5, SO2, and NOx

emission reductions to satisfy offset requirements for PM2.5. These provisions do not satisfy 

EPA’s regulatory and policy criteria for approval of such interpollutant trades or interprecursor 

trading hierarchies.

To address this disapproval issue DAQ made the following revisions: 

• Added language to Section 12.3.6.3(b) to clarify that the Control Officer may approve 

interpollutant offset trades for pollutant precursors, except for PM2.5 precursors, based on 

an air quality analysis. The new language also clarified that PM10 may not be used to offset 

VOC or NOx in an ozone nonattainment area; that compounds excluded from the definition 

of VOC cannot be used as offsets for VOCs; and that all interpollutant emission offsets 

proposed to be used at a major source require written approval from EPA. 

• Added new Section 12.3.6.3(c) to clarify that interpollutant PM2.5 offsets may only be used 

if specific interpollutant offset ratios are approved in a PM2.5 attainment plan.

EPA evaluation: These revisions are consistent with EPA policy on interpollutant trades and 
10

EPA regulations on PM2.5 interpollutant offsets at 51.165(a)(11), and thus correct the 

identified disapproval issues by appropriately clarifying when interpollutant offsets may be 

used for specific types of pollutants.

5. Section 12.3 Disapproval Issue (TSD page 34, Item 4)

The definition of “surplus” must be revised to ensure that emission reductions required by 

CAA Sections 111 or 112 standards are not treated as surplus.

To address this disapproval issue DAQ made the following revisions: 

• Added language to both the Sections 0 and 12.3.2(qq) definitions of “Surplus” to clarify 

that emission reductions required by an applicable NSPS or NESHAP are not considered 

surplus, unless Clark has not taken credit for NESHAP required emission reductions in 

their attainment demonstration or maintenance plan. 

EPA evaluation: These revisions correct the identified disapproval issue by appropriately 

clarifying when emission reductions otherwise required by NSPS or NESHAP can be 

considered surplus emission reductions. 

6. Section 12.3 Disapproval Issue (TSD Page 36-37, Item 8.A)

The definition of “major modification” in subsection 12.3.2(x) requires exclusion of two 

specific types of physical or operational changes that EPA’s definition of “major 

modification” in 40 CFR 51.165(a)(1)(v) does not exclude: (1) the installation or operation of a 

permanent Clean Coal Technology Demonstration Project that constitutes repowering; and (2) 

the reactivation of a very clean coal-fired electric utility steam generating unit. Although such 

exemptions are acceptable for purposes of PSD review (see 40 CFR 51.166(b)(2)(iii) and 

(b)(36)), such exemptions are not permissible for nonattainment NSR purposes.

To address this disapproval issue DAQ made the following revisions: 

• Deleted subsections (I) and (J) from the definition of “major modification” in 12.3.2(x). 

EPA evaluation: This revision corrects the identified disapproval issue by removing the 

objectionable language. The definition of Major Modification is now consistent with the 

language in 51.165(a)(1)(v).

7. Section 12.3 Disapproval Issue (TSD Page 37, Item 8.A and TSD Pages 39-40, Item 14)

The definition of “major modification” in subsection 12.3.2(x) is not consistent with EPA’s 

current approach to the treatment of fugitive emissions in applicability determinations for 

major modifications. As discussed above with respect to the definition of this same term in 

Section 12.2, EPA has administratively stayed 40 CFR 51.165(a)(1)(v)(G), effective March 

30, 2011 (76 FR 17548), which had the effect of reverting the treatment of fugitive emissions 

in applicability determinations to the approach that applied prior to the Fugitive Emissions 

Rule, thus requiring that fugitive emissions be included in “major modification” applicability 

determinations for all source categories.

To address this disapproval issue DAQ made the following revisions: 
11

• In subsection (5) of definition of “major modification”, removed the word “not” to change 

the meaning to require fugitives to be counted in major modification determinations.

EPA evaluation: This revision corrects the identified disapproval issue by revising the 

language to now require fugitive emissions to be considered for all major modification 

applicability determinations.

8. Section 12.3 Disapproval Issue (TSD page 37, Item 8.A)

The definition of “regulated NSR pollutant” in subsection 12.3.2(ii) does not satisfy current 

requirements regarding “condensable particular matter” in NSR applicability determinations.

EPA’s definition of “regulated NSR pollutant” in 40 CFR 51.165(a)(xxxvii)(D) includes a 

paragraph stating that on or after January 1, 2011, “gaseous emissions from a source or activity 

which condense to form particulate matter at ambient temperatures” (i.e., condensable 

particular matter) must be accounted for in applicability determinations and in establishing 

emissions limitations for PM, PM2.5, and PM10 in NSR permits.

To address this disapproval issue DAQ made the following revisions: 

• Inserted missing 40 CFR 51.165(a)( xxxvii)(D) language defining precursors into Section 

12.3.2(ii). 

• Added language to Section 0 definitions of “PM2.5” and “PM10” to clarify that condensable 

emissions are part of these pollutants.

EPA evaluation: These revisions correct the identified disapproval issue by adding the specific 

missing language. 

9. Section 12.3 Disapproval Issue (TSD page 38, Item 11)

Section 12.3 does not contain provisions, pursuant to 40 CFR 51.118(a), to assure that the 

degree of emission limitation required of any source for control of any air pollutant must not be 

affected by a stack height that exceeds good engineering practice. Provisions to meet these 

requirements and 40 CFR 51.164 are missing.

To address this disapproval issue DAQ made the following revisions: 

• Added Section 12.0.5 (“Stack Height”) which applies to all Section 12 permits. 

EPA evaluation: This revision corrects the identified disapproval issue by adding the missing 

provision. 

Section 12.4: Authority to Construct Application and Permit Requirements for Part 70

Sources

1. Section 12.4 Disapproval Issue (TSD page 43, Item 1(d), “Legally Enf. Procedures”):

Section 12.4 does not contain a provision to satisfy the 40 CFR 51.160(d) requirement that 

approval of any construction or modification not affect the responsibility of the owner or 

operator to comply with applicable portions of the control strategy.
12

To address this disapproval issue DAQ made the following revisions: 

• Added new subsection (12.0.4) that states: “No approval of an Authority to Construct or 

authority to operate permit ...shall affect the responsibility of the permittee to comply with 

the requirements of the applicable portions of the Nevada SIP. 

EPA evaluation: This revision corrects the identified disapproval issue by adding the missing 

provision. 

2. Section 12.4 Disapproval Issue (TSD page 46, Item 5):

Section 12.4 does not contain any provisions designed to ensure that the air quality impacts of 

stationary sources are not underestimated due to stack heights that exceed good engineering 

practice or air dispersion modeling techniques that do not satisfy the criteria in 40 CFR 

51.118(b), as required by 40 CFR 51.164.

To address this disapproval issue DAQ made the following revisions: 

• Added Section 12.0.5 (“Stack Height”) which applies to all Section 12 permits. 

EPA evaluation: This revision corrects the identified disapproval issue by adding the missing 

provision. 

Evaluation of EPA Recommended Revisions

This section of the TSD provides a summary of each recommendation made by EPA in our 

previous TSD3

, a description of the revision made to address the recommendation, and EPA’s 

evaluation as to whether the revision is acceptable.

Section 0: Definitions

1. Section 0 definition of Potential To Emit (TSD page 51): Recommended establishing criteria 

for determining what constitutes “enforceable as a practical matter.”

DAQ added a definition for the term “enforceable as a practical matter” in Section 0 by using 

the same criteria as in Section 12.1.7. This definition is acceptable to EPA. 

2. Section 0 definition of ambient air quality standard (TSD page 51): Recommended 

clarifying that the term means National Ambient Air Quality Standard.

DAQ revised the definition of the term in both Sections 0 and 12.1.4.1(c), per EPA 

recommendation. EPA has reviewed this change and finds it is acceptable.

Section 12.1: Permit Requirements for Minor Sources

1. Section 12.1.6(d) (TSD page 52): Recommended revising subsection (d)(5) to ensure that the 

 3 See “Technical Support Document for EPA's Notice of Proposed Rulemaking for Revisions to the Nevada State 

Implementation Plan Clark County Department of Air Quality & Environmental Management New Source Review 

Permitting Program, Including Minor Source, NSR and PSD programs”, July 11, 2012.
13

change allowed under this provision does not allow changes that result in emission increases 

at or above the significant level. Also, correct the typo in 12.1.6(b).

DAQ added this phrase to Section 12.1.6(d)(5) “...and less than a significant amount (as 

defined in Section 12.1.1(g))” and corrected the subsection reference in 12.1.6(b) from “(E)” 

to “(D)” as recommended. EPA has reviewed these changes and finds they are acceptable.

Section 12.2: Permit Requirements for Major Sources in Attainment Areas (AKA: 

Prevention of Significant Deterioration (PSD))

1. Definition of PSD Permit, Section 12.2.2(ll); (TSD page 23-24): The last sentence in the 

federal definition of PSD permit is missing. Recommend adding the missing sentence.

DAQ added the sentence from 40 CFR 51.166(b)(42), as follows: “Any permit issued under 

such a program is a major NSR permit.” EPA has reviewed this change and finds it is 

acceptable.

2. PM2.5 SILs and SMCs (TSD page 25-26): EPA pointed out that the rule lacked SILs and 

SMCs for PM2.5, as required by an October 2010 rulemaking (75 FR 64864). Since the 

deadline for incorporating these requirements had not yet passed when EPA wrote its TSD, this 

was not a disapproval issue, but would be one if not addressed in DAQ’s next submittal. 

DAQ revised the definitions of “baseline area” (12.2.2(d)), “major source baseline date” 

(12.2.2(ee)), and “minor source baseline date” (12.2.2(gg)) in accordance with the 

requirements of the referenced rulemaking. In light of the recent D.C. Circuit Court decision 

on SILs and SMCs, DAQ has retained the listing for PM2.5 listed in Table 12.2-2, but lists a 

Significant Monitoring threshold of 0 μg/m3. No PM2.5 significant impact level is listed in 

Table 12.2-3, consistent with the court’s decision that such thresholds were not automatically 

demonstrably protective of the NAAQS.

EPA has reviewed these changes and finds they are consistent with the court’s ruling and are 

therefore acceptable.

3. New PM2.5 program requirements (TSD page 26): EPA pointed out that subsections 12.2.3 

(“Ambient Air Increments”) and 12.2.4 (“Ambient Air Ceilings”) would need to be revised to 

reflect the new PM2.5 implementation requirements (75 FR 64864). 

DAQ made the following revisions to address this recommendation: 

• Revised Table 12.2-1, “Increment Limits,” in Section 12.2.3 to add annual and 24-hour 

PM2.5 limits for Class I, II, and III airsheds. 

• Verified that the Section 12.2.4 thresholds are adequate as is. 

• Revised Table 12.2-4, “Maximum Allowable Pollutant Increases,” in Section 12.2.15.4 to 

include annual and 24-hour limits for PM2.5. 

• Revised Table 12.2-2 to add a PM2.5 threshold of 0 and the clarifying comment, consistent 
14

with 78 FR 73698. 

EPA has reviewed these changes and finds they are acceptable.

4. Section 12.2 definition of baseline actual emissions (TSD page 52): Suggested re-lettering

subsection to ensure clarity.

DAQ re-lettered the subsection in accordance with suggestion. EPA has reviewed this change 

and finds it is acceptable.

5. Section 12.2.15.1, “Notice to EPA” (TSD page 52): Suggested revising this provision to

provide that NDEP be sent the same copy of the draft permit application this subsection

requires be sent to EPA.

DAQ stated that they declined to make this change after discussing the issue with NDEP. They 

stated that each agency knows the issues well enough to consult with the other when 

circumstances warrant, so incorporating this notification into Section 12.2 was unnecessary.

While DAQ did not make the suggested change, this is not a disapproval issue. 

6. Section 12.2.19.2(a), “Definitions” (TSD page 52): Suggested revising the introductory

paragraph to clarify the order of use of the applicable definitions.

DAQ revised this section by adding language stating that a given term will be used as defined 

in Section 12.2.2, as well as Section 0, Section 12.4, or the CAA. DAQ also deleted references

to Clark County Code and the Nevada Revised Statutes to eliminate potential non- SIP 

references. EPA has reviewed these changes and finds them acceptable.

7. Major Stationary Source definition (TSD page 37): EPA noted that the definition of “major 

stationary source” contains a typo, in that subsections (2)(A) and (2)(B) should be renumbered 

as paragraphs (3) and (4), since they are not subsections of Section (2).

DAQ revised the section as suggested. EPA has reviewed this change and finds it is acceptable.

8. Size of municipal incinerators (TSD page 38): EPA noted that the threshold of 50 tpd for 

municipal incinerators within the categorical stationary source definition should be 250 tpd

(see 40 CFR 51.165(a)(1)(iv)(C)(8)).

DAQ pointed out that while the cited statute lists the threshold at 250 tons per day (tpd), the 

CFR is out of date. The definition of “major emitting facility” at section 169(1) of the Clean 

Air Act (42 U.S.C. § 7479(1)) was amended by section 305(b) of the Clean Air Act 

Amendments of 1990 (P.L. 101-549) to reduce the size threshold from 250 tpd to 50 tpd. While 

this change took effect immediately upon passage of the 1990 Amendments, EPA has not yet 

updated the NSR implementing regulations at 40 CFR 51.165(a)(1)(iv)(C)(8). EPA concurs 

that the proper threshold is 50 tpd. 
15

Section 12.4: Authority to Construct Application and Permit Requirements for Part 70 Sources

1. Section 1(b), “Legally Enforceable Procedures” (TSD page 42-43)

Section 12.4 does not contain a provision that explicitly authorizes Clark County to prevent 

construction if the submitted documents do not adequately make the specified demonstrations.

To address this issue DAQ added subsection (3) to Section 12.4.3.1(d) (“Application 

Processing Procedures”), that states: “(3) The Control Officer shall not issue an authority to 

construct or permit to operate unless, after the date the application is determined to be 

complete, the Control Officer determines that the new or modified source will meet all 

applicable requirements of Section 12.” This revision corrects the identified issue by adding 

the missing provision. EPA finds this revision acceptable.

Evaluation of Additional Revisions

This section of the TSD summarizes the additional revisions DAQ has made to the submitted rules 

since EPA’s 2012 rule review and evaluation, and provides EPA’s analysis regarding 

approvability of the revised provision. 

Section 0 – Definitions

1. Added a definition of “Ambient Air Quality Standard” and “Air Quality Standard” to clarify 

that it has the same meaning as the Section 0 definition of “National Ambient Air Quality 

Standard”. This defines what is meant when the AQRs refer to the above terms and reflects that 

the AQRs no longer refer to the repealed Section 11 for the definition of the term.

2. Added a definition of “enforceable as a practical matter” to clarify the components of the 

definition.

3. Added a clarifying sentence to the definitions of “PM2.5” and “PM10” that meets the federal 

requirement to include condensables that form particulate matter at ambient temperatures in 

the definition.

EPA evaluation: These revisions regarding defined terms are consistent with EPA’s definition 

or other revisions made to correct disapproval issues discussed earlier in this document. These 

revisions are acceptable.

4. Added definition of “Operating Permit” to clarify that permits issued by specific AQRs are 

consistent with the authority granted in state law.

5. Added a definition of “Responsible Official” to ensure that it can be used for any purpose 

within the AQRs. Currently, it is an AQR Section 12.5-specific definition, but it is used for 

reporting and notification requirements as well. The term is defined in Section 0 exactly as it is 

defined in Section 12.5.

6. Deleted the term “major” from the definition of “Secondary Emissions” to ensure that the 

definition is applicable to modifications at both minor and major sources.

7. Added compounds listed as compounds 45-59 to the definition of “Volatile Organic 

Compound” to ensure the definition meets the current federal definition of the term.
16

EPA evaluation: These revisions regarding defined terms are either consistent with EPA 

defined terms (VOC, Responsible Official) or are otherwise acceptable revisions. 

8. Added language to the Section 0 definition of “Surplus” to clarify any emission reductions 

required by a NSPS or a NESHAP, are not creditable as offsets, unless the state has not taken 

credit for the NESHAP required emission reduction in their SIP.

EPA evaluation: This revision makes the definition of Surplus consistent with CAA 

requirements that any emission reductions to be used as offsets, can not be required by any 

other CAA requirement (e.g., they must be surplus), including NSPS and NESHAP 

requirements. Therefore this revision is acceptable. 

Section 1 - Definitions

1. Repealed the remaining 33 terms of the obsolete definition section that has been replaced by 

Section 0 and requested that EPA rescind this rule from their portion of the Nevada SIP.

EPA evaluation: EPA evaluates this request below, in the section entitled Rule Rescission 

Requests.

Section 12.0 - Applicability, General Requirements and Transition Procedures

1. Added a clause to Section 12.0.1 that clarifies a new requirement of state law. The clause gives 

permitting jurisdiction to NDEP for sites that were formerly operated as coal fired facilities.

EPA evaluation: This provision is approvable because it implements state law, provides 

clarification of permit authority under the Nevada SIP and does not conflict with any CAA 

provision.

2. Added Section 12.0.6 to ensure that the Clean Air Act Section 110(a)(2)(F)(ii) and (iii) 

requirements are met.

EPA evaluation: Clean Air Act section 110(a)(2)(F)(ii) and (iii) require SIPs to include 

provisions that require periodic reports on the nature and amounts of emissions and emission 

related data from stationary sources and correlation of such reports by the local agency with 

any applicable emission limits or standards, and that such reports be made available for public 

inspection. Section 12.0.6(a) requires all sources operating under a permit to maintain records 

regarding the nature and amounts of emissions, as well as any other information necessary to 

determine if the source is in compliance with applicable emission limits. Paragraph (b) 

requires sources to report information as specified in their permits, or within 30 days of a 

written notice from the control officer. Paragraph (c) requires that the data obtained pursuant to 

Section 12.0.6 be correlated with application emission limits and be made available to the 
17

public during normal business hours. These provisions satisfy these CAA section 110(a)(2)(F)

requirements.4

Section 12.1 - Permit Requirements for Minor Sources

1. Made minor clarifying changes in Sections 12.1.0 and 12.1.1 that correct errors or remove 

nonessential references.

2. Corrected and clarified a reference to testing requirements in Section 12.1.4.1(m).

3. Corrected a subsection reference error in Section 12.1.6(b).

4. Inserted a clause in Section 12.1.6(d) that clarifies that emission increases for changes 

resulting in emissions of a new pollutant must be less than a significant amount, in order for the 

change to be made with prior notice.

EPA evaluation: These revisions are minor in nature and either correct errors or provide 

clarification. Therefore EPA has determined that each revision is acceptable. 

5. Consistent with the new provision in Section 12.0.4, added paragraph (w) to Section 12.1.4.1

(Permit Content) to require a condition which states that issuance of a permit does not affect 

the responsibilities of the permittee to comply with applicable provisions of the SIP. 

6. Deleted the language regarding the components of “enforceable as a practical matter” from 

Section 12.1.7, since that term was added to Section 0 identically to how it was listed in this 

section. 

EPA evaluation: Both of these revisions are conforming revisions to ensure consistency with 

revisions to Sections 0 and 12.0, which were already evaluated by EPA above, under the 

Section discussing revisions made to address previously identified deficiencies. We find that 

these conforming revisions are acceptable for the same reasons stated above.

7. In order to allow other emission units or activities to be considered Insignificant Activities on a 

case by case basis, the existing language of Section 12.5.2.5(c) was incorporated into Section 

12.1 as Section 12.1.2(c)(7)(H).

EPA evaluation: First EPA notes that it appears that the new provision should have been 

numbered as 12.1.2(d), as paragraph (c) is a list of exempt emission units and subparagraph (7) 

lists exempted temporary operations and experimental trials that meet specified criteria. EPA 

views this as a typographical error. The new language is a separate provision that allows the 

control officer to make a case-by-case decision as to whether an activity can be classified as an 

 4 EPA notes that in 2012 it partially disapproved Nevada’s infrastructure SIP (I-SIP) submittals for the 1997 ozone, 

1997 PM2.5, and 2006 PM2.5 NAAQS for several elements under section 110(a)(2) of the Clean Air Act. This included 

a partial disapproval for section 110(a)(2)(F)(iii), which requires the correlation of emissions reports and data 

collected under section 110(a)(2)(F)(ii) with any applicable emission limits or standards, and that such reports be 

made available for public inspection. See 77 FR 64737 (October 23, 2012). EPA finalized a similar disapproval with 

respect to Nevada’s I-SIP submittal for the 2008 Pb NAAQS in 2014. See 79 FR 15697 (March 21, 2014). If 

finalized, today’s action on Clark County rule section 12.0.6 would cure the partial disapproval from EPA’s 2012 and 

2014 I-SIP actions and turn off the two-year FIP clock for CAA section 110(a)(2)(F)(iii), which expires on November 

23, 2014. Id.
18

Insignificant Activity, provided emissions of one pollutant do not exceed two tons per year and 

all pollutants do not exceed 5 tpy. Because the stated emission thresholds are lower than the 

threshold for requiring a minor source permit (5 tpy or greater), EPA believes it is reasonable 

to allow the Control officer to determine whether such an activity is an “Insignificant Activity” 

for the purposes of Title V permit requirements (i.e., Section 12.4). Therefore we find this 

revision to be acceptable. However, the next time Clark County submits NSR revisions to EPA

it should amend this section to clarify that insignificant activities are their own subsection of 

exempt categories under section 12.1.2.

8. Added a 10 ton per year (tpy) public notice threshold for PM2.5 and H2S in Sections 12.1.5.3. 

Added a 10 ton per year (tpy) public notice threshold for PM2.5 and H2S in Sections 12.1.5.3. 

EPA evaluation: A minor source permit threshold of 5 tpy was added for PM2.5 in Section 

12.1.1(c), and thus a corresponding public notice threshold is also required. Section 12.1.1(c) 

already contained a minor source permit threshold of 1 tpy for H2S, but no public notice 

threshold was previously specified. This revision corrects that oversight. EPA finds that both 

of these new public notice thresholds are at acceptable levels for minor sources emitting these 

pollutants. 

Section 12.2 - Permit Requirements for Major Sources in Attainment Areas

1. Deleted language from the Section 12.2.2(c) definition of “Baseline Actual Emissions” that 

allowed emissions from startups and shutdowns associated with malfunctions to be excluded. 

Such exclusions are not permissible under federal law.

2. Deleted language from 12.2.2(nn) definition of “Projected Actual Emissions” that allowed 

emissions from startups and shutdowns associated with malfunctions to be excluded. 

EPA evaluation: These revisions make the definitions of “Baseline Actual Emissions” and 

“Projected Actual Emissions” consistent with the definitions of these terms in 40 CFR 

51.166(b), therefore EPA finds the revisions acceptable.

3. Added the air quality impact threshold for PM2.5 to the definition of “Baseline Area” in 

12.2.2(d), consistent with EPA promulgation of the threshold for PM2.5. 

4. Added the trigger date for PM2.5 to the definition of “Minor Source Baseline Date” in 

12.2.2(gg), consistent with EPA’s promulgation of the trigger date for PM2.5.

EPA evaluation: Both of these revisions incorporate new provisions from EPA’s PM2.5 rule

regarding increments (See 75 FR 64864, 10/20/10). The revisions are consistent with these 

new provisions; therefore EPA finds these revisions acceptable.

5. In both the definition of “Major Stationary Source” and “Significant”, revised the reference 

date for the term “subject to regulation” from July 20, 2011 to July 19, 2011. The effect of this 

revision is that the term “subject to regulation” will no longer exclude biomass sources. 

EPA evaluation: This revision makes the definitions of “Major Stationary Source” and 
19

“Significant” contained in Section 12.2 consistent with the July 2013 DC Circuit Court of 

Appeals ruling vacating the language found in the “subject to regulation” definition contained 

in 40 CFR 52.21 (b)(49) pertaining to the deferral of biomass emissions.5 It does this by 

referencing the definition of “subject to regulation” as July 19, 2011, the day prior to the 

addition of the biomass deferral language to 52.21. Therefore EPA finds these revisions 

acceptable.

6. Deleted listing number 27 from the 12.2.2(j) definition of “Categorical Stationary Source.” 

EPA evaluation: This revision removes redundancy while still keeping the definition of 

“Major Stationary Source” consistent with EPA’s definition of the same term, as found in 40 

CFR 51.166(b)(1). EPA notes that consistent with the provision regarding treatment of fugitive 

emissions in paragraph (iii) of EPA’s definition, the Section 12.2.2(ff) definition of Major 

stationary source includes the necessary language regarding other stationary source categories 

which, as of August 7, 1980, were being regulated under Section 111 or 112 of the CAA. 

Therefore, EPA finds this revision acceptable.

Section 12.3 - Permit Requirements for Major Sources in Nonattainment Areas

1. Deleted language from the 12.3.2(c) definition of “Baseline Actual Emissions” that allowed 

emissions from startup and shutdowns associated with malfunctions to be excluded. 

2. Deleted language from 12.3.2(hh) definition of “Projected Actual Emissions” that allowed 

emissions from startups and shutdowns associated with malfunctions to be excluded. 

EPA evaluation: These revisions make the definitions of “Baseline Actual Emissions” and 

“Projected Actual Emissions” consistent with the definitions of these terms in 40 CFR 

51.165(a), therefore EPA finds the revisions acceptable.

3. Added language to the Section 12.3.2(qq) definition of “Surplus” to clarify any emission 

reductions required by a NSPS or a NESHAP, are not creditable as offsets, unless the state has 

not taken credit for the NESHAP required emission reduction in their SIP.

EPA evaluation: This revision makes the definition of Surplus consistent with CAA 

requirements that any emission reductions to be used as offsets, cannot be required by any 

other CAA requirement (e.g., they must be surplus), including NSPS and NESHAP 

requirements. Therefore this revision is acceptable. 

4. Deleted listing number 27 from the 12.3.2(h) definition of “Categorical Stationary Source.”

EPA evaluation: This revision removes redundancy while still keeping the definition of 

“Major Stationary Source” consistent with EPA’s definition of the same term, as found in 40 

CFR 51.165(a)(1)(iv). EPA notes that consistent with the provision regarding treatment of 

fugitive emissions in paragraph (C) of EPA’s definition, the Section 12.3.2(y) definition of 

Major stationary source includes the necessary language regarding other stationary source 

 5 See Center for Biological Diversity v. EPA, 722 F.3d 401 (D.C. Circuit, 2013).
20

categories which, as of August 7, 1980, were being regulated under Section 111 or 112 of the 

CAA. Therefore, EPA finds this revision acceptable.

Section 12.4 Authority to Construct Application and Permit Requirements for Part 70 Sources

1. Added subparagraph (iii) to Section 12.4.3.1(a)(8) to clarify that when a project is major for 

one pollutant but not major for other pollutants (but still over the minor NSR threshold), then a 

control technology demonstration for RACT is required for the non-major pollutants. 

2. Revised Section 12.4.3.2(a)(1) to clarify that a RACT review is required when the emission 

increase is equal to or greater than the Minor NSR significant level, but less than the major 

source or major modification thresholds.

EPA evaluation: These revisions clarify RACT requirements for non-major sources. EPA 

finds these clarifications acceptable.

3. Added subparagraph (3) to Section 12.4.3.1(d) to require the Control Officer to determine that 

a new or modified source will meet all applicable requirements of Section 12 (entire permit 

program), prior to issuing an Authority to Construct or a Permit to Operate. 

EPA evaluation: This additional language is consistent with the requirements of 40 CFR 

5.160(b)(1), therefore EPA finds the revision acceptable.

4. Consistent with the new provision in Section 12.0.4, added subparagraph (D) to Section 

12.4.3.1(e)(10) (Permit Content) to require a condition which states that issuance of a permit 

does not affect the responsibilities of the permittee to comply with applicable provisions of the 

SIP. 

EPA evaluation: This is a conforming revision to ensure consistency with revisions to Sections 

0 and 12.0, which were already evaluated by EPA above, under the Section discussing 

revisions made to address previously identified deficiencies. We find that this conforming 

revision is acceptable for the same reasons stated above.

Rule Rescission Requests

1. DAQ has repealed Section 1 in its entirety and has requested that EPA rescind all of the 

remaining Section 1 definitions from the SIP. While EPA has previously approved versions of 

Section 0 – Definitions that replaced some of the SIP approved definitions contained in Section 

1 – Definitions, 33 terms still remain in the SIP approved version of Section 1. DAQ states that 

most of these terms have been incorporated into other sections of the DAQ’s Air Quality 

Regulations or are no longer useful. See Appendix A for more details. Therefore EPA proposes 

to rescind this rule as part of our rulemaking action to propose approval of the NSR SIP 

submittal.

2. DAQ has repealed Section 11 in its entirety and has requested that EPA rescind Section 11 

from the SIP as it is no longer needed. The provisions contained in Section 11- Ambient Air 

Quality Standards, have been replaced by a definition of the term National Ambient Air 
21

Quality Standards as contained in Section 0. The Section 0 definition for this term incorporates 

by reference all NAAQS in 40 CFR Part 50, including definitions, scope, reference conditions 

and appendices as of July 1 2012. EPA notes that it revised the NAAQS for PM2.5 in 2012, and 

minor NSR SIP revisions to implement this standard are due December 14, 2015. See 78 FR 

3086 (January 15, 2013) (final rule revising the annual PM2.5 standard). Although this NSR 

SIP submission is not yet due, we recommend that Clark County revise Section 0 to address the 

2012 PM2.5 NAAQS at its next opportunity. .EPA proposes to rescind Section 11 as part of our 

rulemaking action to propose approval of the NSR SIP submittal. 

3. DAQ has repealed Section 24 in its entirety and has requested that EPA rescind Section 24 

from the SIP as it is no longer needed. Section 24 contains 5 provisions. The first provision 

requires permitted sources to provide facilities for sampling and testing, upon request of the 

Control Officer. This provision already exists in Section 4 – Control Officer, which was SIP 

approved in 1982. See 47 FR 26386. The next three provisions require point sources to 

maintain records of the nature and amounts of emissions, summarize and report emission data 

as part of the registration renewal requirements, and maintain these records for two years. The 

fifth provision requires the collected emission data to be correlated with applicable emission 

limitations and be made available to the public. These last 4 provisions have been replaced by 

the provisions in Section 12.0.6. The new provisions are substantially equivalent to the 

existing Section 24 requirements, though they provide additional clarity and specificity 

regarding these requirements. Therefore EPA proposes to rescind this rule as part of our 

rulemaking action to propose approval of the NSR SIP submittal.

Section 110(l) of the Act

Section 110(l) states: “Each revision to an implementation plan submitted by a State under this 

chapter shall be adopted by such State after reasonable notice and public hearing. The 

Administrator shall not approve a revision of a plan if the revision would interfere with any 

applicable requirement concerning attainment and reasonable further progress (as defined in 

section 7501 of this title), or any other applicable requirement of this chapter.”

With respect to the procedural requirements of CAA section 110(l), based on our review of the 

public process documentation included in the April 1, 2014 submittal, we find that DAQ has 

provided sufficient evidence of public notice and opportunity for comment and public hearings 

prior to adoption and submittal of these rules to EPA. With respect to the substantive requirements 

of section 110(l), as discussed further below, our approval of the Clark County NSR SIP submittal 

(and replacement or supersession of the existing SIP NSR rules) would strengthen the applicable 

SIP in all respects. This action fixes the previously identified SIP disapproval issues and makes 

other minor revisions which do not impact the stringency of these rules. Our approval of the NSR 

SIP submittal would not interfere with any applicable requirement concerning attainment and 

reasonable further progress (RFP) or any other applicable requirement of the Act.
22

Conclusion. For the reasons set forth above, we can approve the submitted NSR program under 

section 110(l) of the Act.

Section 193 of the Act

Section 193 of the Act, which was added by the Clean Air Act Amendments of 1990, includes a 

savings clause which provides, in pertinent part: “No control requirement in effect, or required to 

be adopted by an order, settlement agreement, or plan in effect before November 15, 1990, in any 

area which is a nonattainment area for any air pollutant may be modified after November 15, 1990, 

in any manner unless the modification insures equivalent or greater emission reductions of such air 

pollutant.” 

EPA does not believe that NSR programs are control requirements for the purposes of section 193. 

See 70 FR 39413, at 39417 (July 8, 2005). However, we recognize that, on December 22, 2006, the 

D.C. Circuit issued a decision on South Coast Air Quality Management District v. EPA, No. 

14-1200, that may lead EPA to modify its interpretation of “control requirement” for the purposes 

of CAA section 193. Nonetheless, even if NSR were considered a “control requirement,” we find 

that the submitted NSR rules would insure equivalent or greater emission reductions compared to 

the SIP-approved NSR programs in the nonattainment areas in Clark County (for the PM10

NAAQS).

Conclusion. For the reasons set forth above, we can approve the submitted NSR program under 

section 193 of the Act.

Recommendations for Rule Revisions

EPA recommends that the next time Clark County submits NSR revisions it should amend section 

12.1.2 to clarify that insignificant activities are their own subsection of exempt categories under 

section 12.1.2, and not a subsection of 12.1.2(c) or 12.1.2.(c)(7). 

EPA’s Proposed Action

Pursuant to section 110(k)(3) of the Act, we are proposing to fully approve the submitted NSR 

rules. We are proposing to approve the submitted NSR rules based on our determination that the 

rules satisfy the applicable statutory and regulatory provisions governing regulation of stationary 

sources under CAA section 110(a)(2)(C), including the permitting requirements for major 

stationary sources in parts C and D of title I of the Act. In support of this proposed action, we have 

concluded that our approval of the submitted NSR rules (and supersession of the existing SIP NSR 

rules) would comply with section 110(l) of the Act because the revised program as a whole would 

not interfere with continued attainment of the NAAQS in Clark County. 
23

Attachments

1. Sections, 0, 12.0, 12.1, 12.2, 12.3, 12.4 and subsection 12.7.5 of Section 12.7

2. Section 1 Evaluation for Rescission

3. Sections 1, 11 and 24