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, Including M inor S ource, NSR and PSD programs

Roger Kohn Laura Yannayon

Jeanhee Hong

July 11 , 2012Table of Contents

Section Page

Introduction 1 Agency Name 1

NSR Program SIP Revision Submittal s 1 Background 3

Rule Summar ies 4 General Summary 4

Section 0 Definitions 5

Section 12.0 Applicability, General Requirements a nd Transition Procedures 5

Section 12.1 Permit Requirements f or Minor Sources 5

Section 12.2 Permit Requirements f or Major Sources i n Attainment Areas 8

Section 12.3 Permit Requirements f or Major Sources i n Nonattainment Areas 8

Section 12.4 Authority t o Construct Application and Permit Requirem ents f or Part 70 Sources 8

Rule Evaluation s 9 General Summary 9

Section 0 Definitions 9

Section 12.0 Applicability, General Requirements a nd Tr ansition Procedures 11

Section 12.1 Permit Requirements f or Minor Sources 1 1

Section 12.2 Permit Requirements f or Major Sources i n Attainment Areas 20

Section 12.3 Permit Requirements f or Major Sources i n Nonattainment Areas 3 0

Section 12.4 Authority t o Construct Application a nd Permit Requirements f or Part 70 Sources 4 1

Section 110(l) of the Act 4 6

Section 193 of the Act 5 0

Recommendations for Rule Revisions 5 1

EPA’s Proposed Action 5 31 

### Introduction

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

S ignificant D eterioration (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 NAA QS. Both parts C and D of the Act require pre

- construction permit programs for certain new or modified

sta tionary sources of pollutants. The requirements un der 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 poll utants 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 regulation s for new and

modified major stationary sources under parts C and D of title I

, the CAA re quires 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

.

Agency Name
The Department of Air Quality (DAQ or Clark) is the air pollution control district for Clark County, Nevada . This county department was previously named the Department of Air Quality

and Environmental Management , but o n March 6, 2012, the Clark County Board of County Commissioners approved the name change to the Department of Air Quality

.



### NSR Program SIP Revision Submittal s

The new and revised rules that are the subject of this Technical Support Document (TSD) were adopted by Clark on November 3, 2009, May 18, 2010, and March 6, 2012 and submitted to EPA via the Nevada Division of Environmental Protection (NDEP) by letters dated Februar y 11, 2010, September 1, 2010, and May 22, 2012, respectively. 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”) that NDEP has requested that EPA ap prove as revisions to the Clark County portion of the Nevada SIP are as follows : 1

1 DAQ also included a permitting regulation called “Section 12.11 (General Permits For Minor Stationary Sources)” as part of its NSR SIP Submittal but we are not proposing action on this regulation at this time.2 Section

Number Section Title Submittal Date (s)

0 Definitions 3/17/06, 2/11/10, 9/01/10

, 1/13/11 and 5/22/12

12.0 Applicability, General Requirements and

Transition Procedures 2/11/10

12.1 Permit Requirements for Minor Sources 2/11/10

12.2 Permit Requirements for Major Sources in

Attainment Areas 3/17/06, 9/01/10

, 1/13/11 and

5/22/12

12.3 Permit Requirements for Major Sources in

Nonattainment Areas Emission Offsets 3/17/06, 9 / 1 / 1 0

12.4 Authority to Construct Application and Permit Requirements For Part 70 Sources 9/01/10

These submitted versions of Sections 12.0, 12.1, 12.2, 12.3, and 12.4, collectively, establish a program for reviewing and permitting new or modified stationary sources in Clark County

. 2 This program relies upon certain definitions contained in submitted Section 0 as well as the definition of “ambient air quality standards” in SIP

- approved Section 11

. The se SIP revision submittal s are collectively referred to herein as the “ NSR SIP submittal ” or “ submitted NSR rules

. ” Although w e are proposing to act on only the most recently submitted version of each rule , which supersedes any previous submittals of that rule, we have reviewed materials provided with the previous

submittals for informational purposes

.

Consistent with Clark’s stated intent to have the submitted NSR rules replace the existing SIP NSR program in its entirety 3 , EPA’s approval of the submitted NSR ru les would have the effect of entirely superseding, or rescinding our prior approval of, each of the rules in the current

SIP

- approved NSR program, with the exception of two regulations: Nevada Administrative Code (NAC) 445B

- 2208 3 , which is implemented by t he State Environmental Commission (SEC) rather than Clark, and Section 11, which establishes Clark’s “ambient air quality standards.” Both NAC

445B

- 2208 3 and Section 11 remain in the applicable Nevada SIP and will not be affected by our proposed action. Th e SIP

- approved rules that would be superseded or rescinded, consistent with Clark’s request, are as follows :

2 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. We will evaluate Section 12.4 for compliance with the requirements of title V of th e Act and EPA’s implementing regulations in 40 CFR part 70 following receipt of an

official part 70 program submittal from Clark County containing this rule.

3 See Chapter 1, page 1

- 3 in “Proposed Revision To The Clark County Part Of The Nevada State Imple mentation Plan: Major Source New Source Review Program Rule Adoptions And Revisions,” August 31, 2010 (hereinafter “Major NSR SIP Submittal”).3 Section

Number Section Title SIP Approval Dates

0 Definitions 9/7/04

1 Definitions (33 specific terms) 4/14/81 & 6/21/82

12 Preconstruction Review For New Or Modified Stationary Sources 9/7/04

16 Operating Permits 6/18/82

58 Emission Reduction Credits 9/7/04

59 Emission Offsets 9/7/04

Background As explained above, the submitted NSR rules will, upon approval, entirely replace the SIP rules approved by EPA on September 7, 2004 (69 FR 54006, Sections 0, 12, 58, and 59), and June 18, 1982 (47 FR 26386, Section 16), with the exception of NAC 445B

- 2208 3 and Section 11, both of which remain in the SIP and are not affected by this action. For additional background information, the reader can consult the cited Federal Register notices. The current SIP

- approved NSR program in Section 12

– Preconstruction Rev iew for New or Modified Stationary Sources

and Section 16

– Operating Permits, contains requirements for both major and minor stationary sources, in attainment and nonattainment areas of the County. Section 0 and Section 1 contain definitions relating to n ew sources and modifications to existing sources of air pollution, and their regulation. Sections 58 and 59 contain requirements for the generation and use of emission

reduction credits.

Under the Act, as amended in 1977, EPA promulgated area designations within each State for all “criteria air pollutants” ( pollutants for which NAAQS had been established ). See 43 FR 8962,

9012

- 9013 (March 3, 1978). In the initial 1978 area designations, EPA designated all areas within Clark County, other than hydrographic area #212 (referred to herein as “Las Vegas Valley”), as

attainment or unclassifiable for all criteria air pollutants (i.e., oxidant, carbon monoxide (CO), total suspended particulate (TSP), sulfur dioxide (S O 2 ), and nitrogen dioxide (N O 2 )). EPA designated Las Vegas Valley as a nonattainment area for oxidant, CO, and TSP and as an

attainment area for SO 2 and N O 2

. Id. In 1979, EPA replaced the oxidant NAAQS with a NAAQS for ozone, but Las Vegas Valley retained its nonattainment designation upon transition to the new

standard. In 1986, EPA redesignated Las Vegas Valley from nonattainment to attainment for the ozone NAAQ S (see 51 FR 41788, November 19, 1986). In 1987, EPA revised the NAAQS for particulate matter (see 52 FR 24634), replacing TSP as the indicator for PM with a new indicator

called PM 10 that includes only those particles with an aerodynamic diameter less tha n or equal to a

nominal 10 micrometers , but Las Vegas Valley retained its nonattainment designation upon

transition to the new standard

.

The CAA was significantly amended again in 1990. These amendments required states with areas

that remained nonattainm ent to develop new attainment plans and revisions to existing Nonattainment NSR regulations. Las Vegas Valley was one of the areas that had not attained all of the NAAQS , and in 1991

, EPA reaffirmed the nonattainment designations for Las Vegas Valley

for C O and PM 10

. See 56 FR 56694, 56797

- 56799 (November 6, 1991). Las Vegas Valley remained designated attainment or unclassifiable for all other criteria pollutants, and t he rest of4 Clark County remained designated attainment or unclassifiable for all criteria pollutants

. In 1997

, EPA revised the NAAQS for ozone to replace the existing 1

- hour ozone standard of 0.12 parts per million (ppm) with an 8

- hour standard set of 0.08 ppm ( see 62 FR 33856, July 18, 1997) and promulgated a new NAAQS for particulate matter with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers (PM 2.5 ) ( see 62 FR 38652, July 18, 1997 ). 4 In 2004, EPA designated

certain portions of Clark County as nonattainment for the 1997 8

- hour ozone NAAQS ( 69 FR 23858, 23919 , April 30, 2004 ), and in 2005, EPA designated the entire State of Nevada as unclassifiable/ attainment for the 1997 PM 2.5 NAAQS ( s ee 70 FR 944, January 5, 2005). 40 CFR

81.329. In 2010 , EPA redesignated Las Vegas Valley to attainment for the CO NAAQS

. S ee 75 FR 59090 ( September 27, 2010)

. In 2011, EPA designated the entire State of Nevada as

unclassifiable/attainment for the 2008 L ead ( Pb ) NAAQS. See 76 FR 72095 ( November 22, 2011). In 2012, EPA designated the entire State of Nevada as unclassifiable/attai nment for the 2008

8

- hour ozone NAAQS. See 77 FR 30088 , 30134 (May 21, 2012).

Thus, Clark County is currently designated as attainment or unclassifiable for all NAAQS pollutants , with two exception s: certain portions of Clark County are designated nonattainment for

the 1997 8

- hour ozone NAAQS, and the Las Vegas Valley area within Clark County is designated

and classified as “serious” nonattainment for the PM 10 NAAQS

. 40 CFR 81.329 . EPA has determined, however, that both of these nonattai nment areas are attaining the standards. See 75 FR 45485 (August 3, 2010) (Determination of Attainment for PM 10 for the Las Vegas Valley Nonattainment Area, NV) and 76 FR 17343 (March 29, 2011) (Determination of Attainment for the Clark County 8

- Hour Ozone Nonattainment Area Thus, although both of these areas remain designated “nonattainment” for these pollutants u ntil such time as EPA redesignates them to “attainment” consistent with the requirements of CAA section 107(d)(3)(E), because of these determinations of attainment, the State of Nevada’s obligations under the CAA to submit

attainment demonstrations and oth er planning requirements related to attainment of these NAAQS are suspended for so long as the areas continue to attain both NAAQS. See id. EPA last approved revisions to Clark County’s SIP

- approved PSD, Nonattainment NSR, and minor NSR permit

programs on September 7, 2004. 69 FR 54006.



### Rule Summar ies

General S ummary Submitted Section s 0, 12.0, 12.1, 12.2, 12.3, and 12.4 represent a comprehensive revision to Clark County's stationary source permitting program s and are intended to satisfy the requirements of section 110(a)(2)(C) and parts C and D of title I of the Act

. Section 0 contains definitions of terms relating to new sources and modifications to existing sources of air po llution, and their regulation.

Section 0 also contains numerous definitions used in prohibitory local rul es not directly related to

NSR. W ith respect to Section 0, our proposed action applies to the entire submitted rule, not just

those defini tions directly related to NSR. Section 12.0 defines how the transition from the current

SIP r ules to the new ly adopted rules will occur and also identifie s general requirements for sources

4 EPA has also established increments for PM 2.5 and established a July 20, 2012 deadline for states to submit PSD SIP revisions that incorporate the se PM 2.5 increments or alternative measures providing an equivalent level of protection

. See 75 FR 64864 (October 20, 2010).5 that may be ex empt from permit requirements. Section 12.1 contains the requirements for Clark to issue federally enforce able permits to “ minor sources ” as defin ed in Section 12.1.1(c)

. Sections 12.2 and 12.3 contain the requirements for Clark to issue federally enforceable permits to major sources in attainment areas (12.2) and nonattainment are as (12.3) within Clark County. These requirements include those relat ed to applicability, control standards ( i.e, Lowest Achievable Emission Rate, or LAER ) and emission offsets in nonattainment areas, and control standards (i.e., Best Available Control Technology, or BACT ) and air quality impact analyse s in attainment areas

. Sections 12.2 and 12.3 also contain procedural requirements for permit issuance. Section 12.4

contains additional procedural requirements for permit issuance, including application and permit content requirements for stationary sources subject to title V of the CA A (federal operating permits).

We provide more detailed evaluations of each of these rules in the “ Rule Evaluation s ” section of

this Technical Support Document ( TSD )

.

Section 0

– D efinitions This existing rule was significantly revised by the Clark County Board of County Commissioners’ rulemaking action of November 3, 2009 and most recently revised on March 6, 2012

. Section 0

consists of definitions for terms relating to new sources and modifications to existing sources of air pollution. Secti on 0 also contains numerous definitions used in prohibitory local rules not directly

related to new source review. Some of these prohibitory rules are already approved into the SIP.

The revision s eliminated terms that are no longer used, updated terms to r eflect their current meanings and added terms that support new rules and rule revisions.

The definitions in Section 0 generally apply to multiple regulations, while the definitions provided

in each Section 12 rule only apply to that particular rule or to the specified sub section of that rule

. Clark has relocated s everal d efinitions that are only used in a specific rule , such as Section 12.2 or

Section 12.3, to those specific rules

. Terms that are not defined in a Section 12 rule generally have the meaning provided in Section 0 , except as noted otherwise

.

Section 12.0

– A pplicability, General Requirements a nd Transition Procedures

This is a new rule that generally explains the applicability of the permitting rules to major and minor stationary sources (Sections 12.1

- 12.4 and 12.11), and is designed to help a reader quickly understand which part(s) of Section 12 may apply to a particular facility

. Sect ion 12.0 also explains how the transition from the current SIP rules to the new rules will occur and identifies general requirements applicable to sources that may be exempt from permit requirements.

Section 12.1

– Permit Requirements for Minor Sources This is a new rule intended to implement Clark ’s minor source permit program, as required by 40

CFR sections 51. 160

– 51. 164. This program applies , with limited exceptions, to any existing, new or modified stationary source that ha s a “ potential to emit ” a ny of the following seven pollutants

above certain “de minimis” levels but is not a “ major stationary source ” or “major modification” as defined in 40 CFR sections 51.165 or 51.166 : PM 10 , CO, VOC, NO

x , SO 2 , Pb, or H 2 S

.6 Section 12.1 establishes specific application and permit requirements for all existing, new and

modified minor sources. The rule includes section s for applicability , definitions, exemptions, and permit application and permit content requirements, as well as permit processing requirements

a pplicable to Clark , including public notice requirements. Each rule section is discussed in further

detail below. EPA notes that Clark has chosen to include many Title V permit related provisions in its new minor source program . Although most minor sources are not subject to the CAA’s Title V operating permits program
, we expect that many of the Title V

- derived provisions in Clark’s minor NSR program will clarify its requirements and strengthen its enforceability.

Subsection 12.1.0 ( Applicability ) , states that the rule applies to any stationary source with a potential to emit (PTE) a regulated air pollutant equal to or greater than the de minimis PTE thresholds specified in subsection 12.1.1(c) for minor sources, but less than the major source thresholds specified in Section 12.2, “ Permit Requirements For Major Sources in Attainment Areas (Prevention Of Significant Deterioration), ” and Section 12.3, “ Permit Requirements For Major Sources in Nonattainment Areas (New So urce Review)

. ”

Subsection 12.1.1 ( Definitions )

, defines seven specific terms used in S ections 12.0, 12.1, 12.4, 12.5, and 12.11 , and explains how any term s not defined within the se rule s should be defined

.

Subsection 12.1.2 ( Emission Units and Activities Exempt from Permit Requirements ) , provides a

list (in paragraph (c)) of equipment and activities that are exempt from the permitting requirement

of Section 12.1 , and uses a cross

- reference (in paragraph (a)) to exempt emission units deemed insig nificant under Section 12.5 ( Part 70 Operating Permit Requirements ) . This subsection also provides that such exempt equipment or activities must be listed in the application and permit, that such equipment or activities remain subject to other applicable r equirements, and that the potential

to emit of such exempt units or activities shall be considered when determining the PTE of a stationary source.

P aragraph (c) of subsection 12.1.2 exempts specific types of emission units and activities from the permitting requirements of Section 12.1

– for example , laboratory equipment used for specific purposes, hot water production not used for any industrial process, road maintenance activities, and several types of temporary construction activities, such as padding machines, debris grinders and trenching machines if being used under the conditions of a Dust Control Permit issued pursuant to Section 94. It also exempts temporary operations and experimental trials involving the construction, reconstruc tion or modification of a source if the project meets the criteria listed in paragraph (c)(7) , as applicable . These criteria provide , among other things, that a temporary project cannot increase the PTE of the affected stationary source above the major sou rce thresholds or by more than 15 tons, and the duration of the temporary operation or experimental

trial must be less than 30 days. Additional restrictions are imposed on soil or water remediation projects in paragraph (c)(7)(D). Paragraph (c)(7)(E) provi des that if the project would otherwise require a permit, then written notification must be provided to the Control Officer at least 7 days before it begins operation which describes the purpose of the project, why it qualifies for the exemption and antici pated dates of operation. Paragraph (c)(7)(F) provides that if the project would otherwise require a permit, then written notification must be provided to the Control Officer7 within 7 days after concluding the project which provides the actual date the pro ject started and ended, and the actual emissions from the project. Finally, paragraph (c)(7)(G) states that exemptions provided under paragraph (c)(7) do not apply if the compan y’s normal course of business involves temporary and experimental operations.

Subsection 12.1.3 ( Permit Application )

, establishes requirements for permit applications, such as the duty to apply and obtain a minor source permit, the timing of required applications, the required contents of a complete application, requirements for obtaining a permit application shield, and the duty to supplement or correct a submitted application as appropriate

. These procedures and requirements are necessary to ensure implementation of a n enforceable permit

program. Importantly, s ubsection 12.1.3 p rohibits any person from commencing construction of, operating, or making a modification to a minor source except in compliance with a minor source permit authorizing such construction, operation, or modification. See Section 12.1, s ubsection

12.1.3.1.

Subsection 12.1.4 ( Permit Content ) , specifies the types of terms and conditions that Clark minor source permits must have. These include the identification of all applicable requirements, emission limits that ensure the protection of the NAAQS, and monitor ing, testing, reporting, and recordkeeping requirements to verify compliance. This subsection also requires that all permits contain a statement that commencement of operation constitutes the permittee’s acknowledgment that it is responsible for ensuring t hat the source’s emission units and emission control equipment have been constructed and will be operated in compliance with all applicable requirements.

Subsection 12.1.5 ( Permit Application Processing Procedures ) , specifies the conditions that must

be m et before Clark may issue a final permit, including receipt of a complete application, public

notice procedures where required, and Clark ’s determination that the source or emission units will not interfere with attainment and maintenance of the NAAQS. Thi s subsection also establishes deadlines for the issuance or denial of a permit, which range from 75 to 150 days after the application is determined to be complete , depending on whether the action is for an existing or new minor source, a significant permit revision, or a permit renewal. The rule also addresses public notice requirements in this subsection, specifying which permitting actions require public notice

based on emission thresholds and the location of the source.

Subsection 12.1.6 ( Revisions to an Existing Minor Source Permit ) , establishes the criteria for determining what types of changes at a minor source require a significant permit revision and what types of changes may be allowed through other processes

. “ Significant permit revisions ” must

u ndergo public participation procedures as specified in subsection 12.1.5.3

. For “ minor permit

revisions

, ” public notice is not required and the proposed modification may be implemented seven days after an application is submitted , unless Clark objects within this 7

- day period

. Clark is required to take a final action on a minor permit revision within 30 days of receipt. This subsection

also establishes criteria for administrative permit revisions, changes tha t can be made with prior

notice and changes that can be made with on

- site logging.8 Subsection 12.1.7 ( Permits Containing Voluntarily Accepted Emission Limitations and

Standards ) , contains the permit content requirements for sources that seek to limit their potential to emit in order to avoid being subject to requirements that would otherwise apply, including NSR and title V permitting requirements and Reasonably Available Control Technology ( RACT ) requirements

.

Sec tion 12.2

– Permit Requirements f or Major Sources i n Attainment Areas

This submittal contains Clark County’s regulations to implement the requirements of the Prevention of Significant Deterioration (PSD) program in part C, title I of the Act and EPA’s implementing regulations in 40 CFR 51.160

- 164 and 51.166. This program applies to large new

and modified sources of criteria pollutants for which Clark County has been designated as

attainment or unclassifiable and certain other (non

- criteria) pollutants subjec t to regulation under

the CAA

.

Section 12.3

– Permit Requirements f or Major Sources i n Nonattainment Areas

This submittal contains Clark County’s regulations to implement the requirements of the

Non attainment New Source Review (NSR) program in part D, title I of the Act and EPA’s implementing regulations in 40 CFR 51.160 through 51.165. This program applies to large new

and modified sources of criteria pollutants for which Clark County (or a portion thereof) has bee n designated as nonattainment.

Section 12.4

– Authority t o Construct Application a nd Permit Requirements f or Part 70 Sources Clark currently implements a combined NSR and Title V permit program. This means that any source required to obtain a PSD/NSR permit under Sections 12.2 or 12.3 must also comply simultaneously with the applicable part 70 operating permit requirements in Section 12.4. Section 12.4 provides the administrative procedures for sources to apply for and obtain an Authority to Construct Permit (ATC Permit), consistent with the applicable requirements of Sections 12.2 or

12.3.

Subsection 12.4.1 ( Authority to Construct Permit Required; Duration )

, specifies the timing requirements for ATC Permit s, such as requiring a source to obtain such permit prior to actual construction, the provisions u nder which the permit remains in effect, and when a Part 70 permit must also be obtained prior to commencing operation

.

Subsection 12. 4

. 2 ( Definitions )

, contains definitions for terms used in this rule, and specifies the order in which other regulations may be referenced to define other terms used in the rule.

Subsection 12.4.3 ( Authority to Construct Permit for Part 70 Sources )

, contains the required procedures for obtaining an ATC Permit. Paragraph 12.4.3.1 contains the application submission, processing and issu ance requirements which apply if the project is subject to the requirements of Section 12.2 or 12.3. This includes the general application requirements, as well as the specific application requirements for sources subject to th o se S ectio ns. In subparagraph (d)

, the rule provides the application processing procedures to be followed by Clark , such as the time period allowed for determining an application is complete. Subparagraph (e) lists all of the required9 content s of an ATC Permit. Simi larly, Paragraph 12.4.3.2 contains the application submission, processing and issuance requirements which apply if the project is not subject to the requirements of Section 12.2, 12.3 or s ubsection 12.4.3.3 (requirement s applicable to MACT sources). Because

these projects are not subject to the control requirements of Section 12.2 or 12.3 (i.e., BACT or LAER) , this paragraph specifies requirements for implementation of Reasonably Available Control Technology (RACT). Paragraph 12.4.3.3 specifies additi onal application requirements for a project subject to any of the construction or reconstruction provisions of CA A s ection 112(d), (f) or (h). Paragraph 12.4.3.4 contains the required procedures for revising an ATC Permit once it has been issued. Finally, Paragraph 12.4.3.5 identifies the administrative procedures for revising permit conditions subject to the CAA Title I V Acid Rain program.



### Rule Evaluation s

General S ummary For this Technical Support Document (TSD), EPA reviewed the submitted NSR rules for compliance with the CAA requirements for SIPs in general as set forth in CAA section 110(a)(2)

, the requirements for stationary source preconstruction permitting programs in 40 CFR part 51, subpart I ( Review of New Sources and Modifications )

, and the requirement s related to SIP

revisions in CAA section s 110(l) and 193. EPA also relied on the following materials in the review

of Clark ’s overall NSR regulations: General Preamble for the Implementation of Title I of the

Clean Air Act Amendments of 19 90 (see 57 FR 13498, April 16, 1992), EPA’s Emission Offset Interpretive Ruling (40 CFR part 51, appendix S), and EPA’s policy document entitled, “Improving Air Quality with Economic Incentive Programs,” that was published in January 2001.

EPA has condensed the approval criteria contained in these various materials in this TSD, which describes reasons for our action on the NSR SIP submittal for Clark County.

Section 0

– Definitions Clark County’s revisions to Section 0 added new terms that support the new Section 12 series of rules, updated terms to reflect their current meanings, and eliminated terms that are no longer used. These revisions represent an overall improvement to the current SIP rule by updating the terms and

definitions used. The revi sions do not directly affect emissions but clarify the application of other Clark County air pollution rules. EPA has reviewed each of the new and revised definitions and has determined that they are clear and consistent with the use of terms in other Clar k rules and

consistent with EPA definitions , where applicable

. We identify b elow the Section 0 definitions

that Clark County has added, revised or deleted since EPA last approved Section 0 into the Clark County portion of the Nevada SIP (69 FR 54006, Septe mber 7, 2004)

.

New definitions added: Air Contaminants, Air Quality Planning Region, Commence Operation, Complete, Date of Submittal, Emission Limit or Emission Limitation, Excess Emissions, Good Engineering Practice (GEP), Insignificant Activities and Emissions, Operation and Maintenance Pla n, PM 2.5 , Reasonably Available Control Technology (RACT), Reconstruction or Reconstruct, and Shutdown.10 Definitions revised: Administrator, Affected Source, Affected State(s), Airplane Refueling Area, Air Quality Area, Allowable Emissions, Applicable Requ irement, Best Management Practice, British Thermal Unit, Building, Structure, Facility, or Installation, Building Vent, Commence, Control Officer, Construction, Disturbed Surface Area, Dust Palliative, Dust Suppressant, Emergency, Emission or Emit, Emissio ns Unit, EPA, Ethanol, Existing Emissions Unit, Existing Stationary Source, Federally Enforceable, Fuel, Fuel Oil, Fugitive Dust, Gasoline, Gasoline Dispensing Facility, Hazardous Air Pollutant, Hydrographic Basin Areas or Hydrographic Areas, Incinerator, Leak Free, Methyl Tertiary Butyl Ether, Motocross Race Course, Natural Cover, Nonattainment Area, Non

- metallic Mineral, Non

- Metallic Mineral Processing Plant, Non

- Road Easement, Opacity, Opera Areas And Vacant Lots, Owner and/or Operator, Oxygenated Gasoli ne, Part 70 Operating Permit, Part 70 Source, Particulate Matter (PM), Pave or Paved, Person, PM 10 , Permanent, Potential to Emit, Prime Coat, Public Road, Regulated Air Pollutant(s), Secondary Emissions, Single Coat, Stack, Stationary Source, Surplus, Top Off, Topsoil, Vapor Control System, Vapor Tight, and Volatile Organic Compound (VOCs).

Definitions deleted: Aggrieved Party, Asbestos, Banking, Baseline, Confidential Information, Designated Representative, Diesel Fuel, Easement, Easement Holder, Emergency Standby Generator, Emergency Standby Diesel Powered Generator, Exempt Stationary Source, Freeboard Ratio, Fugitive Gas, Garbage, Gas, Gasoline Station, General Permit, Hearing Board, Hearing Officer, Highly Volatile Solvent, Large Appliances, Low Organic Solvent Coating, Major Part 70 Source, Malfunction, Management Area, Maximum Achievable Control Technology (MACT), Maximum Achievable Control Technology (MACT) Floor, Modification, Modified Emission Unit, MTBE, Multiple Chamber Incinerator, Offset, Permit for Construction Activities, PM 10 Nonattainment Area, Process Equipment, Proposed Permit, Reconstruction, R egistry or Bank, Representative of Alleged Violator, Section 58 ERC Bank Certificate, Significant Source, Temporary Stationary Source, Total Suspended Particulate (TSP), Toxic Chemical Substance (TCS), Trench, Upset/Breakdown, Vacant Lot, Various Locations Activity, and

Waste.

Definitions moved to Section 12.2 and revised : Baseline Area, Baseline Emissions, Baseline Concentration, Baseline Area, Baseline Concentration, Baseline Area, Baseline Concentration, Begin Actual Construction, Best Available Control Technology, Major Modification, Major Stationary Source, Baseline A rea, Baseline Concentration, Net Emissions Increase, Non Major Source Baseline Date (New term is “minor source baseline date”), Prevention of Significant Deterioration (PSD) Program, PSD, Trigger Date.

Definitions moved to Section 12.3 and revised : Basel ine Emissions, Begin Actual Construction, Best Available Control Technology, Emission Reduction Credit (ERC), Lowest Achievable Emission Rate, Major Modification, Major Stationary Source, Net

Emissions Increase.

Title V related definitions moved to Sectio n 12.5 and revised: Operating Permit, Part11 70 Permit Modification, Part 70 Permit Revision, Part 70 Program, Responsible Official, Section 502(B)(10) Changes.

Section 12.0

– Applicability, General Requirements and Transition Procedures

This rule summariz es the applicability provisions of the Section 12 permitting programs as Clark makes the transition from the old to the new permitting rules. Section 12.0 does not in itself establish any substantive permitting requirements but instead establishes timefram es for the applicability of the new rules to stationary sources that had been subject to Clark’s previous permitting rules. The rule is designed to ensure a smooth transition between the old and new permitting programs to be carried out under these rules. This rule is clear and enforceable, and appropriate for approval into the SIP.

It should be noted that, pursuant to State law, the State of Nevada, not a local air district, has jurisdiction over plants which generate electricity by using steam produced b y the burning of fossil fuel within the State of Nevada. The applicable State law, now codified in Nevada Revised Statutes (NRS) 445B.500, was approved by EPA in 1980 as NRS 445.546(4). See 45 FR 46384 (July 10, 1980) (codified at 40 CFR 52.1470(b)(14)(ii) ). Thus, the State, not Clark County, has jurisdiction over such plants that are located or that will be constructed within Clark County. The Section 12 permit programs therefore apply to any stationary source located in Clark County, except for a plant wh ich generates electricity by using steam produced by the burning of fossil fuel, which is subject to NDEP’s jurisdiction. See Section 12.0, subsection 12.0.1(a).

Section 12.1

– Permit R equirements for Minor Sources

We reviewed this rule for compliance wit h EPA’s regulations in 40 CFR 51, subpart I, excluding 40 CFR 51.165 and 51.166, which apply only to new major sources and major modifications under parts C and D of title I of the CAA.

1. 40 CFR 51.160

– Legally enforceable procedures

(a) Each plan mus t set forth legally enforceable procedures that enable the State or local agency to determine whether the construction or modification of a facility, building, structure or installation or combination of these will result in (1) a violation of applicable

p ortions of the control strategy; or (2) interference with attainment or maintenance of a national standard in the state in which the proposed source (or modification) is located or in a neighboring State.

Discussion: S ubsections 12.1.3.2 and 12.1.3.3 establish requirements for sources to submit timely and complete permit application s

. S ubsection 12.1.3.6 requires that each permit application identify, among other things, the potential to emit (PTE) of all regulated air pollutants emitted from each

emis sion unit and provide detailed information about equipment and fuel s used

. S ubsection 12.1.4 requires that each minor source permit issued by Clar k include emission limitations that ensure that “[t]he ambient air quality standards will be attained or maint ained” (12.1.4.1(c)) and emission

limitations and standards (including operational requirements) necessary to “ensure that any ambient air increment as prescribed by subsection 12.2.3 is not exceeded” (12.1.4.1(f))

. Finally,12 s

ubsection 12.1.5.1 requires that Clark determine, as a precondition to permit issuance, that the permit terms “provi d e for compliance with all applicable requirements

. ” See Clark County DAQ, Technical Support Document, Sections 0 & 12, “Chapter 3: Technical Support Document for Sections 0, 12.0, 12.1, and 12.11,” at 3

- 20, 3

- 21 (October 21, 2009) (hereinafter “Minor NSR TSD”)

. 5 These provisions are legally enforceable and generally provide information specific enough to enable

Clark to determine whether a new or modified minor source would violate any applicable portion of the control strategy or interfere with attainment or maintenance of the NAAQS , as required by 40
CFR 51.160 (a)

. These provisions are acceptable to satisfy this requirement, with one significant exception . The term “ambient air quality standards” in subsection 12.1.4.1(c) appears to be in reference to Clark’s ambient air quality standards in Section 11, which are not entirely consistent with the NAAQS. Section 11, which EPA approved into the SIP on Septemb er 7, 2004 (69 FR 54006), defines “ambient air quality standards” and related provisions consistent with most of the NAAQS but

does not include the 2006 24

- hour PM 2.5 NAAQS (35 ug/m3) or the 2008 Lead (Pb) NAAQS (15 ug/m3, rolling 3

- month average). See 40 CFR 50.13 and 50.16. We propose to disapprove Section 12.1 to the extent it does not address these revised NAAQS. This limited disapproval, if finalized, would require Clark to revise Section 12.1 to address the requirements of 40 CFR 51.160

- 164 with

respe ct to EPA’s revised NAAQS for PM 2.5 and Lead.

EPA also revised the NAAQS for NO 2 and SO 2 in 2010, and minor NSR SIP revisions to implement these standards are due January 22, 2013 and June 2, 2013, respectively. See 75 FR 6474 (February 9, 2010) (final r ule establishing new 1

- hour standard for NO 2 ) and 75 FR 35520 (June 22, 2010) (final rule establishing new 1

- hour standard for SO 2 ). Although these NSR SIP submissions are not yet due, we recommend that Clark include provisions necessary to implement these new NAAQS in a revised SIP submission in response to our proposed limited approval and limited disapproval of Section 12.1.

We note that it is not entirely clear how Clark would establish emission limitations meeting the requirements of subsection 12.1.4(c) and 12.1.4(f) in the absence of any requirement in Section 12.1 for permit applicants to evaluate air quality impacts (thr ough air quality modeling or otherwise), and we encourage Clark to reevaluate these provisions at its earliest opportunity to address this issue. According to 2003

- 2006 emissions inventory information submitted by Clark County, emissions from

minor station ary sources in Clark County comprise, for most NAAQS pollutants, less than 3% of total inventoried emissions in the county, and roughly 19% of total inventoried VOC emissions in the county are attributed to minor source emissions. See Appendix D

– Emission Inventory Tables, in “Proposed Revision To The Clark County Part Of The Nevada State Implementation Plan: Minor Source New Source Review Program Rule Adoptions And Revisions,” January 29, 2009 (“Minor NSR SIP Submittal”) ; see also Memorandum to File dated July 10, 2012, Laura Yannayon, EPA Region 9, RE: “EPA evaluation of Clark County minor source emissions,” including attachment. Clark County’s supporting documentation states that neither of the attainment/maintenance

demonstrations for CO or PM 10 for the area relied on any permit requirements for CO or PM 10 emissions because of the de minimis impact of stationary source emissions on ambient levels of

5 Included as Chapter 3 in “Proposed Revision To The Clark County Part Of The Nevada State I mplementation Plan: Minor Source New Source Review Program Rule Adoptions And Revisions,” January 29, 2009 (hereinafter “Minor NSR SIP Submittal”).13 these pollutants, and that none of the control strategies in the Nevada SIP rely upon regulation of

new mi nor sources or modifications to existing minor sources. See Minor NSR TSD at 3

- 20, 3

- 21,

3

- 26 and 3

- 27. Given Clark’s documentation of the insignificant portion of total inventoried emissions attributed to minor sources in Clark County, we believe it is re asonable for Clark to implement a minor NSR program that does not require individual source impacts analyses.

(b) Such procedures must include means by which the State or local agency responsible for

final decision

- making on the application for approval to construct or modify will prevent such construction or modification if (1) it will result in a violation of applicable portions of the control strategy; or (2) it will interfere with the attainment or maintenance of a national

standard.

Discussion : Subs ection 12.1.3.1 prohibits any person from commencing construction of, operating, or making a modification to a minor source “ except in compliance with a minor source permit that authorizes such construction, operation, or modification.” Subsection 12.1.5.1 (a) states that a new minor source permit, significant permit revision or permit renewal may be issued only if certain conditions are met, including a requirement that the Control Officer determine 1) that the permit conditions provide for compliance with all applicable requirements (including the SIP) and 2) that the

source will not interfere with attainment and maintenance of the NAAQS. These provisions are acceptable to satisfy this requirement

.

(c) The procedures must provide for the submission, by the owner of operator of the building, facility, structure, or installation to be constructed or modified, of such information on (1) the nature and amounts of emissions to be emitted by it or emitted by associated mobile sources; (2) the location, design, co nstruction, and operation of such facility, building, structure, or installation as may be necessary to permit the State or local agency to make the determination referred to in paragraph (a) of this section.

Discussion : Subsection 12.1.3.6

– Application Contents, specifies the required application submittal information. The information specified is sufficient for Clark to make the determinations referred to in 40 CFR 51.160(a). This provision is generally acceptable to satisfy this requirement. However, w e cannot approve subsection 12.1.3.6(a)(5), which purports to limit Federal enforcement authority by provid ing that an applicant may state that “ it wants the entire permit, or specifically identified permit conditions or applicable requirements, to be federally enforceable .” Although title V operating permits issued under an approved part 70 program may, in some cases, distinguish f ederally

- enforceable permit provisions from State

- only provisions, this is not permissible for minor NSR purposes

, as all

c

onditions of a permit issued pursuant to a SIP

- approved permit program are f ederally enforceable

. See CAA 113, 304; see also 40 CFR 52.23

. We therefore propose to disapprove this provision. This limited disapproval, if finalized, would require Clark to rev ise subsection 12.1.3.6 to delete the language in subparagraph (a)(5) regarding f ederal enforceability. As a general matter, we note that any statement contained in a permit application regarding f ederal enforceability has no effect

whatsoever on EPA’s or citizen s’ enforcement authorities under sections 113 and 304 of the Act.

(d) The procedures must provide that approval of any construction or modification must not affect the responsibility on the owner or operator to comply with applicable portions of14 th e control strategy.

Discussion : Section 12.1 does not contain a provision to satisfy this requirement. EPA is identifying

the lack of such a provision as a deficiency and proposing to disapprove Section 12.1 with respect to this requirement

. This limited disapproval, if finalized, would require Clark to revise Section 12.1 to include a provision meeting the requirement in 40 CFR 51.160(d) and to submit the revised rule to EPA for approval into the Clark County portion of the Nevada SIP

.

(e) The procedures must identify types and sizes of facilities, buildings, structures, or installations which will be subject to review under this section. The plan must discuss the basis for determining which facilities will be subject to review.

Discussion : Section 12.1 applies to “any stationary source located in Clark County that has the potential to emit (PTE) a regulated air pollutant [ in amounts ] equal to or greater than the thresholds

listed in subsection 12.1.1(c ), but less than the major source thres holds listed in 12.2 .2.1(ff) or 12.3 .2(y)

. ” Subsection 12.1.0; see also subsection 12.1.1(a) (defining “exempt stationary source”).

Sub s

ection 12.1 .1 defines “minor source” as a source not required to obtain a permit pursuant to

S ection 12.4, s ubsection 12.4.3 or Part 70 and that ha s a potential to emit equal to o r greater than specified thresholds for six criteria pollutants 6 (pollutants for which EPA has established national ambient air quality standards) and H 2 S. These thresholds range from 0.3 tons pe r year (tpy) for lead, to 25 tpy for CO. See subsection 12.1.1 ( c)

. S e ction 12.1 identifies specific types of emission units and activities that are exempt from the requirement to obtain a Section 12 permit (subject to specified conditions)

, such as medical or veterinary laboratories devoted to experimental study, teaching, or the testing and analysis of substances not sold or distributed commercially. See subsection s 12.1.2 (a) and (c). E mission units or activities listed in subsection 12.5.2.5 are a lso covered by this

exemp tion

. See subsection 12.1.2(a). Clark established these emission thresholds and “categorical exemptions” by balancing the need to ensure that facilities that impact air quality have permits against the need to exempt sources that have insignificant or no impacts on air quality. S ee Minor

NSR TSD at 3

- 3. The actual number of sources that currently hold permits and that would no longer need individual permits under the revised Section 12.1 requirements is approximately 190 sources or less than one percent of total sources, and according to Clark, these are extremely small sources with very little or no impact on ambient air quality. See id. at 3

- 4; see also Memorandum to File dated July 10, 2012, Laura Yannayon, EPA Regi on 9, RE: “Number of minor NSR permitted sources.”

Subsection 12.1.6 contains the requirements for revisions to existing minor source permits and identifies the types of changes subject to “ Significant, ” “ Minor ” or “ Administrative ” p ermit r evisions, as

we ll as changes that can be made with “ Prior Notice ” or “ On

- site Logging. ” Importantly, a “Significant

Permit Revision” includes any modification that increases the source’s potential to emit (PTE) a regulated air pollutant by an amount equal to or exceeding the “significan t ” levels in subsection 12.1.1(g)

, and may not be made without a permit issued pursuant to the procedures in subs ection s 12.1 .3 and 12.1.5

. See subsection 12.1.6(a). The “significan t ” levels in subsection 12.1.1(g) range

from 0.6 tpy for lead (Pb) to 40 tpy for sulfur dioxide ( SO 2 ). O ther types of minor source permit

revisions in subsections 12.1.6(b), (c), (d), and (e) ( i.e., for “minor permit revisions,” “administrative

6 As noted further below, Section 12.1 does not apply to minor sources of PM 2.5

.15 permit revisions,” changes that can be made with “prior notice,” and changes that can be made with

“on

- site logging” ) are not subject to public process and generally may proceed unless Clark objects within a specified number of days after the permittee has provided some form of notice

.

EPA regulat ions in 40 CFR 51.160(e) allow s tate NSR programs to exclude new minor sources and minor modifications from the NSR program so long as such sources and modifications are not environmentally significant, consisten t with the de minimis exemption criteria set forth in Ala. Power

Co. v. Costle , 636 F.2d 323, at 360

- 361 (D.C. Cir. 1979). 7 In this instance, we believe that the

emissions

- based thresholds and categorical exemptions in subsections 12.1.1 (c) and 12.1.2 and the

emissions

- based thresholds for “significant” permit revisions in subsection 12.1. 1 ( g

) generally represent well

- defined objective criteria and are reasonably calculated to exclude from review only less environmentally significant so urces and modifi cations , based on Clark’s evaluation of the insignificant portion of total stationary source emissions attributed to minor sources . These provisions are acceptable , with one exception: the exemption in subsection 12.1.2(a) for emission

units or activities listed in subsection 12.5.2.5 is not approvable because Section 12.5 is n either approved into the SIP nor included in the NSR SIP submittal , and we therefore have no basis for concluding that the exemption is appropriate for minor NSR purposes

. We propose to disapprove this provision. This limited disapproval, if finalized, would require Clark to either revise subsection 12.1.2(a) t o remove the exemption for emission units or activities identified in Section 12.5

, or to
submit the relevant portions of Secti on 12.5 for approval into the Clark County portion of the Nevada

SIP.

With respect to the additional provisions for minor source permit revisions in subsection s 12.1.6(b) through (e) ( i.e., for “minor permit revisions,” “administrative permit revisions,” changes that can be made with “prior notice,” and changes that can be made with “on

- site logging”), we find these provisions to be acceptable to the extent that they apply only to physical or operational changes at a

minor source that do not increase the source’s PTE by “significant” amounts. See, e.g., subsections 12.1.6(b)(2)(A) and 12.1.6(d)(2). We recommend, however, that Clark revise s ubsection 12.1.6(d)(5) to clarify that this provision does not cover changes that may increase the sourc e’s PTE by “significant” amounts. Additionally, we note that the reference to paragraph (2)(E) in subsection 12.1.6(b) appears to be a typographical error and should be corrected by replacing (E) with (D).

Finally

, Section 12.1 is broadly deficient in one important respect. The d efinition of “minor source” in

7 While the Alabama Power court discusses the de minimis principle in the context of a Federal administrative agency’s authority in promulgating rules to satisfy statutory requirements, the same principle can be applied where a State promulgates rules to satisfy requirements by a Federal administrative agency. With regards to the de minimis principle, the Alabama Court writes: “Determination of when matters are truly de minimis naturally will turn on the assessment of particular circumstances, and the agency will bear the burden of making the required showing. But we think most regulatory statutes, including the Clean Air Act, permit such agency showings in appropriate cases. While the difference is one of degree, the difference of degree is an important one. Unless Congress has bee n extraordinarily rigid, there is likely a basis for an implication of de minimis authority to provide exemption when the burdens of regulation yield a gain of trivial or no value. That implied authority is not available for a situation where the regulator y function does provide benefits, in the sense of furthering the regulatory objectives, but the agency concludes that the acknowledged benefits are exceeded by the costs. For such a situation any implied authority to make cost

- benefit

decisions must be bas ed not on a general doctrine but on a fair reading of the specific statute, its aims and legislative history.” See Ala. Power Co. v. Costle , 636 F.2d 323, at 360

- 361 (D.C.Cir. 1979).16 s

ubsection 12.1.1(c) does not address PM 2.5 emissions. Pursuant to CAA section 110(a)(2)(C), States were required to amend their minor source programs to include direct PM 2.5 emissions and precursor emissions in the same manner as included for purposes of PM 2.5 major NSR . See 73 FR 28321, 28344 (May 16, 2008). Because Nevada has not yet submitted the required minor NSR SIP

revisions to address the 1997 PM 2.5 standard, EPA is proposing to disapprove the applicability provisions of Section 12.1 to the extent they do not address minor sources of PM 2.5 and PM 2.5 precursor emissions. This limited disapproval, if finalized, would require Clark to revise Section 12.1

to cover minor s ources of PM 2.5 and to submit the revised rule to EPA for approval into the Clark County portion of the Nevada SIP.

(f) The procedures must discuss the air quality data and the dispersion or other air quality modeling used to meet the requirements of this subpart. (1) All applications of air quality modeling involved in this subpart shall be based on the applicable models, data bases, and other requirements specified in appendix W of this part (Guidelines on Air Quality Models). (2) Where an air quality mo del specified in appendix W of this part (Guideline on Air Quality Models) is inappropriate, the model may be modified or another model substituted. Such a modification or substitution of a model may be made on a case

- by

- case basis or, where appropriate, o n a generic basis for a specific State program. Written approval of the EPA must be obtained for any modification or substitution. In addition, use of a modified or substituted model must be subject to notice and opportunity for public comment under proced ures set forth in 40 CFR 51.102.

Discussion : Although any air quality data or modeling used to meet a requirement in a minor NSR

program must comply with EPA’s requirements in 40 CFR part 51, appendix W, or an approved

alternative consistent with 40 CFR 5 1.160(f), EPA’s regulations do not specifically require that all minor source permit programs contain requirements for air quality modeling

. Because Section 12.1 does not require permit applicants to conduct air quality modeling analyses , the requirement in 40 CFR 51.160(f) related to air quality data and models does not apply to our evaluation. The absence of a specific air quality modeling provision in Section 12.1 is acceptable given the relatively insignificant portion of total statio nary source emissions attributed to minor sources in Clark County,

as discussed above. See Minor NSR SIP Submittal, Appendix D

– Emission Inventory Tables ; see also Memorandum to File dated July 10, 2012, Laura Yannayon, EPA Region 9, RE: “EPA evaluation

o

f Clark County minor source emissions,” including attachment, and Minor NSR TSD at 3

- 20, 3

- 21,

3

- 26 and 3

- 27.

2. 40 CFR 51.161

– Public availability of information

(a) The legally enforceable procedures in 40 CFR 51.160 must also require the State or

lo cal agency to provide opportunity for public comment on information submitted by owners and operators. The public information must include the agency’s analysis of the effect of construction or modification on ambient air quality, including the agency’s

pr oposed approval or disapproval.

Discussion : Section 12.1, subsection 12.1.5 requires Clark to provide an opportunity for public comment prior to issuing a permit for the construction or modification of three specific categories of17 minor sources. Clark est ablished these categories of minor sources based on a review of its emissions inventories and a conclusion that only these emission sources are environmentally significant

. See Minor NSR TSD at 3

- 3

, 3

- 4

. Specifically, s ubsection 12.1.5.3 (a) requires Clark to publish a notice of proposed action on an application for the following types of sources: (1) any new minor source with a potential to emit that exceeds 50 tpy for CO, 40 tpy for VOC,

SO 2 , or NO x , 15 tpy for PM 10

, or 0.6 tpy for lead

, (2) any new minor source that will be located within 1,000 feet of the outer boundary of a school, hospital, or residential area, and (3) any “significant permit revision ” that is required because of a “ significant ” (as defined in the rule) increase in an existing minor source’s potential to emit.

As discussed above, EPA regulations in 40 CFR 51.160(e) allow State NSR programs to exclude new minor sources and minor modifications from the NSR program so long as such sources and modifications are not environmentally significant, consistent with the de minimis exemption criteria

set forth in Ala. Power Co. v. Costle , 636 F.2d 323, at 360

- 361 (D.C. Cir. 1979). Given that 40 CFR 51.160(e) allows for sources and modifications that are not environmentally significant to b e excluded entirely from the NSR program, it follows that a State or local agency can choose to exempt some new sources or modifications subject to permitting from public participation requirements, but it must do so consistent with the de minimis principl es and by application of well

- defined objective criteria. Thus, EPA believes that 40 CFR 51.161(a) allows for the tailoring of the public participation process for less environmentally significant sources and modifications. See, generally, 60 FR 45530,

at 45548

- 45549 (August 31, 1995)

. Section 12.1 essentially treats all sources not covered by the public notice provisions in subs ection 12.1.5.3(a)(1) as de minimis

. W e believe that the se emissions

- based thresholds represent well

- defined objective criteria and, based on Clark ’s
documentation of the relatively insignificant portion of total inventoried emissions attributed to minor stationary sources in Clark County ( See Minor NSR SIP Submi ttal, Appendix D

– Emission Inventory

Tables ; see also Memorandum to File dated July 10, 2012, Laura Yannayon, EPA Region 9, RE: “EPA evaluation of Clark County minor source emissions,” including attachment, and Minor NSR

TSD at 3

- 20, 3

- 21, 3

- 26 and 3

- 27) we find that the thresholds established in subsection 12.1.5.3(a)(1) are reasonably calculated to exclude from mandatory public participation only less environmentally significant sources and modifications. This is acceptable.

(b) For the purposes of par agraph (a) of this section, opportunity for public comment shall include, as a minimum, (1) Availability for public inspection in at least one location in the area affected of the information submitted by the owner or operator and of the State or local

age ncy’s analysis of the effect on air quality; (2) A 30

- day period for submittal of public comment; and (3) A notice by prominent advertisement in the area affected of the location of the source information and analysis specified in paragraph (b)(1) of this section.

Discussion : Section 12.1 establishes adequate public participation procedures for those new sources or modifications subject to public notice under subsection 12.1.5.3(a)(1) . For instance,

s

ubsection 12.1.5.3 provides for notice to the public via publication of a Notice of Proposed Action in both a newspaper of general circulation in Clark County and on Clark ’s website, and specifies that all notices of proposed actions include the Control Of ficer’s preliminary determination whether the application for a permit should be approved. Subsection 12.1.5.3 also specifies that Clark ’s public18 notices must identify the location of the administrative record and information on how the public can

obtain a dditional information such as the draft permit, statement of basis, application, and other relevant supporting materials. The rule establishes a 30

- day comment period for submission of

written comments. These provisions are acceptable to satisfy this requi rement.

(c) Where the 30

- day comment period required in paragraph (b) of this section would conflict with existing requirements for acting on requests for permission to construct or modify, the State may submit for approval a comment period which is consi stent with such existing requirements.

Discussion : This is a discretionary component of a permit program that Clark’s submitted regulations

do not contain. All permits subject to public notice requirements under Section 12.1 are subject to a

30

- day public comment period

. This is acceptable

.

(d) A copy of the notice required by paragraph (b) of this section must also be sent to the EPA through the appropriate Regional Office, and to all other State and local air pollution control agencies having jurisdiction in the region in which such new or modified installation will be located. The notice also must be sent to any other agency in the region having responsibility for implementing the procedures required under this subpart. For lead, a copy of the notice is required for all point sources. The definition of point source for lead is given in 40 CFR 51.100(k)(2).

Discussion : Subsection 12.1.5.3 requires that Clark notify officials and agencies having jurisdiction over the location where the prop osed construction would occur. It also requires that a notice be sent to EPA if the project i s for a voluntarily accepted emission limit (i.e., if the action crea tes a synthetic minor source). For other minor source actions, the rule requires that the notice be sent to EPA upon EPA’s request

. With respect to any “point source” of lead ( i.e., any stationary source that actually emits a total of 5 tpy or more, see 40 CFR 51.100(k)), the requirement is met because the public procedures in subsection 12.1.5.3 apply to any new minor source with a PTE that exceeds 0.6 tpy for

lead. This provision is acceptable to satisfy this requirement.

3. 40 CFR 51.162

– Identification of responsible agency

Each plan must identify the State or local agency which will be responsible for meeting the requirements of this subpart in each area of the State. Where such responsibility rests with an agency other than an air pollution control agency, such agency will consult with the appropriate State or local air pollution contro l agency in carrying out the provisions of this subpart.

Discussion : Nevada law identifies the State Department of Conservation and Natural Resources (DCNR) as the State agency responsible for issuing permits to new or modified sources in all areas

of the State of Nevada, except within counties whose populations exceed 100,000. In such counties, Nevada law provides that the applicable permitting agency is the district board of health, county board of health or board of county commissioners. See NRS 445B.30 0 and NRS 445B.500, both of which were approved on August 31, 2006 (71 FR 51766). Clark County is one of only two counties in19 Nevada whose populations exceed 100,000

, and the County has its own air pollution control agency.

Section 12.0 identifies Clark as the agency that will be implementing stationary source permitting requirements in Clark County , including Section 12.1

.

The only exception to this basic regulatory structure for permitting of sources in Nevada relates to certain power plants that are sub ject to State, not county, jurisdiction notwithstanding their location

within Clark County . See NRS 445B.500(5), approved into the SIP as noted above ; see also Section 12.0, subsection 12.0. 1 . Thus, the Nevada SIP identifies the State or local agency which is responsible for meeting the requirements of 40 CFR part 51, subpart I, in Clark county

.

4. 40 CFR 51.163

– Administrative procedures

The plan must include the administrative procedures, which will be followed in making the determination specified in paragraph (a) of 40 CFR 51.160.

Discussion : Section 12.1 provides adequate administrative procedures to be followed by Clark in making the determinations specified in 40 CFR 51.160(a), including application requirements, and specifically, requirements fo r environmental evaluations, as well as completeness determinations, preliminary findings, public participation, and considerations in the final decision to issue or deny a permit. See, e.g., subsections 12.1.3, 12.1.4, and 12.1.5.

5. 40 CFR 51.164

– Stac k height procedures

Such procedures must provide that the degree of emission limitation required of any source for control of any air pollutant must not be affected by so much of any source’s stack height that exceeds good engineering practice or by any o ther dispersion technique, except as provided in 40 CFR 51.118(b). Such procedures must provide that before a State issues a permit to a source based on a good engineering practice stack height that exceeds the height allowed by 40 CFR 51.100(ii)(1) or (2) , the State must notify the public of the availability of the demonstration study and must provide opportunity for public hearing on it. This section does not require such procedures to restrict in any manner the actual stack height of

any source.

Discuss ion : 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 sati sfy the criteria of set forth in CFR 51.118(b). While such requirements are included in subsection 12. 2. 7.1 , those provisions d o not apply to minor sources as required by 40 CFR 51.164. EPA is identifying the absence of such a provision as a deficiency and proposing to disapprove Section 12.1 with respect to this requirement. This limited disapproval, if finalized, would require Clark to revise Section 12.1 to include a provision meeting the requiremen t in 40 CFR 51.164 and to submit the revised rule to EPA for approval into the Clark County portion of the Nevada SIP

.20 Section 12.2

– Permit Requirements f or Major Sources i n Attainment Areas EPA offers States (and local air districts) two mechanisms by which to administer permitting programs for the prevention of significant deterioration (PSD) of air quality, established by Congress in part C of title I of the Act. First, where EPA has promulgate d the Federal PSD program in 40 CFR 52. 21 , EPA may delegate that permitting a uthority to a State or air district. The Federal PSD program in 40 CFR 52.21 currently applies throughout the State of Nevada, except with respect to sou rces under Clark’s jurisdiction

. See 40 CFR 52.1485 and 47 FR 26621 (June 21, 1982)

, as amended 48 FR 28271 (June 21, 1983), 68 FR 11323 (March 10, 2003) and 68 FR 74489 (December 24, 2003)

. Effective May 27, 1983, EPA delegated to NDEP full authority to implement the Federal PSD program with respect to sources under NDEP ’s jurisdiction , including

p lants which generate electricity by using steam produced by the burning of fossil fuel within the

State of Nevada

. NDEP now administers th is Federal PSD program under a delegation agreement

with EPA executed October 19, 2004, as amended September 15, 2011

. 8 As a result, NDEP

administers the Federal PSD program as it applies to major new or major modifications at plants which generate electricity by using steam produced by the burning of fossil fuel in Clark County.

Alternatively, a State or air district ma y develop its own PSD program meeting the requirements of 40 CFR 51.166, and submit these rules for in clusion in the applicable SIP. Sources under Clark’s jurisdiction have been subject to a SIP

- approved PSD program since June 21, 1982 (47 FR 26621)

. We di scuss below the criteria for approval of a State/local PSD permitting program and our

evaluation of Clark’s NSR SIP submittal in accordance with these requireme nts

.

1. Provisions, pursuant to 40 CFR 51.166(a)(7), which incorporate the requirements in 40

C FR 51.166(a)(7)(i) through (a)(7)(vi) regarding applicability of PSD program requirements.

Discussion : Section 12.2, subsection 12.2.1 ( Applicability Procedures ) contains all of the applicability procedures for sources located in areas designated as attainment or unclassifiable under the CAA.

Subsection 12.2.1.4 ( Projects ) addresses the specific requirements of 40 CFR 51.166(a)(7).

2

. Applicable d efinitions foun d in CAA sections 169 and 169A(g), and i n 40 CFR 51.100 and 51.166(b). EPA has reviewed the definitions in Clark Sections 0 and 12.2. In most cases, the Clark definitions are either identical or nearly identical to the definitions in the CAA

and EPA’s implementing regulations

. In some cases, however, the Clark definitions do not

track the language in the f ederal definitions as closely. We explain below in more detail our proposed determinations as to whether the se definitions are equivalent to the feder al definitions and, therefore, adequate to meet th ese requirement s of a PSD program

.

8 See “Agreement for Delegation of the Federal Prevention of Significant Deterioration (PSD) Program by the United States Environmental Protection Agency, Region 9 to the Nevada Division of Environmental Protection,” executed September 15, 2011. For sources locating in Washoe County, the Washoe County District Health Department administers the Federal PSD program under a delegation agreement with EPA executed March 13, 2008.21 A. Definitions That Diffe r From EPA Definition s in 40 CFR 51.166

Allowable emissions Section 51.166 defines this term as “the emissions rate of a stationary source calculated using the maximum rated capacity of the source (unless the source is subject to federally enforceable limits which restrict the operating rate, or hours of operation, or both) and the most stringent of several types of emission limits, including “[t]he emissions rate specified as a federally

enforceable permit condition.” 40 CFR 51.166(b)(16) (emphases added). Clark’s definition in

subsection 12.2.2( b

) uses the term “p ractically enforceable” in lieu of “federally enforceable” and allows permit conditions with future compliance dates to be used to determine allowable

emissions

. Use of the term “practically enforceable” instead of “federally enforceable” is permissible only if the rule includes criteria by which a limit will be judged to be practically enforceable by Clark County

. See, e.g., "Guidance on Limiting Potential to Emit in New Source Permitting," June 13, 1989; “Options for Limiting the Potential to Emit (PTE) of a Stationary Source Under Section 112 and Title V of the Clean Air Act (Act) ,” January 25, 1995 ( a “practicably enforceable” permit limit must generally specify a technically

- accurate limitation

, time period ( s

) for the limitation

, and method s to determine compliance including appropriate monitoring, recordkeeping, and reporting). The absence of any such criteria is a deficiency.

In addition, because permit conditions with future compliance dates generally are not practically enforceable at the time of permit evaluation, such permit conditions cannot provide a basis for calculating allowable emissions. We there fore propose to disap prove this definition. This limited disapproval, if finalized, would require Clark to revise the definition of “allowable emissions” to: (1) provide criteria for determining whether a particular limit is “practically enforceable” consistent with EPA policy , and (2) delete the reference to permit conditions with future compliance dates.

Baseline actual emissions
The definition of the term “Baseline Actual Emissions” (BAE) in subsection 12.2.2(c) varies in

several respect s from EPA’s definition in 40 CFR 51.166(b) (47)

.

First, although EPA’s definition of BAE requires the inclusion of emissions associated with

malfunctions (see 40 CFR 51.166(b)(47)(i)( a

) and (ii)( a)

)

, paragraphs (1)(A) and (2)(B) of

subsection 12.2.2(c) require s the exclusion of “emissions from a shutdown associated with a

malfunction

. ” However

, the definition of the term “Projected Actual Emissions” in paragraph (nn)(1)(C) of subsection 12.2.2 also require s exclusion of emissions from a shutdown associated

with a malfunction

. On balance EPA believes this approach will result in equivalent or higher estimates of emission increases for modified emission units, since the emissions associated with

future malfunctions should generally be estimated as the same or less when using newer modified equipment than malfunction

- related emissions in a baseline year

. Therefore

, the omission of the requirement to include malfunction emissions in the BAE is acceptable.

Second, paragraph (1)(B)(i) of subsection 12.2.2(c) includes a requirem ent to adjust the BAE

downward to “exclude any emissions that would have exceeded an emission limitation with which the major stationary source must comply as of the particular date , had such major22 stationary source been required to comply with such limitations during the consecutive 24

- month period ” (emphasis added). EPA’s definition of BAE in 40 CFR 51.166 includes a similar provision

for existing non

- electric utility steam generating units (non

- EUSGUs) but requires a downward adjustment in BAE “to exclude any emissions that would have exceeded an emission limitation with which the major stationary source must currently comply, had such major stationary source been required to comply with such limitations during the consecutive 24

- month period.” 40 C FR 51.166(b)(47)(ii)( c

). T he reference in paragraph (1)(B)(i) to an emission limitation that applied “as of the particular date” instead of an emission limitation with which the source must “currently comply” is problematic, as it is not clear which “parti cular date” the definition refers to. We propose to disapprove this provision. This limited disapproval, if finalized, would require Clark to

revise the definition of BAE to define “particular date.”

We note, however, that t o the extent that Clark intended to apply the requirement in 40 CFR 51.166(b)(47)(ii)( c

) (which only applies to non

- EUSGUs)

, to both EUSGUs and non

- EUSGUs, this is acceptable as it ensures that the calculation of BAE in both cases will exclude emissions

that exceed current emissi on limitations.

We also recommend that sub paragraph (1)(B)(i) be relabeled as a separate paragraph ( (1)( C

)

or

(1)( E ) ) under subsection 12.2.2(c) , as it is not appropriate to characterize it as a subset of paragraph (1) (B). See 40 CFR 51.166(47)( ii). Other provisions that cross

- reference

sub paragraph (1)(B)(i) will then need to be revised accordingly. For example, paragraph (1)(D)

will need to be revised to include a reference to the new paragraph ( current subparagraph (1)(B)(i)

, relabeled as appr opriate). See 40 CFR 51.166(47)(ii)( e

).

Net emissions increase
The definition of the term “Net Emissions Increase” (NEI) in subs ection 12.2.2(ii) varies in several respects from EPA’s definition in 40 CFR 51.166(b)(3)

.

Specifically, Clark’s definition of NEI includes three subparagraphs under subsection (1)(C) that

are not included in EPA’s definition of NEI in 40 CFR 51.166 (b)(3)

. These three subparagraphs appear to establish requirements for calculating “actual emissions after the contemporaneous

pro ject

, ” but it is not clear w hat purpose these calculations serve and also not clear which project

the term “contemporaneous project’ refers to (e.g., the project under review or a previous project that resulted in a creditable emission increase or decrease during the “ contemporaneous ” period

a s defined in subsection (2) )

. EPA’s definition of NEI provides that a source owner/operator may

take into account those increases or decreases in actu al emissions that are “contemporaneous with the increase from the particular change,” i .e., that occur “within a reasonable period (to be specified by the State) before the date that the increase from the particular change occurs. ” 40 CFR 51.166(b)(3)(ii) (emphasis added)

. This definition does not call for an y assessment of

actual emissions after a c ontemporaneous project ; only those increases and decreases that are

“ contemporaneous ” with the project under review may be considered

.

Additionally, s ubparagraph (1)(C)(ii) allows for actual emissions to be determined based on projected actual emissions (PAE) if the Control Officer determines that there is no sufficiently23 representative time period to determine “ actual emissions after a contemporaneous project. ”
EPA ’s regulations do not allow for the use of PAE in the calculation of NEI

. 40 CFR 51.166(b)(3).

We propose to disapprove this provision. This limited disapproval, if finalized, would require

Clark to remove paragraphs (1) (C)(i ), (ii) and (iii) from the definition of NEI in s ubsection 12.2.2(ii) , and to submit the revised rule to EPA for approval into the Clark County portion of the

Nevada SIP

.

We note that paragraph (6) of subsection 12.2.2(ii) mirrors EPA’s provision in 40 CF R 51.166(b)(3)(vii) for replacement units that require shakedown except that, in addition to any “replacement unit ” (as defined in 40 CFR 51.166(b)(32)) , paragraph (6) provides that any other

“new emission unit that replace s an existing emissions unit and that requires shakedown” is also

allowed a reasonable shakedown period before the emission increase is considered to have occurred. This is acceptable.

Major modification The definition of the term “major modification” in subsection 12.2.2 (dd) states (in subparagraph (4)) that “[t]he fugitive emissions of a major stationary source shall not be included in determining, for any of the purposes of Section 12.2, whether a particular physical change or change in the method of operation is a major modification unless the major stationary source is a categorical stationary source or belongs to any other stationary source category which, as of August 7, 1980, is being regulated under Section 111 or 112 of the Act.” Although this language

is consistent with the text of 40 CFR 51.166 (b)(2) (v) as of July 1, 2010

, EPA has administratively stayed this paragraph indefinitely

, e ffective March 30, 2011 (76 FR 17548) (final rule effectuating and extending stay of the final rule entitled "Prevention of Significa nt Deterioration (PSD) and Nonattainment New Source Review (NSR): Reconsideration of Inc lusion of Fugitive Emissions" (“Fugitive Emissions Rule”) published December 19, 2008). The effect of this administrative stay

was to revert 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 cat egories

. 76 FR at
17550, 17551. The definition of “major modification” in subs ection 12.2.2(dd) is not consistent

with this approach to the treatment of fugitive emissions in applicability determinations

. We therefore propose to disapprove this definition. This limited disapproval, if finalized, would require Clark to revise Section 12.2 to require that fugitive emissions be included in major modification applicability determinations for all source categories.

Prevention of Significant Deterioration (PSD) Permit
The definition of this term in subs ection 12.2.2( ll ) is consistent with the definition of the term in EPA’s nonattainment NSR regulations in 40 CFR 51.165(a)(1)( xli ), rather than the PSD definition

in section 51.166(b)(42). As such, it omits the last sentence contained in EPA’s definition of the term “Prevention of Significant Deterioration (PSD) Program” in 40 CFR 51.166 (b) (42)

. Clark’s

definition of “ Prevention of Significant Deterioration (PSD) Permit ” in subs ection 12.2.2(ll) should

be revised to match the applicable PSD definition in 40 CFR 51.166, which include s a sentence reading “Any such permit is a major NSR permit

. ” We are not citing this as a deficiency but24 recommend that Clark revise subsection 12.2.2(ll) to include this additio nal language in the definition of “Prevention of Significant Deterioration (PSD) Permit.”

Projected actual emissions
The definition of the term “Projected Actual Emissions” (PAE) in subs ection 12.2.2(nn) varies slightly from EPA’s definition in 40 CFR 51.166(b) ( 40 )

. Although EPA’s definition of PAE requires the inclusion of emissions associated with malfunctions (see 40 CFR 51.166(b)(40)(ii)( b

)), paragraph (1)( C

) of subs ection 12.2.2(nn) requires exclusion of “emissions from a shutdown

associated with a malfunction.” As discussed above with regard to the definition of BAE, however, this is permissible because BAE also must exclude “emissions from a shutdown

associated with a malfunction.” EPA believes this approach will result in equivalent or higher

es timates of emission increases for modified emission units, since the emissions associated with future malfunctions should generally be equal to or less than malfunction

- related emissions in a baseline year. Therefore, the omission of the req uirement to inc lude malfunction

- related

emissions in PAE is acceptable.

B. EPA’s Revisions to Definitions in 40 CFR 51.166 S ince DAQ’s Adoption of Section 12.2

Subsequent to Clark’s adoption of Section 12.2, EPA revised the definition of “Regulated NSR Pollutant” in 40 CFR 51.166 (b) (49) through the following final rule s : (1) “ Implementation of the New Source Review (NSR) Program for Particulate Matter Less Than 2.5 Micrometers (PM 2.5 ),” dated May 16, 2008 (73 FR 28321)

, (2) “ Prevention of Significant Deterioration and Title V Greenhouse Gas Tailoring Rule,” dated June 3, 2010 (75 FR 31514)

, and (3) “Requirements for Preparation, Adoption, and Submittal of Implementation Plans, ” dated April 6, 2011 (76 FR 18870) (CFR correction notice ).

Discussion: The revised elements of EPA’s definition of “Regulated NSR Pollutant” now read as follows (with new language that subs ection 12.2 .2(pp) does not satisfy shown in underline):

Regulated NSR pollutant (51.166 (b)(49)(i) and (vi) only) : (i ) Any pollutant for which a national ambient air quality standard has been promulgated and any pollutant identified under this paragraph ( b)(49)(i ) as a constituent or precursor to such pollutant. Precursors identified by the Administrator for purposes of NSR are the following:

( a

) Volatile organic compounds and nitrogen oxides are precursors to ozone in all

attainment and unclassifiable areas.

( b

) Sulfur dioxide is a precursor to PM 2.5 in all attainment and unclassifiable areas.

( c

) Nitrogen oxides are presumed to be precursors to PM 2.5 in all attainment and unclassifiable areas, unless the State demonstrates to the Administrator's satisfaction or EPA demonstrates that emissions of nitrogen oxides from sources in a specific area are not a significant contributor to that area's ambient PM 2.5 concentrations.25 ( d

) Volatile organic compounds are presumed not to be precursors to PM 2.5 in any attainment or unclassifiable area, unless the State demonstrates to the Administrator's

satisfaction or EPA demonst rates that emissions of volatile organic compounds from sources in a specific area are a significant contributor to that area's ambient PM 2.5 concentrations.

(vi) Particulate matter (PM) emissions, PM 2.5 emissions, and PM 10 emissions shall include

gaseou s emissions from a source or activity which condense to form particulate matter at ambient temperatures. On or after January 1, 2011, such condensable particulate matter shall be accounted for in applicability determinations and in establishing emissions

l imitations for PM, PM 2.5 and PM 10 in PSD permits. Compliance with emissions limitations for
PM, PM 2.5 and PM 10 issued prior to this date shall not be based on condensable particular matter unless required by the terms and conditions of the permit or the applicable implementation plan. Applicability determinations made prior to this date without accounting

for cond ensable particular matter shall not be considered in violation of this section unless the applicable implementation plan required condensable particular matter to be included. [ Note: On March 16, 2012, EPA published a proposed rule entitled “Amendment to t he

D efinition of ‘R egulated NSR pollutant ’ Concerning Condensable Particulate Matter” ( 77 FR 15656) , which may upon finalization require additional revisions to Clark’s definitio n of “Regulated NSR pollutant.” ]

We therefore propose to disapprove Clark’s definition of “regulated NSR pollutant” in subsection 12.2.2(pp). This limited disapproval, if finalized, would require Clark to revise the definition of “Regulated NSR Pollutant” contained in Section 12.2 to incl ude the additional language in 40 CFR section 51.166(b)(49)(i) regarding precursors to ozone and PM 2.5 and section 51.166(b)(49)(vi) regarding condensable PM.

In addition, on October 20, 2010, EPA published a final rule entitled “ Prevention of Significant Deterioration (PSD) for Particulate Matter Less Than 2.5 Micrometers (PM 2.5 )

– Increments, Significant Impact Levels (SILs) and Significant Monitoring Concentration (SMC)” (75 FR 64864), which , among other things, establish ed PM 2.5 increments as minimum pro gram elements for all State PSD programs

. We are not identifying the absence of these requirements in Section 12.2 as a deficiency at this

time but note that Clark is required to submit , no later than July 20, 2012, a SIP revision that incorporates the final PM 2.5 increments or alternative measures that can be demonstrated to EPA's satisfaction to provide an equivalent level of protection as the

PM 2.5 increments. See 75 FR 64864 , 64898

. The relevant definitions in 40 CFR 51.166(b) now read as follows (with new language shown in underline):

Baseline area (40 CFR 51.166(b) (15)) (i) Baseline area means any intrastate area (and every part thereof) designated as

attainment or unclassifiable under 40 CFR Part 81 section 107(d)(1)(A)(ii) or (iii) of the Act in which the major source or major modification establishing the minor source baseline date would construct or would have an air quality impact equal to or greater than one (1) microgram per cubic meter (annual average) of the pollutant for which the minor source26 baseline date has been established; for the pollutant for which the baseline date is established, as follows: Equal to or greater than 1 μg/m3 (annual average) for SO 2 , NO 2 , or PM 10

; or equal or greater than 0.3 μg /m3 (annual average) for PM 2.5

.

(ii) Area redesignations under 40 CFR Part 81 section 107(d)(1)(A)(ii) or (iii) of the Act cannot intersect or be smaller than the area of impact of any major stationary source or major

modification which:

Major source bas eline date (51.166 (b)(14)(i) only) ( a ) In the case of particulate matter PM 10 and sulfur dioxide, January 6, 1975; and ( b ) In the case of nitrogen dioxide, February 8, 1988; and ( c ) In the case of PM 2.5, October 20, 2010.

Minor source baseline date (51.166 (b)(14)(iii)(a) only) ( a

) The area in which the proposed source or modification would construct is designated as

attainment or unclassifiable under section 107(d)(1)(A)(ii) or (iii) of the Act for the pollutant on the date of its complete appl ication under Section 12.2 of the AQRs; and

C. Additional terms in Section 12.2 The following terms are used in Section 12.2 but are not specifically defined in EPA ’s regulations in 40 CFR 51.166

. EPA has reviewed these terms and believes that they strengthen the program by providing clear definitions for terms used in Section 12.2.

These terms include the following: B asic design parameter

, Categorical stationary source

, Complete

, Shutdown and Startup

.

3. Provisions which establish the maximum allowable ambient air increments and ambient air ceilings as set forth in 40 CFR 51.166(c) and (d), for any designated attainment or

unclassifiable area.

Discussion : Subsections 12.2.3 ( Ambient Air Increments ) and 12.2.4 ( Ambient Air Ceilings ) , specify

ma ximum allowable ambient air increments and ambient air ceilings for PM 10 , SO 2 , and NO 2 consistent with EPA’s ambient air increments and ambient air ceilings for these pollutants. Section

12.2 does not include ambient air increments for PM 2.5 but as noted above, PSD SIP revisions establishing PM 2.5 increments are not due until July 20, 2012. The provisions of subs ection 12.2.3

and subs ection 12.2.4 therefore satisfy current requirements but will soon need to be revised to address the required increments for PM 2.5

. See 75 FR 64864 (October 20, 2010).

4. Provisions concerning the initial designation of all attainment areas as Class I, II, or III, as listed in 40 CFR 51.166(e) and (g).

Discussion : Section 12.2, subsections 12.2.5 and 12.2.6 cont ains provisions concerning designation of areas consistent with 40 CFR 51.166(e) and (g ). Because there is no federally required Class I area in Clark County and all other areas are designated as Class II (see subsection 12.2.6.1),

Section 12.2 meets this requirement.27 5. Provisions, pursuant to 40 CFR 51.166(h), to assure that the degree of emission limitation required of any source for control of any air pollutant must not be affected by so much of any source's stack height that exceeds good engineering p ractice.

Discussion : Section 12.2, subsection 12.2.7 ( Stack Heights ) , contains provisions concerning stack height and associated emission limitations. This provision satisfies th e regulatory requirement

.

6. Provisions, pursuant to 40 CFR 51.166(i ), which allow for specified exemptions from the PSD program at the State’s election

.

Discussion : Section 12.2, subsection 12.2.8 ( Exemptions ) , contains specific exemptions for non profit health or nonprofit educational institutions

, and for portable stat ionary sources in specific

circumstances ; both of which are consistent with the provisions of 40 CFR 51.166(i).

7

. Provisions, pursuant to 40 CFR 51.166(j), which require BACT, determined on a

case

- by

- case basis, for a new major source or major modification.

Discussion : Section 12.2 requires BACT for all new major sources or major modifications.

S ubs ection 12.2.9.1 requires a new major stationary source to apply BACT for each regulated NSR pollutant that it would have the potential t o emit in si gnificant amounts. For major modifications,

subsection 12.2.9.2 requires BACT for each regulated NSR pollutant for which there is a significant net emissions increase at the stationary source.

PSD review, including control technology review, also applies to certain non

- criteria pollutants such as particulate matter, green house gases (GHG), fluorides (except hydrogen fluoride), sulfuric acid mist, hydrogen sulfide, total reduced sulfur, reduced sulfur compounds, municipal waste combustor organics, metals, and acid gases, municipal solid waste landfill emissions, and pollutants regulated

under title VI of t he Act (e.g., CFCs and HCFCs). New or modified sources of such non

- criteria pollutants are covered by the definition s of the terms “regulated NSR pollutan t” and “significant” in

subsection 12.2.2, which identify each of these pollutants and establish significant net emissions

increase thresholds that match the federal thresholds. These provisions satisfy the regulatory requirements.

8. Provisions, pursuan t to 40 CFR 51.166(k), which address the requirements for a source impact analysis.

Discussion : Section 12.2, subsection 12.2.10 ( Source Impact Analysis ) , contains all of the specified provisions to address source impact analysis requirements. This provision satisfies the regulatory requirement

.

9

. Provisions pursuant to 40 CFR 51.166(l) requiring air quality modeling consistent with the applicable requirements of appendix W of 40 CFR part 51 (“Guideline on Air Quality Models”)

, and provisions pursu ant to 40 CFR 51.166(m) to assure that a major source or major modification will perform an air quality analysis, including pre

- application air28 monitoring for any pollutant for which the net emissions increase of the source or modification is significant, and post

- construction monitoring as necessary to determine the effect the emissions may have, or are having, on air quality in any area.

Discussion : With respect to both criteria and non

- criteria air pollutants, subsection 12.2.12, Air Quality Analysis, s atisfies the requirement for an air quality analysis including pre

- application and post

- construction monitoring req uirements. S ubs ection 12.2.11, Air Quality Models, requires that all estimates of ambient concentrations be based on applicable air quality models, databases, and other requirements specified in 40 CFR Part 51, Appendix W (“Guideline on Air Quality Models”), except where EPA approves a modification or substit ution to such a model following public notice and opportunity for comment

. These provi sions satisfy the regulatory requirements.

10. Provisions, pursuant to 40 CFR 51.166(n), requiring the submission of all information necessary to perform any analysis or make any determination required under the PSD

program

.

Discussion : Section 12.2, s ubsection 12.2.13 ( Source Information ) , contains all of the specified provisions to require that permit applicant s submit all information necessary to perform any analysis or make any determination required under Section 12.2

. This provision satisfies the regulatory requirement

.

11

. Provisions, pursuant to 40 CFR 51.166(o), to assure that the owner of operator of a major source or major modification will perform additional impact analyses of the impairment to visibility, soils , and vegetation and the air quality impact projected for the area as a result of general commercial, residential, industrial and other growth associated with the source

or modification.

Discussion : S ubs ection 12.2.14 ( A dditional Impact Analyses ) , include s the provisions necessary to assure that the required additional impact analyses are performed.

12

. Provisions to assure protection of air quality related values (including visibility) in Class I areas pursuant to 40 CFR 51.166(p).

Discussion : The requirements for protection of air quality related values (AQRV) (including visibility) are found in section 165(d)(2) of the Act, 40 CF R 51.166(p) and 40 CFR 51.307. These requirements include notification of a permit application to the Federal land manag er (FLM) and the Federal official charged with direct responsibility for management of any lands within a Class I area which may be affected by emissions from a proposed major source or major modification. Also, the PSD program must provide a mechanism whe reby an FLM or other Federal official may present to the permitting authority, after the reviewing authority’s preliminary determination, a demonstration that the emissions from the proposed source or modification would have an adverse impact on the AQRV ( including visibility) of any Federal mandatory Class I lands, notwithstanding that the change in air quality resulting from emissions from such source or modification would not cause or contribute to

concentrations which would exceed the maximum allowable increases for a Class I area. If the29 reviewing authority concurs with such demonstration, the reviewing authority must not issue the permit.

Clark County lies within the proximity (i.e., within 100 kilometers) of Grand Canyon National Park, a

Federal Mand atory Class I area. Zion National Park, another Federal Mandatory Class I area, lies just beyond the 100 kilometer distance. Clark S ection 12.2, s ubs ection 12.2.15 ( A dditional Requirements for Sources Impacting Class I Areas ) requires additional Class I are a analyses under

c

ertain circumstances and provides a framework for coordination between Clark and the FLM (or other relevant Federal official) concerning potential impacts on Class I areas

. These provisions meet the regulatory requirements.

Subs ection 12.2.15.2 requires the Control Officer to consult with the FLM on a proposed major stationary source or major modification that may impact visibility in any Class I Area, in accordance

with 40 CFR 51.307. This is acceptable to meet the visibility el ement of this requirement.

13. Provisions to assure agency and public participation under 40 CFR sections 51.166(p)(1) and 51.166(q).

Discussion : Prior to public review : Section 165(d)(1) of the Act, which is also set forth at 40 CFR

51. 166(p)(1), requires the PSD reviewing authority to transmit to EPA a copy of each permit application relating to a major new source or major modification and to provide notice to EPA of every

action related to the consideration of such permit. S ection 12 .2

, s

ub sectio n 12.2.15.1 ( Notice to EPA ) requires the Control Officer to “transmit to the Administrator a copy of each permit application relating to a major stationary source or major modification, and provide notice to the Administrator of every

action related to the consideration of such permit.” This provides for the necessary coordination with

EPA. Because NDEP shares PSD increment

- tracking responsibility with Clark for baseline areas inside Clark County, we recommend that Clark revise subsection 12.2.15.1 at the e arliest possible opportunity to provide for copies of permit applications to also be sent to NDEP. NDEP coordination should also occur prior to public review to ensure proper analysis of increment consumption. We do not consider this oversight to be an app rovability issue.

Discussion : Public review : S ection 12.2, s ubsection 12.2.16 ( Public Participation ) , complies with the public participation requirements in 40 CFR 51.166(q).

14. Provisions, pursuant to 40 CFR 51.166(r), which address source obligation r equirements.

Discussion : Section 12.2, subsection 12.2.17 ( Source Obligation ) , contains all of the specified provisions to ensure an applicant will meet all of the required source obligation requirements. This provision satisfies the regulatory requirement

.

15. Provisions, pursuant to 40 CFR 51.166(w), which address Actuals PALs.

Discussion : Section 12.2, subsection 12.2.19 ( Plantwide Applicability Limits (PALs) ) closely mirrors all of the paragraphs contained in 40 CFR 51.166(w) , with one exc eption

. 40 CFR 51.166(w)(1 0 )(

v

) states that “[i]f the compliance date for a State or Federal requirement that applies to the PAL source30 occurs during the PAL effective period, and if the reviewing authority has not already adjusted for such requirement, th e PAL shall be adjusted at the time of PAL permit renewal or title V permit renewal, whichever occurs first ” (emphasis added). Subsection 12.2.19.10(e) states that “[i ]f the compliance date for a federal or state requirement that applies to the PAL source occurs during the PAL effective period, and if the Control Officer has not already adjusted for such requirement, the PAL shall be adjusted at the time the affected Pa rt 70 Operating Permit is renewed ” (emphasis added). Although P art 70 permits are generally renewed more frequently than PAL permit s

, at any given time it is possible that the expiration date for a PAL permit will occur before the expiration date

for a P ar t 70 permit. We propose to disapprove this provision because it is not consistent with EPA’s requirements for PALS in 40 CFR 51.166(w)(10)(v) . This limited disapproval, if finalized, would require Clark to revise subsection 12.2.19.10(e) to require adjustment of PALs to address additional compliance requirements at the time of PAL permit renewal or title V permit renewal, whichever

occurs first , consistent with 40 CFR 51.166(w)(10)(v)

.

Ad d itionally, EPA recommends that Clark revise subsection 12.2.1 9.2(a) to clarify the applicable

definitions. Subsection 12.2.19.2(a) currently states that the listed definitions apply and that “ [w]hen a term is not defined in these paragraphs, it shall have the meaning given in Section 0, Section 12.4

or the Act

. ” To the extent that Clark intended for the definitions provided in Section 12.2 (subsection 12.2.2) to apply before any of the other cited provisions , we recommend clarifying the provision accordingly

.

Section 12.3

– Permit Requirements f or Major Sources i n Nonattainment Areas Clark County is currently designated nonattainment for the PM 10 NAAQS and the 1997 8

- hour ozone NAAQS. 40 CFR 81.329. The Nevada State Environmental Commission (SEC), the administrative body responsible for the air quality regulations implemented by NDEP, has not adopted a preconstruction permit program that complies with part D of the Act (i.e., Nonattainment NSR) for the nonattain ment area s within Clark County. Generally , because NDEP has jurisdiction over a particular category of sta tionary sources in the ozone and PM 10 nonattainment area s within Clark County ( e.g ., Las Vegas , El Dorado and Ivanpah Valley s ), the

State is required to adopt and submit a Nonattainment NSR program for major new or modified sources within the applicable so urce category in the se nonattainment area s

. With respect to the

PM 10 nonattainment area in Clark County ( the Las Vegas planning area, hydrographic area 212)

and certain portions of the Clark County ozone nonattainment area ( i.e., the Las Vegas Valley (hydrographic area 212)

, El Dorado Valley (hydrographic area 167), Ivanpah Valley (hydrographic areas 164a and 164b) , and the city limits of Boulder City )

, EPA is not requiring the State to submit Nonattainment NSR rules because the Nevada SEC adopted a r egulation [Nevada Administrative Code (NAC) section 445B.22083] that prohibits the construction of new power plants or major modifications to existing power plants under State jurisdiction within the se area s

. 9
EPA approved NAC section 445B.22083 into the N evada SIP as part of our September 7, 2004 rulemaking. 69 FR 54006, 54019 (September 7, 2004). This action resolve d the regulatory gap that

would otherwise exist in connection with NSR for PM 10 sources under NDEP jurisdiction within

9 This construction prohibition applies within the following areas, with limited exceptions: (a) Las Vegas Valley, Hydrographic Area 212; (b) El Dorado Valley, Hydrographic Area 167; (c) Ivanpah Valley, Hydrographic Areas 164 a and 164 b; and (d) The city l imits of Boulder City. See NAC 445B.22083.31 the Las Vegas planning area, and for NO

x and VOC sources under NDEP jurisdiction within th o se portions of the Clark County ozone nonattainment a rea that are covered by NAC section

445B.22083

.

Several hydrographic areas within the Clark County ozone nonattainment area outside o f Las Vegas Valley, however, are not covered by NAC section 445B.22083: specifically, hydrographic areas 165, 166, 213, 214, and 216

- 218. See 40 CFR 81.329. 10 Although EPA has recently determined that Clark County is attaining the 1997 8

- hour ozone NAAQS (76 FR 17343), this determination did not affect NSR obligations for that standard. See 77 FR 28424, at Tables 2 and 3 (May 14, 2012). Thus, with respect to so urces under NDEP jurisdiction ( i.e., major new or modified plants which generate electricity by using steam produced by the burning of fossil fuel) within these portions of the Clark County ozone nonattainment area, NDEP remains obligated to implement Nona ttainment NSR requirements for the 1997 8

- hour ozone NAAQS. Pursuant to EPA’s recent classification of the area as “marginal” nonattainment for the 1997 8

- hour ozone standard effective June 13, 2012 (77 FR 28424, May 14, 2012), NDEP is now obligated to sub mit NSR SIP revisions for Clark County meeting the applicable requirements of subpart 2 of part D, title I of the Act, including an offset ratio of 1.1 to 1 for NO

x and VOC (see CAA 182(a)(4)) no later than June 13, 2013. Alternatively, NDEP may revise NAC section 445B.22083 to extend its construction prohibitions to these hydrographic areas and submit this revised rule to EPA for approval into the SIP.

The Act requires all States with nonattainment areas to submit a NSR program that contains the

followin g nonattainme nt NSR provisions. To demonstrate that Clark has met each provision, EPA

identifies the s ection(s) of the submitted NSR rules which s atisfy the listed requirement. Where necessary, a detailed discussion accompanies deficiencies in the rules th at have been identified through this review.

1. Provisions to assure that calculation of emissions offsets, as required by section 173(a)(1)(A), are based on the same emissions baseline used in the demonstration of reasonable further progress.

Discussio n : The requirements for offsets in Section 12.3, subsection 12.3.6 do not contain a provision to assure that emission offset calculations are based on the same emissions baseline used in the demonstration of reasonable further progress (RFP) for the releva nt NAAQS pollutant, where applicable. We therefore propose to disapprove Section 12.3 with respect the requirement in CAA section 173(a)(1)(A) regarding baseline emissions in the calculation of offsets. This limited disapproval, if finalized, would require Clark to revise Section 12.3 to include a provision requiring

that emissions offsets calculations be based on the same emissions baseline used in the demonstration of reasonable further progress for the relevant NAAQS pollutant (where applicable),

and to meet the additional requirements related to offset calculations in 40 CFR 51.165(a)(3). We note that the emissions inventories supporting the Las Vegas Valley PM 10 attainment and RFP

10 The ozone nonattainment within Clark County is defined in 40 CFR part 81 as “[t]hat portion of Clark County that lies in hydrographic areas 164A, 164B, 165, 166, 167, 212, 213, 214, 216, 217, and 218 but excludi ng the Moapa River Indian Reservation and the Fort Mojave Indian Reservation.”32 demonstration and the Clark County ozone redesignation request and maintenance plan are based

on actual emissions, and that Clark may meet the requirement in CAA section 173(a)(1)(A) by demonstrating that all PM 10 , NO x , and VOC ERCs used to satisfy offset requirements under Section 12.3 must, by definition, b e calculated based on reductions in actual emissions, consistent with these plans submissions. As currently drafted, however, the criteria in Section 12.3 for evaluation and approval of ERCs are not adequate to meet this requirement, as discussed in item # 3 below.

Regarding the amount of offsets that is necessary to show noninterference with RFP, EPA presumes that so long as a new source obtains offsets in an amount equal to or greater than the amount specified in the applicable offset ratio (or, where the statute does not specify an offset ratio, in an amount equal to or greater than 1:1), the new sour ce will not interfere with RFP. Table 12.3

- 1 in Section 12.3, subsection 12.3.6.5, establishes a 1:1 offset ratio for NO x and VOC in any area that is

“nonattainment without designation” and a 1:1 offset ratio for CO and PM 10 in any “serious

nonattainment area.” Th e Act does not specify an offset ratio for either PM 10 or CO

, and thus Clark’s offset ratio of 1:1 for these pollutants i s acceptable . As to CO, because EPA has redesignated Clark County as attainment for the CO NAAQS ( 75 FR 59090, September 27, 2010)

, neither the CO offset ratio nor any other portion of section 12.3 is applicable to any source for CO purposes at this time.

W

ith respect to ozone precursors (NO x and VOC), because Clark County was not initially classified under subpart 2 of part D, title I of the Act for the 1997 8

- hour ozone NAAQS

, Clark’s offset ratio of

1:1 for NO x and VOC is currently acceptable for purposes of meeting the NSR requirements in subpart 1 of part D, title I of the Act for this standard . On April 27 , 2012, however, EPA finalized its classification rulemaking for all former subpart 1 ozone nonattainment areas nationwide, and as part of that rulemaking we classified the Clark County ozone nonattainment area as “marginal ”
nonattainment for the 1997 8

- hour ozone standard. 77 FR 28424 ( May 14, 2012 ). Accordingly , the

State is now obligated to submit NSR SIP revisions meeting the applicable requirements of subpart 2 of part D, title I of the Act , including an offset ratio of 1.1 to 1 for NO x and VOC (see CAA 182(a)(4)),

no later than June 13, 2013

.

We also note that Clark’s use of the phrase “nonattainment without designation” in Table 12.3

- 1 is confusing, as any nonattainment area is, by definition, designated. As part of its rulemaking to incorporate the 1.1 to 1 offset ratio required pursuant to EPA’s subpart 2 classification of the Las Vegas Valley area for the 1997 8

- hour ozone NAAQS , Clark should revise Table 12.3

- 1 to clarify th at
th

e revised offset ratio for NO x and VOC applies throughout the “marginal” ozone nonattainment area in Clark County

.

2. Provisions to assure, pursuant to section 173(c)(1), that any emissions offsets obtained in conjunction with the issuance of a permit to a new or modified source must be enforceable by the time of issuance of the permit, and in effect by the time the new o r modified source commences operation.

Discussion : S ection 12.3, s ubs ection 12.3.6.4(a) states that “Internal emission reductions used to satisfy an offset requirement must be federally enforceable at the time of issuance of the Authority to

Construct Pe rmit containing the offset requirements.” S ubs ection 12.3.6.4(b) states that “...the decrease in actual emissions used to generate ERCs or internal emission reductions must occur by no later than the commencement of operation of the new or modified major sta tionary source

, ” with a33 limited exception for a new facilit y that replace s a facility being shut down to provide offsets

. Consistent with EPA’s definition of “net emissions increase” in 40 CFR 51.165(a)( 1 ) (vi)(A)

, under subsection 12.3.6.4(c) Clark may allow up to 180 calendar days for “shakedown or commissioning”

of such a new facility before the existing facility must cease operation. These provisions adequately

a ddress the requirements in CAA 173(c)(1) related to the point in time at which offsets mu st become

enforceable and reductions must occur

. As discussed below, however, other provisions in Section 12.3 render the program deficient with respect to the requirements for offsets in CAA 173(c)(1).

3. Provisions to assure that emissions increases from new or modified major stationary sources are offset by real reductions in actual emissions as required by section 173(c)(1).

Discussion : Section 12.3, subsection 12.3.6.6(a) states that “Emission reductions used to satisfy offset requirements must be real, surplus, permanent, quantifiable, and federally enforceable.” This provision is acceptable, but several related provisions in subsections 12.3.6.2 and 12.3.6.7 render the program in Section 12.3 deficient with respect to the offset requirements of C AA 173(c)(1). Specifically, Section 12.3 does not contain adequate criteria for determining whether certain emission reductions may qualify for use as offsets, as explained below.

Subsection 12.3.6.1 states that the determination whether an applicant has surrendered sufficient offsets prior to commencing operation requires, at minimum, compliance with the offset requirements

in subsection 12.3.6.2. S ubs ection 12.3.6.2 provides that “[p]ollutant

- specific emissions shall be offset with federally enforceable ERCs or with internal emission reductions” in accordance with specified criteria, but these criteria include references to criteria in a separate rule called Section 12.7. Similarly , subsection 12.3.6.7 provides necessary geographic limitations on emissions reductions used to satisfy offsets requirements but provides that certain emission reductions that do not occur at the “same major stationary source at which the increase in emiss ions occurs” may nonetheless qualify as “internal emission reductions” if such reductions “meet the requirements for ERCs prescribed by Section 12.7.” Because Section 12.7 is neither approved into the SIP nor included in the NSR SIP submittal, EPA cannot a pprove provisions that allow sources to comply with criteria specified in Section 12.7 in lieu of appropriate criteria in Section 12.3. We therefore propose to disapprove Section 12.3 with respect to the offset requirements in CAA section 173(c)(1) . This

l imited disapproval, if finalized, would require Clark to revise Section 12.3 to include criteria (or reference appropriate criteria in a separate, SIP

- approved rule) that will assure that emissions increases from new or modified major stationary sources ar e offset by real reductions in actual emissions, as required by CAA 173(c)(1)

.

In addition, subsection 12.3.6.3 allows for interpollutant trades between VOC and NO x emission reductions for purposes of satisfying offset requirements for ozone, and interpo llutant trades among

PM 2.5, SO 2 and NO x emission reductions for purpose of satisfying offset requirements for PM 2.5

. The provision for trading between VOC and NO x ERCs is not acceptable without a demonstration supported by air quality modeling that such tr ades will result in a net air quality benefit in the nonattainment area, or a requirement to submit any proposed interpollutant trade for offset purposes, on a case by case basis, to EPA for review and concurrence prior to issuance of the permit. See "Improving Air Quality with Economic Incentive Programs," January 2001, at 16.9 and 16.14. The provisions for PM 2.5 precursor trades are not consistent with 40 CFR 51.165(a)(11), which requires34 that emissions offsets obtained “shall be for the same regulat ed NSR pollutant unless interprecursor offsetting is permitted for a particular pollutant as specified in this paragraph” and provides that interpollutant trades between PM 2.5 and certain precursors are allowed only where those PM 2.5 precursors are specifi cally identified in the approved definition of “regulated NSR pollutant” and where “such offsets comply with the interprecursor trading hierarchy and ratio established in the approved plan for a particular nonattainment area.” Although Section 12.3 does no t currently apply to

PM 2.5 sources because Clark County is designated attainment/unclassifiable for the PM 2.5 NAAQS, we nonetheless propose to disapprove this provision because it is contrary to EPA requirements for

both ozone and PM 2.5 purposes. This limi ted disapproval, if finalized, would require Clark to revise Section 12.3 to prohibit interpollutant trades except where interprecursor offsetting is permitted for a particular pollutant consistent with the requirements of 40 CFR 51.165(a)(11) and EPA poli cy on interpollutant trades.

4. Provisions, pursuant to section 173(c)(2), to prevent emissions reductions otherwise required by the Act from being credited for purposes of satisfying the part D offset requirements.

Discussion : S ection 12.3, subs ection 1 2.3.6.6(a) states that “Emission reductions used to satisfy offset requirements must be real, surplus , permanent, quantifiable, and federally enforceable.” ( Emphasis added )

“Surp lus” is defined in 12.3.2 as “... an emission reduction that has not been relied on in any air quality program related to any SIP, that is not a Nevada SIP requirement, that is not a requirement of a state air quality program that has been adopted but is not in the Nevada SIP, is not credited in any federal reasonable further progress or other milestone demonstration, is not a requirement of a consent decree, is not a requirement of a federal rule that focuses on reducing criteria air pollutants or their precursors, and has not already been credited in any other air quality program. Th e purpose of requiring that emissions offsets be surplus is to prohibit double

- counting of emission reductions.” This definition is not adequate to ensure that emission reductions required by standards promulgated under CAA section 111 (New Source Performa nce Standards) or under CAA section 112 (National Emission Standards for Hazardous Air Pollutants) are not credited for purposes of satisfying part D offset requirements . We therefore propose to disapprove this provision. This limited disapproval, if

final ized, would require Clark to revise the definition of “surplus” in subsection 12.3.2 to ensure that emission reductions required by CAA section 111 or 112 standards are not treated as “surplus.”

5. Provisions, pursuant to section 173(a)(5), that, as a pre requisite to issuing any part D permit, require an analysis of alternative sites, sizes, production processes, and environmental control techniques for proposed sources that demonstrates that the benefits of the proposed source significantly outweigh the e nvironmental and social costs imposed as a result of its location, construction, or modification.

Discussion : Section 12.3 , subsection 12.3 .4 states that “Prior to issuance of an Authority to Construct Permit for a new major stationary source or major mo dification subject to Section 12.3, the applicant shall submit an analysis of alternative sites, sizes, production processes, and environmental control techniques for the proposed source that demonstrates, to the satisfaction of the Control Officer, that35 t he benefits of the proposed source significantly outweigh the environmental and social costs imposed as a result of its location, construction, or modification.” This provision satisfies the statutory requirement.

6. Definition of “ stationary source ” that includes certain internal combustion engines subject to control under State programs (i.e., those not used for transportation purposes), but excluding the category of “ nonroad engines. ” [See section 302(z) of the Act.]

Discussion : S ection 12.3, subs ection 12.3.2(pp) defines a stationary source as “any building, structure, facility, or installation which emits or may emit a regulated NSR pollutant.” This is consistent with EPA’s definition of the term in 40 CFR 51.165(a)(1)(i) . Although this definitio n does not explicitly include internal combustion engines not used for transportation purposes or exclude “nonroad engines

, ” this is acceptable provided Clark interprets its definition consistent with the statutory definition of “stationary source” in CAA 302(z) and no contrary definition applies

.

7. Provisions, pursuant to section 173(a)(3), to assure that owners or operators of each proposed new or modified major stationary source demonstrate that all other major stationary sources under the same ownership in the State are in compliance with the Act.

Discussion : S ection 12.3, subs ection 12.3.3 ( Statewide Compliance ) , states that “Prior to issuance of an Authority to Construct Permit for a new major stationary source or major modification subject to Section 12.3, the applicant shall either demonstrate that each existing major stationary source owned or operated by the applicant in the state of Nevada is in compliance with all applicable emission limitations and standards under the Act or is in comp liance with an expeditious schedule which is federally enforceable or contained in a court decree.” This provision satisfies the statutory requirement.

8. Applicable definitions found in CAA section 171 , and in 40 CFR 51.100 and 51.165(a)(1).

EPA has revi ewed the definitions in Sections 0 and 12.3. In most cases, the Clark definitions are either identical or nearly identical to the definitions in the CAA and EPA’s implementing regulations. In some cases, however, the Clark definitions do not track the lang uage in the federal definitions as closely. We explain below in more detail our proposed determinations as to whether these definitions are equivalent to the federal definitions and, therefore, adequate to meet these requirements of a NSR program.

A. Def initions That Differ From EPA Definitions in 40 CFR 51.16 5

Baseline actual emissions (BAE) The definition of the term “Baseline Actual Emissions” (BAE) in subsection 12.3.2(c) varies in several respects from EPA’s definition in 40 CFR 51.165(a) (1)(xxxv)

.

First, although EPA’s definition of BAE requires the inclusion of emissions associated with malfunctions (see 40 CFR CFR 51.165(a)(1)(xxxv) ), paragraphs (1)(A) and (2)(B) of subsection 12.3.2(c) require s the exclusion of “emissions from a shutdown associ ated with a malfunction.” However, the definition of the term “Projected Actual Emissions” in paragraph (hh)(1)(C) of36 subsection 12.3.2 also requires exclusion of emissions from a shutdown associated with a malfunction. On balance EPA believes this approac h will result in equivalent or higher estimates of emission increases for modified emission units, since the emissions associated with future malfunctions should generally be estimated as the same or less when using newer modified equipment than malfunctio n

- related emissions in a baseline year. Therefore, the omission of the requirement to include malfunction emissions in the BAE is acceptable.

Second, paragraph (1)( C

) of subsection 12.3 .2(c) includes a requirement to adjust the BAE

downward to “exclude a ny emissions that would have exceeded an emission limitation with which the major stationary source must comply as of the particular date , had such major stationary source been required to comply with such limitations during the consecutive 24

- month period ” (emphasis added). EPA’s definition of BAE in 40 CFR 51.165 includes a similar provision for existing non

- electric utility steam generating units (non

- EUSGUs) but requires a downward adjustment in BAE “to exclude any emissions that would have exceeded an emission limitation with which the major stationary source must currently comply, had such major stationary source been required to comply with such limitations during the consecutive 24

- month period.” 40 CFR 51.165(a)(1)(xxxv ) (B)( 3

) . The reference in subs ection 12.3.2(c) (1)(C) to an emission limitation that applied “as of the particular date” instead of an emission limitation with which the source must “currently comply” is problematic, as it is not clear which “particular date” the definition

refers to. We propose to disapprove this provision. This limited disapproval, if finalized, would require Clark to revise the definition of BAE to define “particular date.”

We note, however, that to the extent that Clark intended to apply the requirement in 40 CFR

5

1.165(a)(1)(xxxv)(B)( 3

) (which only applies to non

- EUSGUs), to both EUSGUs and

non

- EUSGUs, this is acceptable as it ensures that the calculation of BAE in both cases will

exclude emissions that exceed current emission limitations.

Major Modification
The d efinition of this term 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 perm anent Clean Coal Technology Demonstration Project that constitutes repowering; and (2) the reactivation of a very

clean coal

- fired electric utility steam generating unit . See Section 12.3, subsection 12.3.2(x), paragraph (3)(I) and (J). Although such exemptions are acceptable for purposes of PSD review, they are not permissible for Nonattainment NSR purposes. S pecifically, s ection 415 of the CAA provides that permanent clean coal technology demonstration projects that constitute repowering as defined i n CAA section 402(12) are exempt from the PSD requirements of part C of title I of the Act with respect to “ any pollutant the potential emissions of which will not increase as a result of the demonstration project

. ” CAA 415(b)(3); 40 CFR 51.166( b

) (2)(iii)( j )

. Section 415 of the Act provides that reactivation of a “very clean unit” at a coal

- fired utilit y shall not subject the unit to PSD requirements where , among other things, the unit is equipped prior to shut

- down with a continuous system of emissions con trol that achieves specified removal efficienc ies for SO 2 and particulates and is equipped with low

- NO x burners prior to commencement of operations

. CAA 415(c); 40 CFR 51.166(b)(2)(iii)( k

) , (b)(36)

. Such demonstration projects are not, however, exempt from the Nonattainment NSR requirements of part D of title I of the Act. Since there is no37 statutory basis for these exclusions in a nonattainment NSR program, we are proposing to disapprove the definition of “major modification” in subsection 12.3.2(x)

. T his limited disapproval, if finalized, would require Clark to revise the definition of “major modification” in subsection 12.3.2(x) to delete paragraphs (3)(I) and (J).

Additionally, the definition of the term “major modification” in subsection 12.3.2(x) also requires

exclusion of fugitive emissions from the applicability determination unless the major stationary source is a categorical stationary source or belongs to any other stationary source category which, as of August 7, 1980, was being regulated under Section 111 or 112 of the Act.” Although this language is consistent with the t ext of 40 CFR 51.165(a)(1)(v)(G) as of July 1, 2010, EPA has administratively stayed this paragraph indefinitely, effective March 30, 2011 (76 FR 17548) (final rule effectuating and extending stay of the final rule entitled "Prevention of Significant

Deter ioration (PSD) and Nonattainment New Source Review (NSR): Reconsideration of Inclusion of Fugitive Emissions" (“Fugitive Emissions Rule”) published December 19, 2008). The effect of this administrative stay was to revert 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. 76 FR at 17550, 17551. The definition of “major modification” in subsection 12.3.2(x) is not consistent with this approach to the treatment of fugitive emissions in applicability determinations. We therefore propose to disapprove this definition. This disapproval, if finalized,

woul d require Clark to revise Section 12.3 to require that fugitive emissions be included in major modification applicability determinations for all source categories.

Major Stationary Source
This definition contains a small t ypographical error, in that subsections (2)(A) and (2)(B) should

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

Regulated NSR Pollutant The definition of “regulated NSR pollutant” in subsection 12.3.2(ii) does not satisfy current requirement s regarding “condensable particular matter” in NSR applicability determinations. EPA’s definition of “regulated NSR pollutant” in 40 CFR 51.165(a)(xxxvii) includes a paragraph (D) stating that on or after January 1, 2011, “gaseous emissions from a source o r 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 particulate matter (PM), PM 2.5 and PM 10 in NSR permits. See 73 FR 28321.We are proposing to disapprove this provision. This limited disapproval, if finalized, would require Clark to revise the definition of “regulated NSR pollutant” in subsection 12.3.2(ii) to include language

consistent with 40 CFR 51.165(a)(xxxvii)(D).

C. Additional terms The following terms are used in Section 12.3 but are not specifically defined in EPA’s regulations in 40 CFR 51.165. EPA has reviewed these terms and believes that they strengthen the program by providing clear definitions for terms used in Section 12.3.38 These terms include the following: B asic design parameter, Categorical stationary source, Complete , Emission Reduction Credit (ERC). In addition, we note that the definition of the term

“ Categorical stationary source

- list of 28”, lists Municipal inciner ators capable of charging more than 50 tons of refuse per day, rather than 250 tpy (see 40 CFR 51.165(a)( 1)(iv)(C)( 8

) ) . We recommend this typographical error be fixed the next time the rule is open for revision.

9. Provisions, pursuant to 40 CFR 51.161 th at require opportunity for public comment, as well as the consideration of any comments received during this period in t he final permit

determination. These provisions must also ensure the availability of all information relevant to the proposed permit dur ing the comment period, and allow for a public hearing

upon request.

Discussion : S ection 12.3, subs ection 12.3.8 ( Public Participation ) , requires that ATC issuance be “subject to the public participation requirements in subsection 12.2.16.” subs ection 12.2.16 (Public Participation) contains detailed requirements for public procedures that satisfy the criteria specified

in 51.161. These provisions satisfy the regulatory requirement.

10. For districts which have submitted a minor source NSR permitting program: provisions, pursuant to 40 CFR 51, sections 160 through 164, which contain substantive r equirements

for minor sources. These requirements include public notice, opportunity for

– and

consideration of

– public comment, and the demonstration that a mino r source will not contribute to a violation of any national standard or the area ’s control strategy for

attainment.

Discussion : Section 12.1 contains substantive requirements for minor sources, adequate public notice requirements for all such sources that may significantly affect air quality , and procedures for demonstrating that a minor source will not contribute to a violation of any NAAQS or c ontrol strategy

for attainment

. See, e.g., subsection 12.1.5.3 (Public Participation); subsection 12.1.4.1( c)(1) ( Terms
and Conditions ); subsection 12.1.3.6(a)(3) ( Application Contents ); subsection 12.1.5.1(a)(4) ( Action on Application ), and subsection 12.1.6 ( Revisions to an Existing Minor Source Permit ) ; s ee also our evaluation of Section 12.1 above

. As such, Clark’s program for public participation covers the larger proposed minor sources and modifications and thereby ensures that minor sources will not contribute in any significant way to a violation of any NAAQS or the area’s control strategy for

attainment

.

11. 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 so much of any source's stack height that exceeds good engineering practice.

Discussion : Clark’s PSD program in Section 12.2 contains a provision satisfying this requirement (in

subsection 12.2.7.3 ) , but the NSR program in Section 12.3 does not contain a corresponding requirement

. We propose to disapprove Section 12.3 with respect to this requirement

. This limited disapproval, if finalized, would require Clark to add a provision to Section 12.3 or Section 12.4 that satisfies the requirements of 40 CFR 51.164

.39 1 2

. Provisions, pursuant to 40 CFR 51.165(a)(5)(ii), which require new s ource review for a source or modification which becomes major due to a relaxation in a federally

- enforceable

limit. Such sources and modifications are subject to new source review “ as though construction had not yet commenced. ”

Discussion : S ubs ection 12. 3.7.4 ( Relaxation in Enforceable Limitations ) , states that “At such time that a particular stationary source or modification becomes a major stationary source or major modification solely by virtue of a relaxation in any enforceable limitation which was es tablished after August 7, 1980, on the capacity of the stationary source or modification otherwise to emit a pollutant, then the requirements of subsections 12.3.3 through 12.3.7 shall apply to the stationary source or modification as though construction had not yet commenced on the stationary source or

modification.” This provision satisfies the regulatory requirement.

1 3

. Provisions, pursuant to 40 CFR 51.307(b)(2), which identifies additional requirements for NSR for any new major source or major modif ication, proposing to locate in a nonattainment area, that may have an impact on visibility in any mandatory Class I Federal

Area.

Discussion : S ubs ection12.3.10 requires consultation with the FLM “on a proposed major stationary source or major modificatio n that may impact visibility in any Class I Area, in a ccordance with 40 CFR

51.307.” This provision satisfies the regulatory requirement.

1 4

. Provisions, pursuant to 40 CFR 51.165(a)(1)(iv)(C), which require that fugitive emissions be included in the majo r source applicability determination if the source belongs to one of

the source cate gories listed in this section. Otherwise, fugitives may be excluded from the applicability determination.

Discussion : The definition of the term “major stationary source” in subsection 12.3.2(y), states that “[t]he fugitive emissions of a stationary source shall not be included in determining for any of the purposes of Section 12.3 whether it is a major stationary source , unless the source is a categorical stationary source or belongs to any other stationary source category which, as of August 7, 1980, was being regulated under Section 111 or 112 of the Act.” The definition of “categorical stationary source” in subsection 12.3.2(h) is consistent with the list of source categ ories identified in 40 CFR 51.165(a)(1)(iv)(C). This is acceptable.

The definition of the term “major modification” in subs ection 12.3 .2(x) also requires exclusion of fugitive emissions from the applicability determination unless the major stationary sou rce is a categorical stationary source or belongs to any other stationary source category which, as of August 7, 1980, was being regulated under S ection 111 or 112 of the Act.” Although this language is
consistent with the text of 40 CFR 51.165 ( a

)(

1 )(v) (G) as of July 1, 2010, EPA has administratively stayed this paragraph indefinitely, effective March 30, 2011 (76 FR 17548) (final rule effectuating and extending stay of the final rule entitled "Prevention of Significant Deterioration (PSD) and

Nonattainment New Source Review (NSR): Reconsideration of Inclusion of Fugitive Emissions" (“Fugitive Emissions Rule”) published December 19, 2008). The effect of this administrative stay was

to revert the treatment of fugitive emissions in applicability determinations to the approach that40 applied prior to the Fugitive Emissions Rule, thus requiring that fugitive emissions be included in major modification applicability determinations for all source categories. 76 FR at 17550, 17551. The definition of “major modificatio n” in subsection 12. 3.2 ( x

) is not consistent with this approach to the treatment of fugitive emissions in applicability determinations. We therefore propose to disapprove

this definition. This disapproval, if finalized, would require Clark to revise Sectio n 12. 3 to require that fugitive emissions be included in major modification applicability determinations for all source categories.

1 5

. Provisions, pursuant to section 173(a)(2), which require LAER, for a major source or major modification.

Discussion : The definition of “LAER” in Section 12.3 , subsection 12.3.5 , is consistent with the

Federal definition in CAA section 171 (3)

. S ubs ection 12.3.5.2 requires new major stationary sources to apply LAER for each regulated NSR pollutant that it would have the po tential to emit in significant

amounts. For major modifications, the regulation requires LAER for each regulated NSR pollutant for which there is a significant net emissions increase at the stationary source. This provision satisfies the regulatory require ment.

16. Additional Requirements A pplicable to Ozone Non

- attainment Areas

The general part D NSR permit requirements of title I apply within all nonattainment areas and are supplemented in ozone nonattainment areas by the specific requirements in subpar t 2 of part D. As discussed above, although Clark County was not initially classified under subpart 2 of part D, title I of the Act for the 1997 8

- hour ozone NAAQS, EPA recently classified the area as “marginal” nonattainment for the 1997 8

- hour ozone standard

effective June 1 3 , 2012. 77 FR 28424 (May 14, 2012). Accordingly, the State is now obligated to submit NSR SIP revisions for Clark County meeting the applicable requirement s of subpart 2 of part D, title I of the Act, including an offset ratio of 1.1 to 1 for

NO

x and VOC (see CAA 182(a)(4)) no later than June 13, 2013. W e are not evaluating the submitted NSR rules for compliance with these subpart 2 requirements at this time but

intend to do so following Clark’s submission of the required SIP revisions

.

17. Additional Requirements A pplicable to Particulate Matter ( PM 10 ) Non

- attainment Areas

The general part D NSR permit requirements of title I apply within all nonattainment areas and are supplemented in PM 10 nonattainment areas by the specific requirements in subpart 4 of part D. PM 10 NSR programs for nonattainment areas classified as “serious” must have the following provisions. A discussion of the corresponding Section 12 rule follows each provision

.

1. Definition of the term “major stationary source” consistent with the section 189(b)(3) threshold of 70 tpy for PM 10

.41 Discussion: The definition of “major stationary source” in Section 12. 3 , subsection 12.3.2(y)(1)(A) satisfie s this requirement.

2. Provisions under section 173(a)(1)(A) to ensure that new or modified major stationary

sources obtain an offset ratio of at least 1 to 1.

Discussion: The offset ratio provisions in Section 12.3, subsection 12.3. 6.5 and Table 12.3

- 1 satisfy this requirement.

3. Under section 189(e), requirements applicable to major source s of PM 10 are also applicable to major sources of PM 10 precursors, except where the Administrator determines that such sources do not contribute significantly to PM 10 levels which

exceed the standards in the area.

Discussion: The offset ratio provisions in Section 12.3, subsection 12.3.6.5 and Table 12.3

- 1 satisfy this requirement for major sources of PM 10

. With respect to PM 10 precursors, EPA has previously determine d that major stationary sources of PM 10 precursors do not contribute significantly to PM 10 levels in excess of the NAAQS in Clark County. See 68 FR 2954, 2958 (January 22, 2003). Therefore, Clark is not obligated to require major sources of PM 10 precursors to meet the same requirements as major sources of PM 10

.

4. Provisions to ensure that the significance threshold for a “major modification” is 15 tpy

for PM 10 and, presumptively, 15 tpy for each PM 10 precursor.

Discussion: The definitions in Section 12.3 of “major modification” (subsection 12.3.2(x)) and “significant” (subsection 12.3.2(mm)) satisfy this requirement for PM 10

. As noted above in paragraph 3 , Clark is not obligated to require the same for PM 10 precursors.

Sect ion 12.4

– Authority to Construct Application and Permit Requirements for Part 70 Sources We reviewed this rule for compliance with EPA’s procedural requirements for permit issuance in 40 CFR part 51, subpart I (sections 51.160

– 51.164) , to the extent the se procedures are not addressed by Section 12.1 for minor modifications at major sources, or by Section 12.2 or Section 12.3 for new or modified major stationary sources.

1. 40 CFR 51.160

– Legally enforceable procedures

(a) Each plan must set forth legally enforceable procedures that enable the State or local agency to determine whether the construction or modification of a facility, building, structure or installation or combination of these will result in (1) a violation of applicable portions of t he control strategy; or (2) interference with attainment or maintenance of a national standard in the state in which the proposed source (or modification) is located or in a neighboring State.

Discussion: Section 12.4, subsection 12.4.1.1, prohibits the a ctual construction, modification or42 reconstruction of any “Part 70 source,” including any new or modified major source subject to PSD or NNSR requirements, without an ATC Permit issued by the Control Officer. Subsection 12.4.3.1 specifies the required elem ents of an application for an ATC Permit under Section 12.4, including identification and descriptions of all emission points, process descriptions for all

emissions

- generating activities, the emission rates of all regulated air pollutants, and citations t o and descriptions of all “applicable requirements” as defined in Section 0. See Section 12.4, subsection 12.4.3.1(a). Permits for non

- major Part 70 sources or minor modifications at major sources are governed by nearly identical requirements under subsect ion 12.4.3.2. For new or modified major sources subject to the PSD or NNSR requirements of Section 12.2 or Section 12.3, an application for an ATC Permit must also include all information necessary to process the application in accordance

with those sectio ns. See Section 12.4, subsection 12.4.3.1(b) and (c). These requirements for permit applications in Section 12.4 enable Clark to make the determinations specified in 40 CFR 51.160(a) for all Part 70 sources, including all new or modified major stationary s ources.

(b) Such procedures must include means by which the State or local agency responsible for

final decision

- making on the application for approval to construct or modify will prevent such construction or modification if (1) it will result in a violat ion of applicable portions of the control strategy; or (2) it will interfere with the attainment or maintenance of a national

standard.

Discussion : With respect to new or modified major stationary sources subject to PSD or NNSR, subsection 12.4.1.1(a) pro hibits the actual construction of any new Part 70 source or modification or reconstruction of an existing Part 70 source without an ATC Permit from the Control Officer. See also Section 12.2, subsection 12.2.1.3 (prohibiting actual construction on any new major source or major modification subject to Section 12.2 without an ATC Permit issued in accordance with the requirements of Section 12.4) and Section 12.3, subsection 12.3.1.3 (corresponding prohibition for new and modified sources subject to Section 12 .3). Subsection 12.4.3.1(e) requires that each ATC Permit issued for such a source contain, among other things, all “applicable requirements” (as defined in Section 0) and “[s]uch other conditions as necessary to demonstrate compliance with the requirement s in Section 12.2 or Section 12.3 for construction, subject to those sections.” See subsection 12.4.3.1(e)(10). For any non

- major Part 70 source or minor modification at a major source, paragraph 12.4.3.2(a)(1) requires that the applicant submit a demonstr ation that the new Part 70 source or modification would not cause an exceedance of the ambient air quality standards in Section 11 or an exceedance of ambient air increments specified in Section 12.2, subsection 12.2.3.

Subsection 12.4.3.1(d) requires Clark to initiate public process under Section 12.2.16 on a permit application within one year after the application becomes “complete.” Under subsection 12.2.16(b)(1), Clark may make preliminary determinations to approve, approve with conditions, or disap prove a permit application. Because Section 12.4 authorizes Clark to disapprove a permit application for failure to satisfy applicable requirements, these procedures authorize Clark to prevent

construction or modification of a source where it would result in a violation of an applicable control strategy or interfere with the attainment or maintenance of a NAAQS.

Section 12.4 does not contain a provision that explicitly authorizes Clark to prevent construction if the submitted documents do not adequately m ake the specified demonstrations. We recommend a43 clarification to Section 12.4 to specifically authoriz e Clark to prevent construction if the submitted application materials do not satisfy the applicable requirements

.

(c) The procedures must provide for the submission, by the owner of operator of the building, facility, structure, or installation to be constructed or modified, of such information on (1) the nature and amounts of emissions to be emitted by it or emitted by associated mobile sources; (2) th e location, design, construction, and operation of such facility, building, structure, or installation as may be necessary to permit the State or local agency to make the determination referred to in paragraph (a) of this section.

Discussion : S ection 12.4 , s ubsection 12. 4 .3. 1 ( Application Submission, Processing and Issuance Requirements for Stationary Sources Subject to Sections 12.2 or 12.3 ) and s ubsection 12.4.3.2 ( Application Submission and Processing Requirements for Stationary Sources Not Subject to Section 12.2, Section 12.3

, or subsection 12.4.3.3 )

, specifies the required application submittal information. The information specified is sufficient for Clark to make the determinations referred to in 40 CFR 51.160(a). This is acceptable.

(d) The proced ures must 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.

Discussion : Section 12.4 does not contain a provision to satisfy th is requirement for purposes of regulating new and modified major stationary sources under Section 12.2 and Section 12.3 . EPA is

therefore proposing to disapprove Section 12.4 with respect to this requirement. This limited disapproval, if finalized, would r equire Clark to revise Section 12. 4 (or Sections 12.2 and 12.3, as appropriate) to include a provision meeting the requirement in 40 CFR 51.160(d) and to submit the revised rule to EPA for approval into the Clark County portion of the Nevada SIP.

(e) The procedures must identify types and sizes of facilities, buildings, structures, or installations which will be subject to review under this section. The plan must discuss the basis for determining which facilities will be subject to review.

Discussion : Se ction 12.0 (Applicability, General Requirements and Transition Procedures) generally identifies the types and sizes of stationary sources that are subject to review under each of the

Section 12 rules. See subsection 12.0.1 (Applicability). Additionally, Se ction s 12.1, 12. 2, and 12.3

each contain more specific provisions that identify the types and sizes of stationary sources that are subject to review under those respective rules

. See, e.g., Section 12.1 , subsection 12.1. 0 (Applicability); Section 12.2, subsectio n 12.2.1 (Applicability Procedures) ; and Section 12.3,

subsectio n 12.3. 1 ( Applicability Procedures )

. Finally, S ection 12.4 state s that it applies to construction, modification, or reconstruction activities at “New Part 70 sources” and “Existing Pa rt 70
sources” as those terms are defined in subsection 12.4.2. See subsection 12.4.1.1. Clark’s Minor NSR TSD (at 3

- 3 through 3

- 27 ) discusses Clark’s basis for determining which facilities will be subject

to review under Section 12.1

. These provisions are acceptable.

(f) The procedures must discuss the air quality data and the dispersion or other air quality44 modeling used to meet the requirements of this subpart. (1) All applications of air quality modeling involved in this subpart shall be based on the a pplicable models, data bases, and other requirements specified in appendix W of this part (Guidelines on Air Quality Models). (2) Where an air quality model specified in appendix W of this part (Guideline on Air Quality Models) is inappropriate, the model may be modified or another model substituted. Such a modification or substitution of a model may be made on a case

- by

- case basis or, where appropriate, on a generic basis for a specific State program. Written approval of the EPA must be obtained for any mo dification or substitution. In addition, use of a modified or substituted model must be subject to notice and opportunity for public comment under procedures set forth in 40 CFR 51.102.

Discussion : These requirements are adequately addressed by subsection 12.2.11 in Section 12.2 (Permit Requirements For Major Sources in Attainment Areas) . See discussion of Section 12.2

above.

2. 40 CFR 51.161

– Public availability of information

(a) The legally enforceable procedures in 40 CFR 51.160 must also require t he State or local agency to provide opportunity for public comment on information submitted by owners and operators. The public information must include the agency’s analysis of the effect of construction or modification on ambient air quality, including t he agency’s proposed approval or disapproval.

Discussion : S ection 12.4, subsection 12.4.3.1(d) states that, for any source subject to the requirements of Section 12.2 (PSD) or Section 12.3 (NSR), within one year after the date that an ATC permit application is determined to be complete, the Control Officer must initiate the pu blic participation procedures in subsection 12.2.16. See also Section 12.3, subsection 12.3.8 (Public Participation). These provisions satisfy the public process requirements of 40 CFR 51.161 f or new or modified major stationary sources

. Subsection 12.4.3.2(a) states that, for any permit revision not subject to Section 12.2, Section 12.3, or Section 12.4.3.3, the public participation procedures in

Section 12.1, subsection 12.1.5.3 shall apply. See subsection 12.4.3.2(a)(3). These provisio ns satisfy the public process requirements of 40 CFR 51.161 for minor modifications at existing major stationary sources.

(b) For the purposes of paragraph (a) of this section, opportunity for public comment shall include, as a minimum, (1) Availability for public inspection in at least one location in the area affected of the information submitted by the owner or operator an d of the State or local agency’s analysis of the effect on air quality; (2) A 30

- day period for submittal of public comment; and (3) A notice by prominent advertisement in the area affected of the location of the source information and analysis specified i n paragraph (b)(1) of this section.

Discussion : For both PSD and N onattainment NSR purposes, the public process requirements of 40 CFR 51.161 are satisfied by Section 12.2, subsection 12.2.16 ( Public Participation ), and Section 12.3, subsection 12.3.8 (P ublic Participation). These provisions satisfy the regulatory requirement for45 new or modified major stationary sources

.

(c) Where the 30

- day comment period required in paragraph (b) of this section would conflict with existing requirements for acting on r equests for permission to construct or modify, the State may submit for approval a comment period which is consistent with such existing requirements.

Discussion : This is a discretionary component of a PSD or Nonattainment NSR program that Clark ’s
submitt ed regulations do not contain

. This is acceptable.

(d) A copy of the notice required by paragraph (b) of this section must also be sent to the EPA through the appropriate Regional Office, and to all other State and local air pollution control agencies hav ing jurisdiction in the region in which such new or modified installation will be located. The notice also must be sent to any other agency in the region having responsibility for implementing the procedures required under this subpart. For lead, a copy of the notice is required for all point sources. The definition of point source for lead is given in 40 CFR 51.100(k)(2).

Discussion : For both PSD and Nonattainment NSR purposes, the public process requirements of 40 CFR 51.161 are satisfied by Section 12.2 , subsection 12.2.16 ( Public Participation ), and Section 12.3, subsection 12.3.8 (Public Participation). These provisions satisfy the regulatory requirement for new or modified major stationary sources

.

3. 40 CFR 51.162

– Identification of responsible ag ency

Each plan must identify the State or local agency which will be responsible for meeting the requirements of this subpart in each area of the State. Where such responsibility rests with an agency other than an air pollution control agency, such agency will consult with the appropriate State or local air pollution control agency in carrying out the provisions of this subpart.

Discussion : Nevada law identifies the State Department of Conservation and Natural Resources (DCNR) as the State agency responsible for issuing permits to new or modified sources in all areas of the State of Nevada, except within counties whose populations exceed 100,000. In such counties, Nevada law provides that the applicable permitting agency is the district board of he alth, county board of health or board of county commissioners. See NRS 445B.300 and NRS 445B.500, both of which were approved on August 31, 2006 (71 FR 51766). Clark County is one of only two counties in Nevada whose populations exceed 100,000; and the Cou nty has its own air pollution control agency. Section 12.0 identifies Clark as the agency that will be implementing stationary source permitting requirements in Clark County, including Section 12.1.

The only exception to this basic regulatory structure fo r permitting of sources in Nevada relates to certain power plants that are subject to State, not county, jurisdiction notwithstanding their location

within Clark County . See NRS 445B.500(5), approved into the SIP as noted above ; see also Section 12.0, subs ection 12.0.1 . Thus, the Nevada SIP identifies the State or local agency which is46 responsible for meeting the requirements of 40 CFR part 51, subpart I, in Clark county

.

4. 40 CFR 51.163

– Administrative procedures

The plan must include the administrative procedures, which will be followed in making the determination specified in paragraph (a) of 40 CFR 51.160.

Discussion : Section 12. 4 provides adequate administrative procedures to be followed by Clark in making the determinations specified in 40 CFR 51.160(a), including application requirements, requirements for environmental evaluations, completeness determinations, preliminary findings, public participation, and considerations in the final decision to issue or deny a permit. See, e.g.,

sub section s 12.4.1.1(a)

, 12.4.3.1, and 12.4.3.2

.

5. 40 CFR 51.164

– Stack height procedures

Such procedures must provide that the degree of emission limitation required of any source for control of any air pollutant must not be affected by so much of any so urce’s stack height that exceeds good engineering practice or by any other dispersion technique, except as provided in 40 CFR 51.118(b). Such procedures must provide that before a State issues a permit to a source based on a good engineering practice stack height that exceeds the height allowed by 40 CFR 51.100(ii)(1) or (2), the State must notify the public of the availability of the demonstration study and must provide opportunity for public hearing on it. This section does not require such procedures to restrict in any manner the actual stack height of

any source.

Discussion: Clark’s PSD program in Section 12.2 contains a provision satisfying this requirement (in subsection 12.2.7.3), but neither Section 12.3 nor Section 12.4 contain s a corresponding requirement for the Nonattainment NSR program. We pr opose to disapprove Clark County’s Nonattainment NSR program with respect to this requirement. This limited disapproval, if finalized, would require Clark to add a provision to Section 12 .3 or Section 12.4 that satisfies the requirements

of 40 CFR 51.164

.



### 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 notic e 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 ap plicable 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 February 11, 2010, September 1, 2010, and May 22, 2012 submittals, we find th at DAQ has provided sufficient evidence of public notice and47 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 some specific respects and would relax the SIP in other specific respects. Taken in its entirety, we find that the SIP revision represents a strengthening of Clark County’s minor NSR, PSD, and Nonattainment NSR programs compared to the existing SIP programs that we approved in 1982 and 2004, and that our approval

of the NSR SIP submittal would not interfere wi th any applicable requirement concerning attainment and reasonable further progress (RFP) or any other applicable requirement of the Act.

The most significant deficiencies that we have identified in the submitted NSR rules, as discussed

in detail earlier in this TSD, are generally as follows: (1) the absence of minor NSR provisions that ensure protection of the 2006 PM 2.5 NAAQS and 2008 Lead (Pb) NAAQS; (2) minor NSR applicability provisions that do not cover stationary sources of PM 2.5 ; (3) deficiencies i n the definitions of certain terms used in PSD and Nonattainment NSR (NNSR) applicability determinations; (4) definition of “regulated NSR pollutant” that does not adequately address PSD and NNSR requirements for regulation of condensable particulate matte r; (5) deficiencies in the criteria for assessing the quality (or “integrity”) of emission reduction credits used to satisfy NNSR offset requirements; and (6) the absence of minor NSR or NNSR provisions to ensure that the air quality impacts of stationary sources are not underestimated due to stack heights that exceed good engineering practice or unacceptable air dispersion modeling techniques. We identify these as the “most significant” deficiencies because these are the most likely to affect pollutant

emi ssions within Clark County, compared to other deficiencies that we do not expect would significantly affect emissions levels (e.g., administrative requirements for permit issuance).

Many of these deficiencies are related to requirements that came into eff ect after we last approved Clark County’s NSR programs in 1982 and 2004. For example, minor NSR SIP revisions to implement the 2006 PM 2.5 NAAQS and 2008 Lead (Pb) NAAQS were due in 2009 and 2011, respectively. See CAA 110(a). Similarly, SIP revisions to im plement EPA’s PSD and NNSR requirements for condensable particular matter were due in 2011. See 73 FR 28321 (May 16, 2008). With respect to all of these post

- 2005 requirements, which the existing SIP NSR program does not address, we believe it is reasonabl e to conclude that our approval of the NSR SIP

submittal as a revision to the Nevada SIP would not interfere with any applicable requirement concerning attainment and RFP or any other applicable requirement of the Act, because there is no applicable requirement in the existing SIP program that would be affected by the deficiencies

in the submi tted NSR rules.

As to the remaining deficiencies, we have evaluated these together with the most significant differences between the two NSR programs (SIP

- approved versus the NSR SIP submittal) to evaluate the overall effect that our approval of the NSR SIP submittal migh t have on the stringency of DAQ’s permit programs and the potential air quality impacts of these program revisions. First, certain PSD and NNSR definitions governing applicability determinations in Section 12.2 and Section 12.3 are not as stringent as the corresponding Federal definitions in 40 CFR 51.166 and 51.165, respectively. Second, the offset ratio in Section 12.3 is 1:1, compared to a more stringent48 ratio of 2:1 in the existing SIP NSR program, and the criteria in Section 12.3 for evaluating the

int egrity of emissions reduction credits used to satisfy NNSR offset requirements are not adequate to assure actual emission reductions. Third, the minor NSR program and NNSR program (Sections 12.1, 12.3, and 12.4 to some extent) both lack provisions to ensu re that the air quality impacts of stationary sources are not underestimated due to stack heights that exceed good engineering practice or unacceptable air dispersion modeling techniques. Fourth, DAQ has established public notice thresholds for minor NSR (Section 12.1) that exclude from public review the following types of less

- environmentally significant minor sources: (1) new minor sources with potential emissions of NAAQS pollutants below 50 tons per year (tpy) for CO; 40 tpy for VOCs,

SO 2 , or NO

x ; 15 t py for PM 10 ; and 0.6 tpy for Lead (Pb) ( see subsection 12.1.5.3), and (2) modifications at existing minor sources that result in PTE increases less than 40 tpy for SO 2 ; 35 tpy for CO; 20 tpy for VOC or NO

x ; and 7.5 tpy for PM 10 ( see subsection 12.1.6(a)(7) ). Compare

with SIP Section 12, subsection 12.1.1.1 (requiring preconstruction review for “any new stationary

source” or “modification” without emissions

- based applicability thresholds). Finally, the control standard for minor sources has been changed fr om “Best Available Control Technology” under the SIP minor NSR program to “Reasonably Available Control Technology” under submitted Section 12.1 ( see subsection 12.1.3.6(b), (c)).

With respect to the scope of the NSR program, the deficiencies in the appli cability

- related

definitions in Sections 12.2 and 12.3 and the new de minimis thresholds established in Section 12.1 could potentially reduce the number of new or modified stationary sources that are subject to preconstruction review under these programs a nd thereby relax the NSR program for new and modified sources compared to the SIP

- approved program. As to the minor NSR control standard, the NNSR offset requirements, and the absence of provisions related to stack heights, the submitted NSR rules may res ult in application of less

- stringent control technologies on minor sources (from BACT to RACT), potential under estimations of the air quality impacts of stationary source operations and, with respect to ozone precursor and PM 10 emissions, offset transacti ons that may not achieve adequate emission reductions.

Several significant improvements in the submitted NSR rules should be considered in assessing the overall impact of these potential program relaxations. First, the potential for reduced numbers

of regulated sources is offset to at least some extent by new provisions in Section 12.1 that

establish a five

- year permit term, thereby mandating a regular review of all minor source permit conditions and source operations, and provisions providing that DAQ may re

- open a minor NSR permit at any time for cause. See Minor NSR SIP Submittal , Appendix B: “Technical Requirements.” Second, Section 12.1 requires that each minor NSR permit contain a number of important types of permit terms and conditions which are more specific than required under the SIP NSR program and that strengthen the enforceability of the program

– for example, physica l descriptions of each emission unit, emission limitations that ensure protection of ambient air quality standards, and more clearly defined monitoring, recordkeeping, and reporting requirements modeled on the CAA’s title V operating permit program

. Compar e Section 12.1, subsection 12.1.4.1 (Term and Conditions) with SIP Section 12, subsection 12.8.1.1 (conditions of ATC). Third, Section 12.1 contains important new conditions for issuance of minor NSR permits, such as the requirement to assure compliance w ith all applicable SIP requirements. See49 Section 12.1, subsection 12.1.5.1 (Action on Application) compared to SIP Section 12 (as adopted October 7, 2003), subsection 12.8.2 (ATC issuance requirements). Fourth, both the minor source program in Section 12. 1 and the major source programs in Sections 12.2 and 12.3 rely on several new or revised definitions of key terms that are more consistent with Federal definitions (in CAA 302 and 40 CFR part 51, subpart I) than corresponding definitions in the SIP NSR pro gram. See,

e.g., definition of “potential to emit” in Section 0 11 compared to definition of “total potential to emit” in SIP Section 12 (as adopted October 7, 2003), subsection 12.1.6.1; new definition of

“emission limit” or “emission limitation” in Sectio n 0. Finally, with respect to the difference between BACT and LAER for minor stationary sources in Clark County, supporting information submitted by DAQ indicates that the shift away from the existing BACT standard in the SIP is not likely to affect emiss ions to any significant degree given the ambiguities in the SIP rule which undermined the practical enforceability of this standard, and that the RACT standard in submitted Section 12.1 is expected to be equally effective in controlling emissions at minor sources, if not more so given the enhanced compliance provisions. See Minor NSR TSD at 3

- 20 to 3

- 28 and

Minor NSR SIP Submittal , Appendix B: “Technical Requirements.”

With respect to offset requirements, we note that the SIP NSR program did not require offsets for VOC or NOx because Clark County was not designated nonattainment for any ozone NAAQS at the time when we approved the SIP program in 2004. See Section 59 (Emission Offsets), as adopted October 7, 2003 at Table 59.1.2. The NSR control (LAER) and offset requirements in submitted Section 12.3 therefore ensure greater reductions of ozone precursor emissions compared to the SIP program, which required neither LAER nor offsets for NO

x or VOC. For PM 10 purposes, the SIP NSR program required that major stationary sources (i.e., sources with PTE of 70 tpy or more) obtain PM 10 offsets at a ratio of 2:1, whereas the submitted Section 12.3 requires those same

sources to obtain PM 10 offsets at a ratio of 1:1. See Section 59 (Emission Offsets) (as adopted

Octo ber 7, 2003) at Table 59.1.2 and Section 12.3 (Permit Requirements for Major Sources in Nonattainment Areas) (as adopted May 18, 2010) at Table 12.3

- 1. This relaxation in the offset

ratio for PM 10 sources applies only to stationary sources locating within the boundaries of the PM 10 nonattainment area in the Las Vegas planning area (hydrographic area #212), and appears to be offset by the overall strengthening in the NSR program, as discussed above with respect to both major and minor sources throughout Clar k County. Significantly

, the submitted Section 12.2 includes new PSD provisions to regulate new or modified major stationary sources of greenhouse gases (GHGs) and PM 2.5 , both of which are entirely unregulated under the existing SIP PSD program. In additio n, both Section 12.2 and Section 12.3 satisfy the requirements of EPA’s 2002 NSR Reform rules, with limited exceptions.

In sum, the new and revised provisions in the submitted NSR rules enable DAQ to review source operations on a more regular basis; require DAQ to make specific determinations related to air

11 Section 12.1 establishes emission

- based applicability thresholds based on a definition of “potential to emit” in submitted Section 0 that is generally equivalent to EPA’s defi nition of this term in 40 CFR 51.165 and 51.166. The SIP NSR program in Section 12 (as adopted October 7, 2003), contains applicability provisions based on a definition of “total potential to emit” that is generally more expansive but allows, on the other hand, for certain engines categorized as “special mobile equipment” to be inappropriately exempt from the calculation of PTE (see SIP Section 12, subsection 12.1.6.1).50 quality impacts and applicable SIP requirements as part of permit issuance; improve the enforceability of the NSR program through the establishment of more detailed compliance requirements and impr oved definitions of important terms; establish NNSR requirements for ozone precursor emissions that were not required under the existing SIP program; and establish new PSD provisions for the regulation of GHG and PM 2.5 emission sources. We find that, on

b alance, these NSR program improvements outweigh the potential relaxations discussed above compared to the existing SIP program. In addition, we are unaware of any reliance by DAQ on the continuation of any aspect of the permit

- related rules in the Clark Co unty portion of the Nevada SIP for the purpose of continued attainment or maintenance of the NAAQS. Given all these considerations, we propose to conclude that our approval of these updated NSR regulations into the Nevada SIP would not interfere with any applicable requirement concerning attainment and RFP or any other applicable requirement of the Act. 12

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 N ovember 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 believ e 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.

E

PA , 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 two nonattainment areas in Clark County (for

the 1997 8

- hour ozone NAAQS and the PM 10 NAAQS) for the following reasons. For ozone purposes, the pre

- 1990 SIP NSR program contained no offset requirement because Clark County was not designated nonattainment for any ozone NAAQS at that time. See Section 15.14.4.3 (as adopted 1981). The NSR control (LAER) and offset requirements in submitted Section 12.3 therefore ensure greater reduct ions of ozone precursor emissions compared to the pre

- 1990

12 With respect to the two NAAQS for which portions of Clark County remain designated nonattainment (PM 10 and

1997 8

- hour ozone), EPA has recently determined based on ambient air monitoring data that Clark County is attaining

both of these standards. See 75 FR 45485 (August 3, 2010) (Determination of Attainment for PM 10 for the Las Vegas Valley Nonattainment Area) and 76 FR 17343 (March 29, 2011) (Determination of Attainment for the Clark County

1997 8

- Hour Ozone Nonattainment Area).51 program, which required neither LAER nor offsets for NO

x or VOC. For PM 10 purposes, the

pre

- 1990 NSR program required that PM 10 sources with PTE of 25 tpy or more obtain PM 10 offsets

at a ratio of 1:1, whereas the submitted Section 12.3 requires sources with PTE of 70 tpy or more to

obtain PM 10 offsets at that same ratio. Compare Section 15.14.4.3 (as adopted 1981) with Section 12.3 (Permit Requirements for Major Sources in Nonattainment Areas) (as adopted May 18, 2010)

at Table 12.3

- 1. We believe, however, that this relaxation in the applicability threshold for PM 10 offsets is outweighed by the improvements in the applicability provisions and compliance requirements of both the minor NSR program (Se ction 12.1), which applies throughout Clark County including the Las Vegas Valley, and the Nonattainment NSR program (Section 12.3), as discussed above. We therefore conclude that the submitted NSR program will provide for equivalent or greater emissions r eductions as the existing SIP NSR program for the two applicable nonattainment pollutants, ozone and PM 10

.

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

section 193 of the Act.



### Recommendations for Rule Revisions

We discuss below rule revisions or clarifications that are not currently bases for disapproval but that we recommend DAQ adopt at its earliest opportunity.

(1) Section 0 (Definitions): The definition of “potential to emit” generally tracks EPA’s definition of this term in 40 CFR 51.165(a)(1)(iii) and 40 CFR 51.166(b)(4) but uses the phrase “enforceable as a practical matter” in lieu of “federally enforceable.” EPA generally allows for recognition of limits that are “enforceable as a practical matt er” provided the relevant rule provides criteria by which a limit will be judged to be “practically enforceable” or “enforceable as a practical matter.” Consistent with these principles, we recommend that DAQ revise the definition of “potential to emit” in Section 0 to include such criteria or add a new definition for the term “enforceable as a practical matter” in Section 0. We note that the criteria provided in Section 12.1, subsection 12.1.7, for establishing voluntarily accepted emission

limitations and standards that are “enforceable as a practical matter” are acceptable and may be used in the Section 0 definition of “potential to emit” as well.

(2) Section 12.1 (Minor NSR): EPA revised the NAAQS for NO 2 and SO 2 in 2010, and minor NSR SIP revisions to impl ement these standards are due January 22, 2013 and June 2, 2013, respectively. See 75 FR 6474 (February 9, 2010) (final rule establishing new 1

- hour

standard for NO 2 ) and 75 FR 35520 (June 22, 2010) (final rule establishing new 1

- hour

standard for SO 2 ). We recommend that DAQ revise its definition of “ambient air quality standards” in Section 11 to include these additional NAAQS and to submit the revised rule as a SIP revision prior to these upcoming deadlines. Alternatively, we recommend that DAQ revise

Sec tion 12.1, subsection 12.1.4.1(c), to reference the “National Ambient Air Quality Standards” instead of “ambient air quality standards” to ensure protection of all of the NAAQS52 in the issuance of permits for new or modified minor sources, consistent with t he requirements of 40 CFR 160(a).

(3) Section 12.1 (Minor NSR): Under subsection 12.1.6(d) (“Changes that can be made with prior notice”), we recommend that Clark revise subparagraph (d)(5) to clarify that this provision

does not cover any change that may inc rease the source’s PTE by “significant” amounts. Although the rule currently provides that any change that triggers a new applicable requirement does not qualify for this procedure, it should be clear in the rule that where a change may potentially increas e the source’s PTE by significant amounts, the source should submit an application for a significant permit revision. This would ensure that DAQ can evaluate the potential emissions impacts of the change before the source proceeds with

construction. Additi onally, we note that the reference to paragraph (2)(E) in subsection 12.1.6(b) appears to be a typographical error and should be corrected by replacing (E) with (D).

(4) Section 12.2 (PSD): In DAQ’s definition of “baseline actual emissions” in subsection

12.2 .2(c), we recommend that subparagraph (1)(B)(i) be relabeled as a separate paragraph ((1)(C) or(1)( E)), as it is not appropriate to characterize this provision as a subset of paragraph (1)(B). See 40 CFR 51.166(47)(ii). Other provisions that cross

- referen ce subparagraph (1)(B)(i) will then need to be revised accordingly. For example, paragraph (1)(D) will need to be revised to include a reference to the new paragraph (current subparagraph (1)(B)(i), relabeled as appropriate). See 40 CFR 51.166(47)(ii)( e ).

(5) Section 12.2 (PSD): Because NDEP shares PSD increment

- tracking responsibility with Clark for baseline areas inside Clark County, we recommend that Clark revise subsection 12.2.15.1 to provide for copies of permit applications to also be sent to NDEP. NDEP coordination should also occur prior to public review to ensure proper analysis of increment consumption.

(6) Section 12.2 (PSD): Subsection 12.2.19.2(a) currently states that the listed definitions apply and that “[w]hen a term is not defined in these parag raphs, it shall have the meaning given in Section 0, Section 12.4 or the Act.” We recommend that Clark revise subsection 12.2.19.2(a) to clarify the applicable definitions. To the extent that Clark intended for the definitions provided in Section 12.2 (sub section 12.2.2) to apply before any of the other cited provisions, we recommend clarifying the provision accordingly.

(7) Section 12.3 (Nonattainment NSR): In Table 12.3

- 1 of Section 12.3, which provides the offset ratios applicable in the nonattainment portions of Clark County, the phrase “nonattainment without designation” is confusing as any nonattainment area is, by definition, designated. As part of its rulemaking to incorporate the 1.1 to 1 offset ratio required pursuant to EPA’s subpart

2 classific ation of the Las Vegas Valley area for the 1997 8

- hour ozone NAAQS, we recommend that DAQ also revise Table 12.3

- 1 to clarify that the revised offset ratio for NO

x and VOC applies throughout the “marginal” ozone nonattainment area in Clark County.

– for

ex ample, by replacing "Nonattainment without Designation" with "Marginal Nonattainment Area" and providing the required subpart 2 offset ratio of 1.1 to 1.53 

### EPA’s Proposed Action

Pursuant to section 110(k)(3) of the Act, we are proposing a limited approval and limited disapproval of the submitted NSR rules. We are proposing to approve the submitted NSR rules based on our determination that, for the most part, the rules satisfy the applicable statutory and regulatory provisions governing regulation of statio nary 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 replacement or 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. Simultaneously, we are proposing a lim ited disapproval of specified provisions in the submitted NSR rules because they do not fully satisfy the applicable CAA and regulatory requirements, as summarized below.

With respect to the Minor NSR program, Section 12.1 does not provide a means for det ermining whether the construction or modification of a stationary source will result in a violation of applicable portions of the control strategy or interference with attainment or maintenance of the

2006 24

- hour PM 2.5 NAAQS and the 2008 Lead NAAQS, becau se the rule references an outdated definition of “ambient air quality standards”; contains inappropriate language regarding federal enforceability of permits issued under Section 12.1; does not contain provisions to ensure 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; provides inappropriate exemptions for sources identified in a separate rule that is not SIP

- approved (Section 12.5); do es not contain applicability provisions that cover sources of PM 2.5 or PM 2.5 precursor emissions; and does not contain 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 un acceptable air dispersion modeling techniques.

With respect to the PSD permit program, Section 12.2 contains definitions for the terms “allowable emissions,” “baseline actual emissions,” “net emissions increase,” “major

modi fication,” and “regulated NSR pollutant” that are not entirely consistent with EPA’s definitions in 40 CFR 51.166; contain a provision governing adjustment of PALs to incorporate requirements that become effective during the term of a PAL that is not entir ely consistent with

EPA’s requirements; and does not contain, either in Section 12.2 or in Section 12.4, a provision addressing the requirement in 40 CFR 51.160(d) to provide that approval of any construction or modification must not affect the responsibil ity on the owner or operator to comply with applicable portions of the control strategy.

Finally, with respect to the Nonattainment NSR program, Section 12.3 contains provisions governing offsets and calculation of emission reduction credits that do not e nsure the integrity of offset calculations and that reference a separate rule that is not SIP

- approved (Section 12.7) for important criteria governing these calculations; contains definitions for the terms “baseline actual54 emissions,” “major modification,” and “regulated NSR pollutant” that are not entirely consistent with EPA’s definitions in 40 CFR 51.165; allows for interpollutant trades between certain pollutants without satisfying EPA’s criteria for approval of such trades; does not contain 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 un acceptable air dispersion modeling techniques; and does not contain, either in Section 12.3 or in S ection 12.4, a provision addressing 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.