[Federal Register Volume 69, Number 106 (Wednesday, June 2, 2004)]
[Proposed Rules]
[Pages 31056-31068]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-12412]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[NV052-0079; FRL-7669-3]


Approval and Promulgation of Implementation Plans; New Source 
Review; State of Nevada, Clark County Department of Air Quality 
Management

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This action is a proposed partial approval and partial 
disapproval of several rules that were submitted as a revision of the 
Clark County portion of the Nevada State Implementation Plan (SIP). We 
had approved a similar version of these rules into the Nevada SIP in 
1999. See 64 FR 25210 (May 11, 1999). Our approval was appealed to the 
U.S. Court of Appeals for the Ninth Circuit, which vacated the 1999 
approval and remanded our approval of the rules for further 
consideration. See Hall v. EPA, 273 F.3d 1146 (9th Cir. 2001). This 
proposed partial approval and partial disapproval of the rules for the 
reasons discussed more fully below responds to the issues raised in the 
court's remand.
    The rules at issue in this proposed action were adopted by the 
Clark County Department of Air Quality Management for issuing permits 
for new or modified stationary sources in Clark County to comply with 
the applicable permitting requirements under parts C and D of title I 
of the Clean Air Act as amended in 1990 to prevent significant 
deterioration in attainment areas and to attain the National Ambient 
Air Quality Standards in nonattainment areas. EPA is also proposing to 
approve as a revision to the Nevada SIP a State regulation prohibiting 
the construction of major new or modified sources under exclusive State 
jurisdiction in the nonattainment areas within Clark County. The 
intended effect of this proposed action is to ensure that the Clark 
County Department of Air Quality Management's permitting rules are 
consistent with Ninth Circuit's ruling in Hall v. EPA and with the 
requirements of the Clean Air Act, as amended in 1990. EPA is also 
proposing to amend the appropriate section of the Code of Federal 
Regulations to reflect the successful court challenge to an EPA 
approval of previous versions of these local rules. Lastly, under 
section 110(k)(6) of the Act, EPA is proposing to correct or clarify 
certain previous final rulemaking actions taken by EPA on revisions to 
the Clark County portion of the Nevada SIP. EPA is taking comments on 
this proposal and plans to follow with a final action.

DATES: Comments on this proposed rule must be received in writing by 
July 2, 2004.

ADDRESSES: Written comments on this action should be addressed to 
Gerardo Rios, Chief, Permits Office, Air Division (AIR-3), EPA Region 
IX, 75 Hawthorne Street, San Francisco, California, 94105.
    You can inspect copies of the State's submittals, EPA's technical 
support documents (TSDs), and other supporting documentation relevant 
to this action, during normal business hours at Air Division, EPA 
Region IX, 75 Hawthorne Street, San Francisco, California 94105.
    You may also see copies of the State's two submittals at the Nevada 
Division of Environmental Protection, 333 W. Nye Lane, Room 138, Carson 
City, Nevada 89706. The State's submittal of DAQM's amended rules is 
available at the Clark County Department of Air Quality Management, 500 
S. Grand Central Parkway, Las Vegas, Nevada 89155.

FOR FURTHER INFORMATION CONTACT: Roger Kohn, EPA Region IX, Air 
Division, Permits Office (AIR-3), at (415) 972-3973 or 
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us'' and 
``our'' refer to EPA.

Table of Contents

I. Evaluation of Clark County New Source Review Rules
    A. The State's Submittal
    B. EPA's Evaluation and Action
II. Corrections to, or Clarification of, the Clark County Portion of 
Nevada State Implementation Plan
III. Proposed Action and Public Comment
IV. Statutory and Executive Order Reviews

I. Evaluation of Clark County New Source Review Rules

A. The State's Submittal

    Table 1 lists the rules addressed by this proposal with the dates 
that they were adopted by the local air agency, the Clark County 
Department of Air Quality Management (DAQM), or were adopted by the 
State Environmental

[[Page 31057]]

Commission (SEC), and submitted by the State air agency, the Nevada 
Division of Environmental Protection (NDEP), to EPA as revisions to the 
Nevada State Implementation Plan (SIP).

                                            Table 1.--Submitted Rules
----------------------------------------------------------------------------------------------------------------
              Agency                     Rule               Rule title           Adopted     Submitted
----------------------------------------------------------------------------------------------------------------
DAQM.............................  0........................  Definitions.............     10/07/03     10/23/03
DAQM.............................  11.......................  Ambient Air Quality          10/07/03     10/23/03
                                                               Standards.
DAQM.............................  12.......................  Preconstruction Review       10/07/03     10/23/03
                                                               for New or Modified
                                                               Stationary Sources.
DAQM.............................  52.8.....................  Gasoline Dispensing          10/07/03     10/23/03
                                                               Facilities--Section 52
                                                               Offset Program.
DAQM.............................  58.......................  Emission Reduction           10/07/03     10/23/03
                                                               Credits.
DAQM.............................  59.......................  Emission Offsets........     10/07/03     10/23/03
SEC..............................  NAC 445B. 22083..........  Construction, major          03/29/94     11/20/03
                                                               modification or
                                                               relocation of plants to
                                                               generate electricity
                                                               using steam produced by
                                                               burning of fossil fuels.
----------------------------------------------------------------------------------------------------------------

    On November 18, 2003, the submittal containing DAQM's rules was 
found to meet the completeness criteria in 40 CFR part 51, appendix V, 
which must be met before formal EPA review.
    DAQM's predecessor agency (the Clark County Health District) 
adopted earlier versions of the Clark County New Source Review (NSR) 
rules, then numbered section 1 (Definitions), section 11 (Ambient Air 
Quality Standards), and section 15 (Source Registration), at various 
times from 1979 through 1981, which we approved into the Clark County 
portion of the Nevada SIP at various times in 1981 and 1982. 
Specifically, we approved different defined terms of section 1 
(Definitions) into the applicable SIP on three occasions in 1981 and 
1982. See 46 FR 21758 (April 14, 1981), 46 FR 43141 (August 27, 1981), 
and 47 FR 26620 (June 21, 1982). We approved section 11 (Ambient Air 
Quality Standards) into the applicable SIP on August 27, 1981 (46 FR 
43141). We approved different subsections of section 15 (Source 
Registration) into the applicable SIP on two occasions in 1981 and 
1982. See 46 FR 21758 (April 14, 1981) and 47 FR 26620 (June 21, 1982).
    Pursuant to the Clean Air Act Amendments of 1990 (CAA or Act), 
Clark County revised their NSR rules, then contained in local sections 
0, 12, and 58, and in 1995, EPA proposed to approve with a contingency, 
and disapprove in the alternative, these revised rules into the SIP. 
See 60 FR 38777 (July 28, 1995). Following our 1995 proposed action, 
Clark County revised their NSR rules (sections 0, 12, and 58) to 
address the contingency identified by EPA and re-submitted them via 
NDEP to EPA. In 1999, we found the contingency to have been satisfied 
and approved the revised NSR rules into the SIP. See 64 FR 25210 (May 
11, 1999). Our 1999 final action was challenged, and in 2001, the U.S. 
Court of Appeals for the Ninth Circuit vacated our approval of Clark 
County's NSR rules (specifically, sections 0, 12, and 58, as submitted 
and acted on in 1999). See Hall v. EPA, 273 F.3d 1146 (9th Cir. 2001).
    The court vacated our approval on the grounds that EPA did not have 
an adequate basis under section 110(l) of the Act to conclude that 
substitution (i.e., replacement or supercession) of the pre-existing 
NSR SIP rules (sections 1, 11, and 15) with the new NSR rules (sections 
0, 12, and 58) would not interfere with attainment of the NAAQS for 
carbon monoxide (CO) and particulate matter with an aerodynamic 
diameter less than or equal to a nominal 10 micrometers (PM-10) (i.e., 
the two pollutants for which a sub-region of Clark County, Las Vegas 
Valley, is designated nonattainment) by the applicable attainment 
deadlines. In recognition of this ruling, we are proposing to delete 
and reserve the paragraphs in section 1470 (``Identification of plan'') 
of 40 CFR part 52, subpart DD (Nevada) that codified our 1999 approval 
(i.e., 40 CFR 52.1470(c)(37) and (38)) to clarify that, until the 
effective date of EPA's final approval of the submitted NSR rules into 
the SIP, sections 1, 11, and 15 (as approved by EPA in 1981 and 1982) 
represent the applicable SIP NSR rules in Clark County.
    Subsequently, Clark County adopted revised NSR rules (then 
contained in local sections 0, 11, 12, 58, and 59) on December 4, 2001. 
This version of the Clark County NSR rules, excluding section 11, was 
submitted to EPA by NDEP by letter dated February 25, 2003. We did not 
take action on that submittal, which has been superceded by DAQM's 
adoption of additional revisions to the Clark County NSR rules (now 
expanded to include section 52, subsection 52.8, as well as sections 0, 
11, 12, 58 and 59) on October 7, 2003 and NDEP's re-submittal to EPA 
dated October 23, 2003. In this notice, we refer to this latest 
submittal of the DAQM NSR rules (sections 0, 11, 12, 52.8, 58, and 59) 
as the ``DAQM NSR submittal.'' While we can act on only the most 
recently submitted version, we have reviewed materials provided with 
previous submittals. The TSD provides additional background information 
on the various NSR SIP submittals for Clark County.
    EPA revised its federal regulations implementing Parts C and D of 
the CAA on December 31, 2002, and those revisions became effective on 
March 3, 2003. Because Clark County had submitted a version of its 
revised NSR rules to us specifically in response to the court's 2001 
ruling in Hall v. EPA, EPA is now evaluating DAQM's NSR submittal based 
on the federal NSR regulations that were in effect at the time of the 
ruling in Hall v. EPA (prior to December 31, 2002). This proposed 
rulemaking, therefore, does not establish any precedent for evaluating 
whether a proposed NSR SIP fulfills the requirements of the revised NSR 
regulations that were published December 31, 2002. The evaluation in 
this proposed rulemaking of DAQM's NSR submittal is limited to whether 
the submittal meets the requirements of the federal NSR regulations as 
they existed at the time of the ruling in Hall v. EPA, prior to 
revision on December 31, 2002.
    There is no previous version of Nevada Administrative Code (NAC) 
445B.22083 (Construction, major modification or relocation of plants to 
generate electricity using steam produced by burning of fossil fuels) 
approved, or submitted for approval, into the Nevada SIP.
    Submitted DAQM sections 0, 11, 12, 52.8, 58, and 59 represent a 
comprehensive revision to Clark County's NSR program and are intended 
to satisfy the requirements under both part C (prevention of 
significant deterioration)(PSD) and part D (nonattainment new source 
review) of

[[Page 31058]]

title I of the Act as those parts relate to permitting of major new 
sources or major modifications as well as provide for a minor source 
permitting program as required under section 110(a)(2)(C) of the Act. 
Submitted DAQM section 0 (Definitions) consists of definitions of all 
terms relating to new sources and modifications to existing sources of 
air pollution. As is the case for existing SIP section 1 (Definitions), 
DAQM section 0 also contains numerous definitions of terms used in 
prohibitory rules not related to NSR. Some of these prohibitory rules 
are already approved into the SIP (e.g., SIP section 53 (Oxygenated 
Gasoline Program)) while others are expected to be approved into the 
SIP in the near future (e.g., DAQM section 54 (Cleaner Burning 
Gasoline) and DAQM sections 90 through 94 (related to various fugitive 
dust sources)). Therefore, with respect to submitted DAQM section 0, we 
are proposing to approve the entire rule, not just those definitions 
related to NSR, however, as explained later in this notice, we are 
proposing to retain in the SIP certain definitions from existing SIP 
section 1 because they are needed for various existing SIP rules 
unaffected by this action.
    DAQM section 11 sets forth the current national ambient air quality 
standards (NAAQS). DAQM section 12 sets forth the source permitting 
requirements, including those related to applicability, control 
technology (i.e., Lowest Achievable Emission Rate (LAER) or Best 
Available Control Technology (BACT)), offsets, and public notice. DAQM 
subsection 52.8 contains offset requirements for new or modified 
gasoline dispensing facilities whose annual through-put is more than 
3.6 million gallons of gasoline per year. DAQM section 58 establishes 
procedures for the creation, banking, and use of emission reduction 
credits, and DAQM section 59 establishes offset requirements for new or 
modified sources. NAC 445B.22083 is a State regulation prohibiting the 
construction of major new or modified sources under exclusive State 
jurisdiction in the nonattainment areas within Clark County. The TSD 
has more information about these rules.

B. EPA's Evaluation and Action

SIP Revision Procedural Requirements
    The Act requires States to observe certain procedural requirements 
in developing implementation plans and plan revisions for submission to 
EPA. Sections 110(a)(2) and 110(l) of the Act provide that each 
implementation plan or revision submitted by a State must be adopted 
after reasonable notice and public hearing. Section 172(c)(7) of the 
Act provides that plan provisions for nonattainment areas shall meet 
the applicable provisions of section 110(a)(2).
    DAQM held a public hearing on October 7, 2003 to entertain public 
comment on revisions to the following local air pollution regulations: 
sections 0, 11, 12, 52.8, 58 and 59. Notice for that hearing was 
provided by advertisement in a newspaper of general circulation in the 
applicable area on three separate days in September 2003. On October 7, 
2003, the amended rules were adopted by DAQM and submitted to the 
State. On October 23, NDEP submitted the amended rules to EPA for 
approval as a revision to the Nevada SIP. We find that this process 
satisfies the procedural requirements under sections 110(a)(2), 110(l) 
and 172(c)(7) of the Act.
    With respect to NAC 445B.22083, the Nevada SEC held a public 
hearing on March 3, 1994 to entertain public comment on the submitted 
rule. Notice for that hearing was provided by advertisement in a 
newspaper of general circulation in the applicable area on three 
separate days in February 1994. On March 3, 1994, the Nevada SEC 
adopted the submitted rule, which was subsequently renumbered in 2002 
to its current codification as NAC 445B.22083. On November 20, 2003, 
NDEP submitted NAC 445B.22083 to EPA for approval as a revision to the 
Nevada SIP. We find that this process satisfies the procedural 
requirements under sections 110(a)(2), 110(l), and 172(c)(7) of the 
Act.
General Nonattainment and PSD Requirements
    We have evaluated DAQM's NSR SIP submittal described above against 
the applicable requirements of section 110 and parts C and D of (title 
I) of the Act and the implementing regulations at 40 CFR 51.160 through 
51.166 (July 1, 2002). We also relied upon the following materials in 
the review of this submittal: General Preamble for the Implementation 
of Title I of the Clean Air Act Amendments of 1990 (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.
    We note that, on December 31, 2002, EPA published a final notice 
revising regulations governing NSR programs (``Federal NSR 
regulations'') mandated by parts C and D of title I of the Act. See 67 
FR 80186. These revisions include changes in the NSR applicability 
requirements for modifications to allow sources more flexibility to 
respond to rapidly changing markets and to plan for future investments 
in pollution control and prevention technologies. We selected March 3, 
2003 as the effective date for our revision to the Federal NSR 
regulations. Normally, we would be evaluating the Clark County NSR SIP 
submittal on the basis of the current Federal NSR regulations, which 
would include these most recent revisions, but in light of the unusual 
circumstances surrounding EPA's review process for the Clark County NSR 
rules, i.e., court vacature of a fully-approved set of NSR rules, we 
have not evaluated the submitted NSR rules for consistency with the 
revised Federal NSR regulations but have evaluated them instead against 
the Federal NSR regulations that were in effect when the rules were 
being revised to address issues raised by EPA in the wake of the Hall 
decision. Like other State and local agencies, Clark County must adopt 
and submit revisions to its SIP-approved NSR rules implementing the 
minimum program requirements set forth in the revised Federal NSR 
regulations no later than January 2, 2006. See 67 FR 80186, at 80240 
(December 31, 2002). Given this approach to our evaluation of the DAQM 
NSR submittal, the reader should refer to the 2002 version of 40 CFR 
parts 51 and 52 (revised as of July 1, 2002) where citations are made 
herein to the those parts of the CFR.
Nonattainment NSR Requirements
    The Act requires all States with nonattainment areas to submit, by 
November 15, 1992, nonattainment NSR provisions that comply with part D 
(of title I) of the Act and the related implementing regulations. The 
Las Vegas Valley (hydrographic area 212), a sub-region within 
Clark County, was designated as a nonattainment area for both the 
carbon monoxide (CO) and particulate matter (PM-10) NAAQS under the 
Clean Air Act Amendments of 1990, and thus, the nonattainment NSR 
requirements apply to that area. Las Vegas Valley is currently 
classified as a ``serious'' nonattainment area for both the CO and PM-
10 NAAQS. See 40 CFR 81.329.
    First, it should be noted that, pursuant to State law, the State of 
Nevada, not a local air or health district, has jurisdiction over 
plants which generate electricity by using steam produced by the 
burning of fossil fuel within the State of Nevada. The applicable State 
law, now codified in Nevada Revised Statutes (NRS)

[[Page 31059]]

445B.500, was approved by EPA as a SIP revision in 1980 as NRS 
445.546(4). See 45 FR 46384 (July 10, 1980). Thus, within Clark County, 
the State, not DAQM, has jurisdiction over such plants that are 
located, or that will be constructed, in that county (including the 
nonattainment area). This exclusion is reflected in submitted DAQM 
section 12, subsection 12.1.3.2.
    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 nonattainment area 
within Clark County. Normally, because NDEP has jurisdiction over a 
particular category of stationary sources in a nonattainment area 
(i.e., Las Vegas Valley), the State would be required to adopt and 
submit a Nonattainment NSR program for new major sources or major 
modifications within the applicable source category in the 
nonattainment area. However, EPA is not requiring the State to submit 
Nonattainment NSR rules for Las Vegas Valley because the Nevada SEC 
adopted a regulation (NAC 445B.22083) that prohibits new power plants 
or major modifications to existing power plants under State 
jurisdiction within the Las Vegas Valley nonattainment area, and NDEP 
has submitted that regulation to EPA as a revision to the SIP. We 
propose to approve this regulation into the Nevada SIP to resolve the 
regulatory gap that would otherwise exist in connection with NSR for 
sources under NDEP jurisdiction within the nonattainment area of Clark 
County.
    With respect to the DAQM NSR submittal, we have concluded that it 
meets the applicable Nonattainment NSR requirements on the basis of the 
following findings:
    1. The DAQM NSR submittal provides for calculation of emissions 
offsets based on the same emissions baseline used in the demonstration 
of reasonable further progress as required by section 173(a)(1)(A) of 
the Act (see DAQM section 0, ``emission reduction credit'' and 
``baseline emissions''), provides for emissions offsets to be obtained 
when the construction permit for a new or modified source is issued and 
to be in effect by the time the new or modified source commences 
operation as required by section 173(c)(1) of the Act (see DAQM section 
59, subsection 59.4.2.6), provides for emissions increases from new 
major sources or major modifications to be offset by real reductions in 
actual emissions as required by section 173(c)(1) of the Act (see DAQM 
section 0, ``emission reduction credit (ERC),'' and specifically 
paragraph (b) of that definition: ``Section 58 emission reduction 
credit'', and DAQM section 59, subsection 59.1.5), prohibits emissions 
reductions otherwise required by the Act from being used for NSR offset 
purposes as required by section 173(c)(2) of the Act (see DAQM section 
0, ``surplus,'' and DAQM section 59, subsection 59.4.2.1), and provides 
for appropriate limitations on ``prior shutdown'' emission reduction 
credits as required in 40 CFR 51.165(a)(3)(ii)(C) (see DAQM section 58, 
subsection 58.3.2.5.3).
    2. The DAQM NSR submittal provides for an analysis of alternative 
sites, sizes, production processes, and environmental control 
techniques as a prerequisite to issuing construction permits to new 
major sources or major modifications of nonattainment pollutants as 
required by section 173(a)(5) of the Act (see DAQM section 12, 
subsection 12.1.4.1(k)), provides for a definition of ``stationary 
source'' that includes certain internal combustion engines as required 
by section 302(z) of the Act (see DAQM section 0, ``stationary 
source''), and provides for a demonstration that all other major 
stationary sources under the same ownership as the proposed source are 
in compliance with the Act as required by section 173(a)(3) of the Act 
(see DAQM section 12, subsection 12.8.2(b)).
    3. The DAQM NSR submittal provides for opportunities for, and due 
consideration of, public comment as required by 40 CFR 51.161 and 
provides for substantive requirements for new or modified minor sources 
as required in 40 CFR 51.160 through 51.164 (see the pollutant-specific 
requirements in DAQM section 12, subsection 12.2 and the notice and 
public hearing requirements in DAQM section 12, subsections 12.3.2, 
12.3.3, and 12.3.4).
    4. The DAQM NSR submittal provides for appropriate stack height 
limitations as required in 40 CFR 51.118(a) (see DAQM section 12, 
subsection 12.5.4), provides for appropriate review of a source or 
modification which becomes major due to a relaxation in a federally-
enforceable limit as required in 40 CFR 51.165(a)(5)(ii) (see DAQM 
section 0, ``major modification'' and ``stationary source''), provides 
for additional requirements for any new major source or major 
modification that may have an impact on visibility in any mandatory 
Class I Federal Area as required in 40 CFR 51.307(b)(2) (see DAQM 
section 12, subsection 12.12), provides for appropriate consideration 
of fugitive emissions as required in 40 CFR 51.165(a)(1)(iv)(C) (see 
DAQM section 0, paragraph (b)(1) under ``stationary source''), and 
provides for application of the Lowest Achievable Emission Rate (LAER) 
on all new major sources and major modifications of nonattainment 
pollutants as required in section 173(a)(2) of the Act (see DAQM 
section 12, subsections 12.2.2.2, 12.2.4.2, and 12.2.23.2 for PM-10, 
and subsections 12.2.7.3 and 12.2.9.3 for CO).
    5. The DAQM NSR submittal provides for, as required under subpart 3 
of part D of title I of the Act, appropriate thresholds for major 
sources and major modifications in ``serious'' CO nonattainment areas 
(see DAQM section 0, ``stationary source'' and ``major modification'') 
in which stationary sources are not significant contributors to ambient 
CO levels (see EPA's proposed finding related to the impact of 
stationary sources on ambient CO levels in Las Vegas Valley in 68 FR 
4141, at 4154 (January 28, 2003)), and provides for an appropriate 
offset ratio (see DAQM section 59, subsection 59.1.4, table 59.1.2).
    6. The DAQM NSR submittal provides for, as required under subpart 4 
of part D of title I of the Act, appropriate thresholds for major 
sources and major modifications in ``serious'' PM-10 nonattainment 
areas (see DAQM section 0, ``stationary source'' and ``major 
modification'') in which PM-10 precursors (e.g., oxides of nitrogen, 
sulfur dioxide, and volatile organic compounds) do not contribute 
significantly to PM-10 levels which exceed the standards in the area 
(see EPA's proposed finding related to the impact of PM-10 precursors 
in Las Vegas Valley in 68 FR 2954, at 2958 (January 22, 2003)), and 
provides for an appropriate offset ratio (see DAQM section 59, 
subsection 59.1.4, table 59.1.2).
    The TSD provides additional information on our evaluation of the 
DAQM NSR submittal relative to Nonattainment NSR requirements.
PSD NSR Requirements
    Part C of title I of the Act contains the provisions, including 
preconstruction permit requirements for new major sources or major 
modifications, for the prevention of significant deterioration (PSD) of 
air quality in areas designated as ``attainment'' or ``unclassifiable'' 
for the NAAQS. EPA's regulations for PSD permit programs are found in 
40 CFR 51.166 and 40 CFR 52.21. Except for CO and PM-10 in Las Vegas 
Valley (hydrographic area 212), Clark County is designated as 
``attainment'' or ``unclassifiable'' for the NAAQS. See 40 CFR 81.329.
    EPA offers States (and local air districts) two mechanisms by which 
to

[[Page 31060]]

administer PSD permitting programs. First of all, EPA may delegate the 
PSD permitting authority of 40 CFR 52.21 to a State or air district. 
For instance, EPA has provided a partial delegation of authority to 
NDEP to administer the Federal PSD program (set forth in 40 CFR 52.21). 
See 68 FR 52837 (September 8, 2003). Thus, NDEP and EPA now share 
responsibility for administering the PSD program as it relates to major 
new, or major modifications at, plants which generate electricity by 
using steam produced by the burning of fossil fuel in Clark County 
(note that, in the nonattainment portion of Clark County (Las Vegas 
Valley), such new or modified plants are prohibited under NAC 
445B.22083).
    Alternatively, a State or air district may develop its own PSD 
program meeting the requirements of 40 CFR 51.166, and submit these 
rules for inclusion in the applicable SIP. The DAQM NSR submittal has 
been submitted for EPA approval under 40 CFR 51.166 as well as the 
nonattainment NSR provisions discussed in the previous subsection of 
this notice. With respect to the DAQM NSR submittal, we have concluded 
that it meets the applicable PSD NSR requirements on the basis of the 
following findings:
    1. The DAQM NSR submittal provides for implementation of best 
available control technology (BACT) for new major sources or major 
modifications as required in section 40 CFR 51.166(j) (see DAQM section 
12, subsections 12.2.3.2, 12.2.4.2, and 12.2.5.2 (PM-10); subsections 
12.2.8.2, 12.2.9.3, and 12.2.10.2 (CO); subsections 12.2.11.2, 
12.2.12.3, and 12.2.13.2 (volatile organic compounds (VOC)); 
subsections 12.2.14.4 and 12.2.15.2 (oxides of nitrogen 
(NOX)); and subsections 12.2.16.2 (sulfur dioxide 
(SO2)), 12.2.17.2 (lead (Pb)), and 12.2.19.7 (non-criteria 
pollutants subject to PSD)).
    2. The DAQM NSR submittal provides for an appropriate air quality 
analysis, including pre-application air monitoring and post-
construction monitoring, as required in 40 CFR 51.166(m) (see DAQM 
section 12, subsections 12.2.4.4, 12.2.4.5, 12.2.5.4, and 12.2.5.5 (PM-
10); subsections 12.2.9.2, 12.2.10.4, and 12.2.10.5 (CO); subsections 
12.2.12.2, 12.2.13.4, and 12.2.13.5 (VOC); subsections 12.2.14.3, 
12.2.15.4 and 12.2.15.5 (NOX); subsections 12.2.16.4 and 
12.2.16.5 (SO2); subsections 12.2.17.4 and 12.2.17.5 (Lead); 
subsections 12.2.19.1 and 12.1.19.2 (non-criteria PSD pollutants; 
subsections 12.5.5 (PSD monitoring significance levels), 12.6.1 (pre-
construction ambient air monitoring requirements), and 12.6.2 (post-
construction ambient air monitoring requirements)).
    3. The DAQM NSR submittal establishes the appropriate maximum 
allowable ambient air increments (see DAQM section 12, subsections 
12.2.3.5, 12.2.4.6, and 12.2.5.6 (PM-10); subsections 12.2.14.3 and 
12.2.15.6 (NOX); subsection 12.2.16.6 (SO2)) and 
ambient air ceilings (see DAQM section 12, subsections 12.2.3.5(b), 
12.2.4.6(c), and 12.2.5.6(c) (PM-10); subsections 12.2.9.2 and 
12.2.10.4(c) (CO); subsections 12.2.12.2 and 12.2.13.4(b) (VOC); 
subsections 12.2.14.3 and 12.2.15.6(c) (NOX); subsections 
12.2.16.6(c) (SO2) and 12.2.17.4 (Lead)) as required in 40 
CFR 51.166(c) and (d). DAQM implements the ambient air ceilings by 
reference to submitted DAQM section 11, which contains the current 
NAAQS.
    4. The DAQM NSR submittal provides for completion of appropriate 
additional impact analyses related to visibility, soils, and vegetation 
and appropriate additional air quality impact analysis related to 
general land use development as required in 40 CFR 51.166(o) (see DAQM 
section 12, subsections 12.2.4.7 and 12.2.5.7 (PM-10); subsections 
12.2.9.2 and 12.2.10.6 (CO); subsections 12.2.12.2 and 12.2.13.6 (VOC); 
subsections 12.2.14.3 and 12.2.15.7 (NOX); and subsections 
12.2.16.7 (SO2), 12.2.17.6 (Lead), and 12.2.19.3 (non-
criteria PSD pollutants)).
    5. The DAQM NSR submittal provides for the appropriate Class II PSD 
classification for all areas in Clark County based on their adopted 
maximum allowable ambient air increments discussed above.
    6. The DAQM NSR submittal provides for protection of air quality 
related values (including visibility) in Class I areas as required in 
40 CFR 51.166(p) (see DAQM section 12, subsections 12.2.4.6(b), 
12.2.4.8, 12.2.5.6(b), and 12.2.5.8 (PM-10); subsections 12.2.9.2 and 
12.2.10.7 (CO); subsections 12.2.12.2 and 12.2.13.7 (VOC); subsections 
12.2.14.3, 12.2.15.6(b), and 12.2.15.8 (NOX); subsections 
12.2.16.6(b) and 12.2.16.8 (SO2); subsection 12.2.17.7 
(Lead); subsection 12.3.1.2(b) (notification of the Federal Land 
Manager (FLM) or other appropriate Federal official); subsection 
12.3.4.4 (framework for coordination between DAQM and the FLM or other 
appropriate Federal official concerning potential impacts to Class I 
areas)).
    7. The DAQM NSR submittal provides for agency and public 
participation as required in 40 CFR 51.166(p)(1) and 51.166(q) (see 
DAQM section 12, subsections 12.3.1.2(b), 12.3.2, and 12.4.4)).
    The TSD provides additional information on our evaluation of the 
DAQM NSR submittal relative to PSD NSR requirements.
Section 110(l) of the Act
    Section 110(l) of the Act prohibits EPA from approving any revision 
of a SIP if the revision would interfere with any applicable 
requirement concerning attainment and reasonable further progress, or 
any other applicable requirement of the Act. For attainment pollutants 
in attainment areas, our evaluation considers first whether a submitted 
SIP revision would be as stringent as the provision in the existing 
applicable implementation plan that it would supercede. If so, then no 
further analysis is generally required. But, even if we cannot conclude 
that a SIP revision is as stringent as the corresponding provision in 
the applicable implementation plan, we may still approve the revision 
so long as it can be shown that the revision would not interfere with 
any applicable requirement concerning attainment and reasonable further 
progress, or any other applicable requirement of the Act.
    For nonattainment pollutants in nonattainment areas, one court has 
ruled that our evaluation must extend beyond the issue of whether the 
submitted SIP revision is as stringent as the existing SIP provision 
that it would supercede and consider the submitted SIP revision in 
light of current ambient air quality and nonattainment planning 
requirements within the applicable nonattainment area. See Hall v. EPA, 
273 F.3d 1146 (9th Cir. 2001). No other court has yet decided this 
issue. In nonattainment areas too, we may approve SIP relaxations under 
section 110(l) so long as they would not interfere with any applicable 
requirement concerning attainment and reasonable further progress, or 
any other applicable requirement of the Act (such as section 193 of the 
Act, discussed in the next section of this TSD).
    Based on the detailed pollutant-by-pollutant evaluation we provide 
in the TSD (and summarize herein), which includes an evaluation of the 
incremental SIP strengthenings and relaxations in the context of 
pollutant emission sources, trends, air quality conditions, and 
planning requirements, we conclude that approval of the DAQM NSR 
submittal (and thereby replacement or supercession of the existing SIP 
NSR rules) would not interfere with any applicable requirement 
concerning attainment and reasonable further

[[Page 31061]]

progress, or an other applicable requirement of the Act.
    Most of the significant differences between the two NSR programs 
(SIP-approved versus the DAQM NSR submittal) are pollutant-specific 
rather than of general applicability. There are, however, two 
differences of general applicability that warrant discussion here: the 
emissions test used to define a stationary source modification and the 
basis for the minor (referred to as ``non-major'' under the submitted 
DAQM NSR program) source baseline date.
    First, the DAQM NSR submittal would replace a ``potential-to-
potential'' test with an ``actual-to-potential'' test for evaluating 
proposed stationary source modifications (see existing SIP section 1, 
``modification'' (1.52)). As a result, the existing SIP rule fails to 
require NSR review for modifications at major sources, which involve a 
significant net emissions increase in actual emissions, but no increase 
in the potential to emit. In contrast, the DAQM NSR submittal provides 
for the more protective ``actual-to-potential'' test for evaluating 
proposed modifications at major sources. This would represent a general 
strengthening of the NSR program compared to the existing SIP NSR 
program. For additional Agency discussion on the relative stringency of 
these two different tests for determining applicability of requirements 
for modifications, see our final rule on recent NSR revisions at 67 FR 
80186 at 80204-80206 (December 31, 2002).
    Second, through the definition of ``baseline concentration'' in SIP 
section 1, the existing SIP established a uniform minor source baseline 
date of August 7, 1977 in the various PSD baseline areas (which derive 
from the areas designated as attainment or unclassifiable by EPA under 
section 107(d) of the Act) within Clark County. This definition is 
consistent with EPA's 1978 final PSD regulations. However, the court in 
the Alabama Power decision set aside EPA's definition (from the 1978 
PSD regulations) in favor of the statutory definition of the term (see 
section 169(4) of the Act), which links the baseline concentration to 
the ambient concentration that exists at the time of the first PSD 
application in a given area. See Alabama Power Co. v. Costle, 636 F.2d 
323, at 375-376 (D.C. Cir. 1979). EPA's PSD regulations have long since 
been revised to reflect the court's holding (see 40 CFR 51.166(b)(13)).
    While the definition of ``baseline concentration'' in DAQM section 
0 is consistent with the current EPA definition, EPA approval of this 
definition to supercede the SIP definition would have the effect of 
untriggering (completely) the minor source baseline dates for PM and 
SO2 in those section 107(d) attainment or unclassifiable 
areas in which no source or modification has submitted a complete PSD 
application or would have a significant impact. Examples of such areas 
include Frenchman Flat (hydrographic area (HA) 160), Indian Springs 
Valley (HA 161), and Pahrump Valley (HA 162).
    For those areas in which a source or modification has submitted a 
complete PSD application or would have a significant impact, EPA 
approval would have the effect of establishing a new minor source 
baseline date for PM or SO2 or both, i.e., from August 7, 
1977 to various different (more recent) dates in the applicable areas. 
Examples include Las Vegas Valley (HA 212), which would have a new 
minor source baseline date for SO2 of April 25, 1996 
(triggered by a complete PSD application submitted by TIMET) and Black 
Mountains (HA 215), which would have a new minor source baseline date 
for PM of December 14, 1990 (triggered by a complete PSD application 
submitted by NCA 2).
    Arguably, untriggering (or re-establishing new, more recent) minor 
source baseline dates represents a relaxation because a greater level 
of air quality degradation would be allowed compared to a regulatory 
scheme in which the baseline date and concentration is set uniformily 
for all areas at August 7, 1977. However, this particular type of 
change aligns the Clark County NSR program with the statute (see 
section 169(4) of the Act) and thus, can also be viewed as a correction 
rather than as a relaxation. We conclude, therefore, that approval of 
the DAQM NSR submittal would serve the Congressional purposes described 
in the Alabama Power decision, and that the untriggering (or re-
setting) of PSD minor source baseline dates in Clark County under these 
circumstances would be consistent with section 110(l) of the Act. 
Section 110(l) prohibits interference with any applicable requirement 
of the Act, and in this case the SIP revision will bring the Clark 
County program in line with the requirements of the Act as interpreted 
by the court. Thus, EPA concludes that approval is consistent with 
section 110(l). We also note that our approval of the DAQM NSR 
submittal would have little practical effect on the PSD program as it 
is being administered currently by DAQM since DAQM has not been 
administering the program under the assumption that there is a uniform 
county-wide minor source baseline date (i.e., as provided for in the 
existing SIP NSR program) but rather under the assumption that the 
minor source baseline date is triggered on an area-by-area basis by the 
submittal of the first complete PSD application in a given area.
    Carbon Monoxide (CO). As noted previously, a sub-region within 
Clark County, the Las Vegas Valley (hydrographic area 212), is 
designated as a ``serious'' nonattainment area for the CO NAAQS. Clark 
County has developed and adopted a ``serious area'' attainment plan 
which relies primarily on the Federal motor vehicle control program, 
and State and local wintertime gasoline specifications (such as DAQM 
sections 53 (Oxygenated Gasoline Program) and 54 (Cleaner Burning 
Gasoline), and an ``enhanced'' motor vehicle inspection and maintenance 
program to demonstrate attainment of the CO NAAQS by the applicable 
attainment date (year 2000). We have proposed approval of this plan. 
See 68 FR 4141 (January 28, 2003) for our proposed approval of the Las 
Vegas Valley ``serious area'' CO attainment plan. The rest of the 
county is designated unclassifiable/attainment for the CO NAAQS. See 40 
CFR 81.329.
    Approval of the DAQM NSR submittal (and thereby replacement or 
supercession of the existing SIP NSR rules) would represent an 
incremental relaxation in the control technology requirement for new or 
modified non-major CO sources within Las Vegas Valley (i.e., from LAER 
to BACT), but would also represent an incremental strengthening by 
imposing more stringent offset requirements. The offset requirements 
would be strengthened in two respects: the threshold for the offset 
requirement would be lowered to 70 tons per year (tpy) from 100 tpy and 
the offset ratio would be increased to 2:1 from 1:1. Given (1) that the 
more inclusive ``actual-to-potential test'' would replace the 
``potential-to-potential'' test for evaluating source modifications; 
(2) that the incremental relaxation in the control technology 
requirement would replace the highest level of control (LAER) with the 
next highest (BACT) level of control and this incremental difference is 
offset by an incremental strengthening in the offset requirement; (3) 
that DAQM section 12 prohibits new or modified CO stationary sources 
with potentials to emit (PTEs) greater than 50 tpy in the downtown CO 
``hot spot'' area; (4) that the Las Vegas Valley ``serious area'' CO 
attainment plan assumes growth in non-major stationary CO sources 
(i.e., does not assume that the CO emissions from non-major sources 
would be offset), concludes that stationary sources are

[[Page 31062]]

not a significant contributor to CO levels in the valley, and does not 
rely on stationary source controls to demonstrate attainment; and (5) 
that EPA has proposed approval of the CO attainment demonstration based 
on on-road motor vehicle controls, we have concluded that the 
supercession of the existing SIP NSR program by the submitted NSR 
program would not interfere with the CO attainment strategy or any 
other applicable requirement of the Act.
    Particulate Matter (PM-10). As noted previously, Las Vegas Valley 
(hydrographic area 212), is designated as a ``serious'' 
nonattainment area for the PM-10 NAAQS. Clark County has developed and 
adopted a ``serious area'' attainment plan which relies primarily on 
prohibitory rules regulating fugitive dust sources, including vehicle 
travel over paved and unpaved roads and construction activity, to 
demonstrate attainment of the PM-10 NAAQS by year 2006. We have 
proposed approval of this plan. See 68 FR 2954 (January 22, 2003) for 
our proposed approval of the Las Vegas Valley ``serious area'' PM-10 
attainment plan. The rest of the county is designated on a hydrographic 
area basis as ``unclassifiable'' for the PM-10 NAAQS, see 40 CFR 
81.329, but PM-10 NAAQS violations have been recorded in Apex Valley, 
which borders Las Vegas Valley to the north.
    In general, approval of the DAQM NSR submittal would strengthen the 
SIP by updating the PM increments in terms of PM-10 (rather than total 
suspended particulate (TSP)). EPA replaced the PM NAAQS, measured as 
TSP, with new PM NAAQS, measured as PM-10, in 1987. See 52 FR 24634 
(July 1, 1987). With respect to Las Vegas Valley, approval of the DAQM 
NSR submittal (and thereby replacement or supercession of the existing 
SIP NSR rules) would represent an incremental relaxation in the control 
technology requirement for new or modified non-major PM-10 sources 
(i.e., from the most stringent level of control, LAER to the next 
highest level of control, BACT), and in the offset requirement (from 
``federal'' to ``local'' offsets) for new or modified sources with PTEs 
from 15 tpy (as adjusted from 25 tons TSP) to 70 tpy, but it would also 
represent an incremental strengthening by establishing a more stringent 
offset ratio (2:1) to replace the current ratio (1:1). Given (1) that 
the more inclusive ``actual-to-potential test'' would replace the 
``potential-to-potential test'' for evaluating source modifications; 
(2) that the offsetting effects of these changes to the NSR program 
would ensure a negligible effect on PM-10 emissions; (3) that the 
submitted NSR program conforms to that PM-10 attainment plan in that 
the plan assumes BACT- rather than LAER-level of control for new or 
modified non-major sources in Las Vegas; (4) that the Las Vegas Valley 
``serious area'' PM-10 attainment plan concludes that stationary 
sources are not a significant contributor to PM-10 NAAQS violations in 
the valley, and does not rely on stationary source controls to 
demonstrate attainment; and (5) that EPA has proposed approval of the 
demonstration based on fugitive dust controls, we have concluded that 
the supercession of the existing SIP NSR program by the submitted NSR 
program would not interfere with the PM-10 attainment strategy or any 
other applicable requirement of the Act.
    With respect to Apex Valley, the incremental relaxation in the 
control technology requirement (from LAER to BACT) and the elimination 
of any offset requirement, when viewed in isolation, could appear to 
potentially interfere with attainment of the PM-10 NAAQS in that area 
given the monitored incidence of PM-10 NAAQS violations in the area. 
However, EPA recognizes that Clark County is in the process of 
extending additional regulatory controls to existing PM-10 sources in 
the Apex Valley and to developing a Natural Events Action plan to 
address those PM-10 NAAQS violations that result from high wind events 
that occur there, and in that context, EPA believes that the 
incremental relaxation in requirements for new or modified stationary 
sources would not interfere with attainment of the PM-10 NAAQS in Apex 
Valley since the attainment strategy, by necessity, will focus on 
existing sources and high-wind-driven fugitive dust.
    Ozone. Las Vegas Valley (hydrographic area 212) was 
designated as a nonattainment area for the ozone NAAQS in 1978. 
Pursuant to the Clean Air Act Amendments of 1977, Clark County 
developed and adopted the Las Vegas Valley Air Quality Implementation 
Plan in 1978 as an attainment plan for the ozone NAAQS. This plan was 
revised in 1980 and then again in 1984. The attainment strategy relied 
primarily on the Federal motor vehicle emission control program, the 
NSR program (i.e., existing SIP sections 1, 11, and 15), and various 
stationary source prohibitory rules (including SIP sections 33, 50, 51, 
52, and 60), which relate to sources of chlorine (found to be a 
significant ozone precursor in Las Vegas Valley) and VOC sources, such 
as petroleum product storage and handling. We approved these plan 
submittals at various times (see, e.g., 51 FR 29923, August 21, 1986). 
Based on monitoring data documenting the necessary decrease in peak 
ozone concentrations, we redesignated Las Vegas Valley as 
``attainment'' for the (one-hour) ozone NAAQS in 1986. See 51 FR 41788 
(November 19, 1986). Since then, peak ozone levels have remained 
relatively constant at 0.09 parts per million (ppm) to 0.10 ppm, but 
peak levels in recent years have approached the one-hour standard of 
0.12 ppm. The current (one-hour) ozone NAAQS designation for Clark 
County is unclassifiable/attainment. See 40 CFR 81.329.
    Approval of the DAQM NSR submittal (and thereby replacement or 
supercession of the existing SIP NSR rules) would represent an 
incremental relaxation in the control technology requirement for new or 
modified non-major VOC sources within Las Vegas Valley (i.e., from LAER 
to BACT), however, the DAQM NSR submittal extends LAER level of control 
to new or modified major VOC sources proposed for certain locations 
adjacent to, and generally upwind of Las Vegas Valley (i.e., Eldorado 
Valley and Ivanpah Valley. In these adjacent areas, the applicable 
control technology requirement under the existing SIP NSR rules is 
BACT. Given that the 1980's-era ozone attainment strategy relies on 
several important VOC regulatory elements that would not be affected by 
our action on the NSR program, e.g., stationary source prohibitory SIP 
rules (i.e., SIP sections 33, 50, 51, 52, and 60) and motor vehicle 
tailpipe and fuel regulations promulgated by EPA under title II of the 
Act, and that the incremental relaxation in the control technology 
requirement for new or modified sources of VOC in Las Vegas Valley 
would replace the highest level of control (LAER) with the next highest 
level of control (BACT) and would be partially offset by an incremental 
strengthening in that requirement in upwind areas, we have concluded 
that the approval of the DAQM NSR submittal (and thereby replacement or 
supercession of the existing SIP NSR rules) would not interfere with 
continued attainment of the one-hour ozone NAAQS or any other 
applicable requirement of the Act. We note that Clark County has been 
designated as nonattainment for the eight-hour ozone NAAQS, which EPA 
established in 1997 (62 FR 38856, July 19, 1997) and which will in time 
replace the existing (one-hour) ozone NAAQS. 69 FR 23858, 23919-23920 
(April 30, 2004). Additional changes to the DAQM NSR program will be 
required on a schedule

[[Page 31063]]

to be established by EPA in a final rule implementing the eight-hour 
ozone NAAQS. See 69 FR 23951, 23985-23986 (April 30, 2004).
    Nitrogen Dioxide (NO2). Clark County is designated on a 
hydrographic area basis as unclassifiable/attainment for the 
NO2 NAAQS. See 40 CFR 81.329. Ambient NO2 
concentrations are well below (approximately 50%) the applicable NAAQS.
    As a general matter, approval of the DAQM NSR submittal would 
strengthen the SIP by establishing NO2 PSD increments and 
requiring the related NO2 PSD increment consumption analysis 
for new major sources or major modifications in Clark County. Within 
Las Vegas Valley, approval of the DAQM NSR submittal (and thereby 
replacement or supercession of the existing SIP NSR rules) would relax 
the control technology requirement for new or modified sources of 
NOX (from LAER to BACT), but this relaxation would be offset 
by the special restrictions established in DAQM section 12 for new or 
modified NOX sources in the urbanized core of Las Vegas. 
From the standpoint of continued attainment of the NO2 
NAAQS, while the net effect (negative or positive) of these offsetting 
regulatory changes is difficult to predict, it would not be expected to 
be significant given that the relaxed control technology requirement is 
from the highest level of control (LAER) to the next highest level of 
control (BACT) rather than an elimination of the control technology 
requirement completely and given that, as noted above, ambient 
NO2 concentrations are well below the applicable NAAQS. 
Thus, we have concluded that the supercession of the existing SIP NSR 
program by the submitted NSR program would not interfere with continued 
attainment of the NO2 NAAQS or any other applicable 
requirement of the Act.
    Sulfur Dioxide (SO2). Clark County is designated on a 
hydrographic area basis as unclassifiable/attainment for the 
SO2 NAAQS. See 40 CFR 81.329. SO2 monitoring data 
collected in Las Vegas Valley in the early 1980's indicate that the 
highest ambient concentrations were between 5% and 22% of the 
respective NAAQS depending upon the averaging period. Monitoring data 
from year 2002 show little change in ambient SO2 
concentrations relative to conditions in the early 1980's.
    Approval of the DAQM NSR submittal (and thereby replacement or 
supercession of the existing SIP NSR rules) would represent an 
incremental relaxation in the control technology requirement for new or 
modified SO2 sources within Las Vegas Valley (i.e., from 
LAER to BACT) and an incremental relaxation in the ambient 
SO2 standards used in the impact analyses conducted as part 
of the permit application process for new or modified sources 
(comparing the SO2 ambient standards in existing SIP section 
11 with submitted DAQM section 11). From the standpoint of continued 
attainment of the SO2 NAAQS, EPA concludes that the 
incremental relaxation of the control technology requirement in Las 
Vegas Valley for new or modified sources of SO2 is not 
significant given that the relaxed requirement is from the highest 
level of control (LAER) to the next highest level of control (BACT) 
rather than an elimination of the control technology requirement 
completely and given that ambient SO2 concentrations 
continue to be well below the applicable NAAQS. Also, NDEP has 
jurisdiction over one of the principal sources of SO2 (coal-
burning power plants) in Clark County, and the control technology 
requirements for SO2 emissions from those sources are 
unaffected by this action. Finally, the incremental relaxation in 
SO2 ambient air quality standards used in the permit 
application evaluation process is consistent with continued attainment 
of the NAAQS since the revised ambient standards in submitted DAQM 
section 11 accurately reflect the current NAAQS for SO2. 
Thus, we have concluded that supercession of the existing SIP NSR 
program by the submitted NSR program would not interfere with continued 
attainment of the SO2 NAAQS or any other applicable 
requirement of the Act.
    Lead. EPA promulgated the NAAQS for lead (Pb) in 1978. See 43 FR 
46246 (October 5, 1978). Ambient lead levels collected in Las Vegas 
Valley during the late 1970's were found to violate the NAAQS. To 
provide for the attainment and maintenance of the lead NAAQS in the 
valley, Clark County adopted the State Implementation Plan Revision for 
Ambient Lead in Las Vegas Valley, Clark County, Nevada (dated February 
11, 1980). EPA approved this plan as a SIP revision in 1982. See 47 FR 
28374 (June 30, 1982). This lead (Pb) attainment plan predicted 
attainment of the lead NAAQS prior to 1982 primarily based on the 
declining lead content of motor vehicle gasoline, and indeed, maximum 
quarterly concentrations were much less than the NAAQS by the mid-
1980's.
    In general, the DAQM NSR submittal represents a strengthening of 
the SIP with respect to lead in those portions of Clark County that lie 
outside of Las Vegas Valley but an incremental relaxation of the SIP 
within Las Vegas Valley. However, from the standpoint of continued 
attainment of the lead NAAQS in Las Vegas Valley, the relaxation of 
certain NSR requirements for new or modified stationary sources of lead 
(de minimis exemptions, a BACT control technology requirement rather 
than LAER, elimination of offsets) would not interfere with continued 
attainment of the lead NAAQS nor any other requirement of the Act 
because the incremental relaxation of the control technology 
requirement is from the highest level of control (LAER) to the next 
highest level of control (BACT) rather than an elimination of the 
control technology requirement completely and because the DAQM NSR 
submittal continues to ensure that permits are not issued to new or 
modified sources that would cause a violation of the lead NAAQS (see 
DAQM section 12, subsection 12.2.17.4(c)). Moreover, the overwhelming 
influence of mobile sources to the historical lead NAAQS violations, 
which would be unaffected by approval of the DAQM NSR submittal, and 
the low background lead concentrations further ensure that supercession 
of the existing NSR SIP program with the submitted NSR SIP program 
would not interfere with continued attainment of the lead NAAQS or any 
other requirement of the Act.
Section 193 of the Act
    Section 193 of the Act, which was added by Congress in the Clean 
Air Act Amendments of 1990, includes a savings clause which provides, 
in pertinent part: ``No control requirement in effect, or required to 
be adopted by an order, settlement agreement, or plan in effect before 
November 15, 1990, in any area which is a nonattainment area for any 
air pollutant may be modified after November 15, 1990, in any manner 
unless the modification insures equivalent or greater emission 
reductions of such air pollutant.'' This section of the Act does not 
clearly apply to revisions in NSR programs, but we have evaluated the 
DAQM NSR submittal on the assumption that section 193 does apply. NSR 
program revisions are inherently difficult to evaluate with respect to 
changes in emissions reductions because NSR covers all types of 
stationary sources and provides for case-by-case evaluations of control 
technology requirements whether the applicable requirement is BACT or 
LAER (see 40 CFR 51.166(b)(12) and 40 CFR 51.165(a)(1)(xiii)). In the 
context of the DAQM NSR submittal, a determination of whether the 
submitted NSR program would provide for equivalent or greater

[[Page 31064]]

emission reductions relative to the existing SIP NSR program is further 
complicated by the comprehensive nature of the changes. The DAQM NSR 
submittal represents a wholesale revision affecting the substance, 
procedure, and format of the Clark County NSR program. Nevertheless, we 
can identify three parameters that most closely link to relative 
changes in emissions reductions from new or modified stationary 
sources: the test for evaluating source modifications, the control 
technology review, and the requirements for offsets, including offset 
thresholds, offset ratios, and the other specifications for creation 
and use of offsets. As explained below, relaxation in some of these 
parameters is offset by countervailing strengthenings in other 
parameters with the net result that we can conclude that the submitted 
NSR program will provide for equivalent or greater emissions reductions 
as the existing SIP NSR program (which pre-dates the 1990 Clean Air Act 
Amendments) for the two applicable nonattainment pollutants, CO and PM-
10.
    Test for Source Modifications. As noted previously, the submitted 
DAQM NSR program would establish the more inclusive test (``actual to 
potential'') for evaluating source modifications and thereby replace 
the existing SIP NSR program's ``potential-to-potential'' test, with 
the result that a greater number of source modifications would be 
subject to new source review and the related requirements of BACT or 
LAER.
    Control Technology Requirements. Under the existing SIP NSR 
program, the highest level of control (LAER) applies to all new or 
modified sources of CO or PM in the nonattainment area. In contrast, 
under the submitted DAQM NSR program, the next highest level of 
control, BACT, applies to new or modified sources of CO and PM with 
PTEs less than 70 tpy. Under the submitted NSR program, LAER applies at 
70 tpy or greater for CO and PM-10.
    Offsets Requirements. Offsets requirements refer to applicable 
thresholds, ratios, and specifications such as whether offsets are 
surplus, permanent, quantifiable and federally enforceable. With 
respect to offset thresholds, for CO, offsets under the existing SIP 
NSR program apply to sources or modifications with PTEs greater than 
100 tpy, whereas, under the submitted NSR program, offsets apply at 70 
tpy. For PM, offsets under the existing SIP NSR program apply to 
sources or modifications with PTEs greater than 25 tpy (based on TSP, 
which is roughly equivalent to 15 tpy PM-10). The corresponding 
threshold under the submitted NSR program is 70 tpy of PM-10. With 
respect to offset ratios, for both CO and PM, the existing SIP NSR 
program establishes a 1:1 ratio whereas the submitted NSR program 
establishes a more stringent a 2:1 ratio. With respect to specific 
characteristics of offsets, DAQM section 59 requires that offsets be 
surplus, permanent, quantifiable and federally enforceable as defined 
in DAQM section 0. See DAQM section 59, subsection 59.4.2.1, and the 
related definitions in DAQM section 0. Section 15 does not have any 
similar requirements for offsets.
    Evaluation for Carbon Monoxide. First, as noted above, the 
submitted program would establish the more inclusive ``actual-to-
potential'' test for evaluating source modifications. Second, the 
submitted program would establish a lower threshold for triggering 
offset requirements (70 tpy under the submitted NSR program versus 100 
tpy under the existing SIP NSR program), would establish a higher 
offset ratio (2:1 versus 1:1), and would establish the requirements for 
creation and use of offsets (surplus, permanent, quantifiable and 
federally enforceable) that ensure that emissions increases are truly 
offset. Thus, two of the three parameters strongly support a conclusion 
that the submitted program would provide equivalent or greater CO 
emissions reductions relative to the existing SIP NSR program.
    One of the three parameters, the control technology requirement, is 
more stringent for non-major sources under the existing SIP NSR program 
than under the submitted program. The existing SIP NSR program requires 
LAER-level of control for non-major CO sources whereas the submitted 
DAQM NSR program requires BACT-level of control for such sources. The 
emissions reductions associated with application of LAER-level of 
control relative to those associated with application of BACT-level of 
control depend upon the type and size of proposed sources or 
modifications. In some instances, due to the ``top-down'' approach used 
in BACT analyses, which requires justification for not selecting LAER-
level of control before evaluating less stringent levels of control, 
BACT is equivalent to LAER. This ``top-down'' approach for determining 
BACT is described in detail in Chapter B of EPA's Draft New Source 
Review Workshop Manual (October 1990). In most other instances, the 
differences in emissions limitations between the two levels of control 
are relatively small, particularly in relation to emissions that would 
otherwise result from an uncontrolled source.
    Thus, we have concluded that the CO emissions increase associated 
with the incremental relaxation associated with the control technology 
requirement for non-major sources, which should be relatively minor 
given the small difference between emissions limitations under BACT 
versus LAER in most circumstances, would be more than compensated for 
by the more inclusive test for source modifications, the lower CO 
offset threshold, the higher CO offset ratio, and the establishment of 
other requirements for offsets that ensure that they truly offset 
emissions from applicable new sources or modifications.
    Evaluation for Particulate Matter. As noted above, the submitted 
DAQM NSR program would establish the more inclusive ``actual-to-
potential'' test for evaluating source modifications.
    The second parameter, the control technology requirement (LAER), is 
more stringent for non-major sources under the existing SIP NSR program 
than under the submitted program (BACT). As described above for CO, 
however, the difference between the emissions reductions associated 
with application of LAER-level of control relative to those associated 
with application of BACT-level of control typically ranges from minor 
to none at all.
    With respect to requirements for PM offsets, the differences 
between the existing SIP and submitted NSR programs are particularly 
difficult to evaluate. On one hand, the existing SIP NSR program has 
established a lower offset threshold at 25 tpy of TSP (which is roughly 
equivalent to 15 tpy of PM-10), compared to 70 tpy of PM-10 under the 
submitted program. On the other hand, the existing program has 
established a lower offset ratio (1:1 versus 2:1).
    Moreover, the ``quality'' of the offsets under the existing program 
is lower than that required under the submitted program in two 
respects. First, unlike the submitted program, the existing SIP NSR 
program does not require that offsets be surplus, permanent, 
quantifiable and federally enforceable and thus does not ensure that 
increases in emissions are truly offset. Second, the existing SIP NSR 
program allows TSP offsets to be used to offset increases in PM 
emissions. Depending upon the particle size distribution of those TSP 
offsets, it is possible that increases in PM-10 emissions under the 
existing SIP NSR program would not be offset by PM-10 offsets at all. 
In other words, a new source that generates particulate matter that is 
largely or entirely of the particle size constituting PM-10 could be 
``offset'' under the existing program

[[Page 31065]]

by another source whose PM emissions are largely or entirely of a 
particle size not constituting PM-10 but still constituting TSP (TSP 
includes particles roughly 30 microns in diameter or less). In such 
circumstances, the PM-10 emissions increase at the new source would be 
at most only partially offset since the ``offsets'' do not, or only 
partially, constitute PM-10. In contrast, the submitted program, while 
it does not require offsets for as many new sources as the existing 
program (due to the higher offset threshold), does require that PM-10 
emissions increases be offset by PM-10 offsets, i.e., where offsets are 
required.
    In conclusion, while we recognize the significant trade-offs in 
emission reduction potential between the two NSR programs with respect 
to PM-10, we have concluded that the PM-10 emissions increase 
associated with the incremental relaxation associated with the control 
technology requirement for non-major sources and the higher offset 
threshold would be more than compensated for by the more inclusive test 
for source modifications, the higher PM-10 offset ratio, the 
establishment of other requirements for offsets that ensure that they 
truly offset emissions from applicable new sources or modifications, 
and the requirement to use PM-10 offsets rather than TSP offsets, only 
some fraction of which constitutes PM-10.
    Conclusion. For the reasons set forth above, we propose to find 
that the submitted DAQM NSR program insures equivalent or greater 
emissions reductions of CO and PM-10 as compared to the existing SIP 
NSR program in compliance with section 193 of the Act.
Proposed Partial Approval
    Pursuant to section 110(k)(3) of the Act, we propose a partial 
approval of the submitted NSR rules. With the exceptions listed in the 
following subsection of this notice, we propose approval of the 
submitted NSR rules, including DAQM sections 0, 11, 12, 58, and 59 and 
NAC 445B.22083, based on our determination that the rules comply with 
applicable statutory and regulatory provisions requiring regulation of 
stationary sources in general and requiring permit programs for major 
stationary sources in particular, including section 110(a)(2)(C) and 
parts C and D of title I of the Act. In support of this recommendation, 
we have concluded that our approval of the submitted NSR rules (and 
thereby replacement or supercession of the existing SIP NSR rules), 
i.e., with the partial exception for certain definitions in existing 
SIP section 1, complies with section 110(l) of the Act because the 
untriggering (or re-setting) of the minor source baseline dates for PM 
and SO2 would be consistent with the statutory purpose of 
linking such dates with collection of actual air quality data and 
because the relaxation of certain control technology and offset 
requirements would not interfere with the strategy for attainment of 
the CO and PM-10 NAAQS in Las Vegas Valley or the continued attainment 
of the other NAAQS in Clark County.
Proposed Partial Disapproval
    We are also proposing a partial disapproval of the DAQM NSR 
submittal. A discussion of the individual subsections of the submittal 
that we are proposing to disapprove is provided in the following 
paragraphs.
    1. We propose to disapprove submitted DAQM section 12, subsections 
12.2.18 (HAP sources in Clark County) and 12.2.20 (Additional 
Requirements for Stationary Sources with Beryllium, Mercury, Vinyl 
Chloride, or Asbestos Emissions in Clark County) to avoid potential 
confusion or conflict with the Federal NESHAPS/MACT regulatory program. 
Regulations governing hazardous air pollutant (HAP) emissions are 
generally not appropriate for incorporation into SIPs, which are 
intended under the Act to assure attainment and maintenance of the 
criteria air pollutants.
    2. We propose to disapprove DAQM section 52, subsection 52.8 
(Section 52 Offset Program), because it cannot be evaluated properly in 
the absence of a SIP submittal of the entire rule (section 52). DAQM 
revised subsection 52.8 to clarify the date when the emission reduction 
credit program will expire, but the emission reduction credit program 
is not a part of existing SIP section 52, different portions of which 
were approved by EPA in 1981 (see 46 FR 21758, April 14, 1981) and in 
1982 (see 47 FR 26386, June 18, 1982). Thus, consideration of this 
latest revision should be conducted only as part of an evaluation of 
the entire rule (i.e., DAQM section 52).
    A partial disapproval is appropriate in this instance given the 
explanation provided above and given that these three subsections 
(i.e., DAQM section 12, subsections 12.2.18 and 12.2.20, and DAQM 
section 52, subsection 52.8) are easily severable from the overall NSR 
submittal.
Recommendations for Improvements to DAQM NSR Rules
    The TSD describes rule deficiencies that do not preclude full 
approval of the DAQM NSR submittal but are recommended for the next 
time DAQM modifies the rules. These recommendations relate to such 
topics as use of consistent terms, greater coordination with NDEP 
concerning increment consumption, and consideration of any analysis of 
the impact of a major source or major modification on air quality 
related values in Class I areas provided by a Federal Land Manager or 
other Federal official during the permit application review period and 
provision of an explanation in the public notice in those instances 
which DAQM disagrees with a finding of such Federal official.

II. Corrections to, or Clarification of, the Clark County Portion of 
Nevada State Implementation Plan

    In pertinent part, section 110(k)(6) of the Act provides that 
whenever EPA determines that the EPA action approving, disapproving, or 
promulgating any plan or plan revision (or part thereof) was in error, 
EPA may in the same manner as the approval, disapproval, or 
promulgation revise such action as appropriate without requiring any 
further submission from the State. Such determination and the basis 
thereof shall be provided to the State and public. The EPA interprets 
this provision to authorize the Agency to make corrections to an 
approval, disapproval, or promulgation of a SIP revision when it is 
shown to EPA's satisfaction that an error occurred in failing to 
consider or inappropriately considering information available to EPA at 
the time of the approval, disapproval, or promulgation, or the 
information made available at the time of approval, disapproval, or 
promulgation is subsequently demonstrated to have been clearly 
inadequate.
    Over the years, EPA has taken numerous actions on revisions to the 
Clark County portion of the Nevada SIP. In the process, EPA has made 
certain errors, or took certain actions that warrant clarification, 
which are the subject of this proposed action. Each proposed correction 
or clarification is summarized below. The TSD for this proposed action 
provides additional discussion of these rules.
    SIP section 1, subsections 1.79, Significant Source of Total 
Chlorides, and 1.94, Total Chlorides. In the preamble to our final rule 
approving these defined terms into the SIP (46 FR 43141; August 27, 
1981), we said that we were taking no action on these two subsections, 
but then we proceeded to codify them in the ``Identification of plan'' 
section of 40 CFR part 52, subpart

[[Page 31066]]

DD (Nevada). As a result, we inadvertently approved these two 
subsections of local rule, SIP section 1 (Definitions), into the Clark 
County portion of the Nevada SIP. We are proposing now to delete these 
terms from the SIP and to codify this deletion by revising the 
appropriate paragraph under 40 CFR part 52, subpart DD (Nevada), 
section 1470 (Identification of plan).
    Former SIP section 12, Upset, Breakdown, or Scheduled Maintenance. 
EPA originally approved this rule into the SIP in 1973. See 38 FR 12702 
(May 14, 1973). In 1981, we reversed course and disapproved it and 
codified this disapproval by amending 40 CFR part 52, section 1478 
(then entitled ``Rules and Regulations''). See 46 FR 43141 (August 27, 
1981). Subsequently, Clark County renumbered its air pollution 
regulations and submitted a local rule (section) 25 also entitled 
``Upset, Breakdown, or Scheduled Maintenance,'' which we disapproved in 
1984. See 49 FR 10259 (March 20, 1984). In that 1984 final rule, we 
codified our disapproval of submitted section 25 by amending 40 CFR 
52.1483, but we also removed and reserved 40 CFR 52.1478 which had 
included the 1981 disapproval language related to section 12 (Upset, 
Breakdown, or Scheduled Maintenance). (Note that 40 CFR 52.1478 has 
subsequently been renamed ``Extensions.'') The end result of this 
sequence of rulemaking is that, while section 12 (Upset, Breakdown, or 
Scheduled Maintenance), originally approved by EPA in 1973, is no 
longer approved into the Nevada SIP (ever since disapproval action in 
1981), the current codification of the Nevada SIP in subpart DD 
(Nevada) of 40 CFR part 52 is not clear on this point. Therefore, we 
are proposing to clarify the status of former SIP (now disapproved) 
section 12 (Upset, Breakdown, or Scheduled Maintenance), as submitted 
on January 19, 1973, by revising the appropriate paragraph under 40 CFR 
part 52, subpart DD (Nevada), section 1470 (Identification of plan).
    SIP Section 15, Prohibition of Nuisance Conditions. EPA approved 
this rule into the Nevada SIP in 1973. See 38 FR 12702 (May 14, 1973). 
Clark County later renumbered its air quality regulations, and we 
subsequently approved a new local rule (section) 15 (Source 
Registration) into the SIP. That new SIP section 15 (Source 
Registration) had nothing to do with general nuisance conditions and 
thus did not supercede the old SIP rule 15 (Prohibition of Nuisance 
Conditions) in the Nevada SIP. However, general nuisance rules, such as 
SIP section 15 (Prohibition of Nuisance Conditions) are not appropriate 
for inclusion in SIPs, because they are not specifically directed at 
the attainment and maintenance of the NAAQS, and therefore, we are 
proposing to delete section 15 (Prohibition of Nuisance Conditions) 
from the SIP and to codify this deletion by revising the appropriate 
paragraph under 40 CFR part 52, subpart DD (Nevada), section 1470 
(Identification of plan).
    Disapproved section 25, subsection 25.1, untitled, but related to 
upset, breakdown or scheduled maintenance. In 1981, we disapproved this 
rule, which had been submitted to us on July 24, 1979. See 46 FR 43141 
(August 27, 1981). Through that 1981 action, we listed this rule in the 
``Identification of plan'' section of 40 CFR part 52, subpart DD 
(Nevada) but canceled out the apparent approval by codifying the 
corresponding disapproval in 40 CFR 52.1478. In 1984, we disapproved an 
amended version of local Clark County rule, section 25 (Upset, 
Breakdown, or Scheduled Maintenance), which had been submitted to us on 
November 17, 1981. See 49 FR 10259 (March 20, 1984). In the 1984 
action, we codified our disapproval of section 25 (Upset, Breakdown, or 
Scheduled Maintenance), submitted on November 17, 1981, by amending 40 
CFR 52.1483, but we also removed and reserved 40 CFR 52.1478 (then 
entitled ``Rules and Regulations''), which had included the 1981 
disapproval language related to section 25, subsection 25.2, as 
submitted on July 24, 1979. By removing the disapproval language but 
retaining the listing of section 25, subsection 25.1, in the 
``Identification of plan'' section of 40 CFR part 52, subpart DD 
(Nevada), we have inadvertently caused potential confusion as to the 
status of this particular rule with respect to the Nevada SIP. To 
eliminate this confusion, we are proposing to delete the listing of 
section 25, subsection 25.1 (untitled, but related to upset, breakdown 
or scheduled maintenance), by revising the appropriate paragraph under 
40 CFR part 52, subpart DD (Nevada), section 1470 (Identification of 
plan).
    SIP section 29 (Odors in the Ambient Air). EPA originally approved 
this rule into the SIP in 1973. See 38 FR 12702 (May 14, 1973). Clark 
County later renumbered its air pollution regulations, and we 
subsequently approved a new local rule (section) 29 (Sulfur Content in 
Fuel Oil) into the SIP. See 46 FR 43141 (August 27, 1981). The new SIP 
section 29 (Sulfur Content in Fuel Oil) was completely different than 
the old SIP section 29 (Odors in the Ambient Air) and thus did not 
supercede it, nor have we taken specific action to delete the old SIP 
section 29 (Odors in the Ambient Air) from the Nevada SIP. Thus, 
section 29 (Odors in the Ambient Air), submitted on January 19, 1973, 
remains in the Nevada SIP. Odor nuisance rules are generally not 
appropriate for inclusion in the SIP, because they are not specifically 
directed at the attainment and maintenance of the NAAQS. Therefore, we 
are proposing to delete section 29 (Odors in the Ambient Air), 
submitted on January 19, 1973, from the Nevada SIP and to codify the 
deletion by revising the appropriate paragraph under 40 CFR part 52, 
subpart DD (Nevada), section 1470 (Identification of plan).
    SIP section 33, Chlorine in Chemical Processes. This local rule was 
adopted on May 18, 1984, and was included in the Las Vegas Valley Air 
Quality Implementation Plan, Post 1982 Update for Ozone, which was 
adopted by Clark County on October 16, 1984, submitted by NDEP on 
January 11, 1985, and approved by EPA as a SIP revision on August 21, 
1986 (51 FR 29923). The codification of our approval of the post-1982 
ozone plan, however, does not provide a separate listing of section 33, 
which could result in confusion as to the status of that rule with 
respect to the SIP. See 40 CFR 52.1470(c)(33). To clarify its status as 
an approved part of the Nevada SIP, we are proposing to revise 40 CFR 
52.1470(c)(33) to provide for a specific listing for section 33 
(Chlorine in Chemical Processes).
    SIP section 40, subsection 40.1, Prohibition of Nuisance 
Conditions; SIP section 42, subsection 42.2, untitled but related to 
nuisance from open burning; and SIP section 43, subsection 43.1, Odors 
in the Ambient Air. These three rules were submitted to EPA on July 24, 
1979. In 1981, we took final action on the portion of the July 24, 1979 
submittal that included these three rules. See 46 FR 43141 (August 27, 
1981). In that rulemaking, we indicated that we were taking no action 
on the three rules, but we inadvertently listed them as approved into 
the SIP. See 40 CFR 52.1470(c)(16)(viii). Therefore, we are proposing 
to revise 40 CFR 52.1470(c)(16)(viii) to delete SIP section 40, 
subsection 40.1 (Prohibition of Nuisance Conditions), SIP section 42, 
subsection 42.2 (untitled but related to nuisance from open burning), 
and SIP section 43, subsection 43.1 (Odors in the Ambient Air), 
submitted on July 24, 1979, from the Nevada SIP.
    Conclusion. EPA has reviewed the rules described above and 
determined that they were previously approved in

[[Page 31067]]

error into the Clark County portion of the Nevada SIP (SIP sections 
1.79, 1.94, 15, 29, 40.1, 42.2, and 43.1), or were previously 
disapproved but not clearly identified as such in the CFR (former SIP 
section 12 and disapproved submitted section 25.1), or were not clearly 
listed as approved (SIP section 33). Deletion of those rules approved 
in error into the SIP will not relax the applicable SIP and is 
consistent with the Act. Therefore, EPA is proposing to delete them and 
to clarify the status of the other listed rules under section 110(k)(6) 
of the Act, which provides EPA with the authority to take these actions 
without additional State submission.

III. Proposed Action and Public Comment

    As authorized under section 110(k)(3) of the Act, EPA is proposing 
a partial approval and partial disapproval of the revised Clark County 
NSR rules into the Nevada SIP. We are proposing to approve submitted 
DAQM sections 0, 11, 12 (except subsections 12.2.18 and 12.2.20), 58, 
and 59 and submitted State regulation NAC 445B.22083. We are proposing 
to disapprove submitted DAQM section 12, subsections 12.2.18 and 
12.2.20, and submitted DAQM section 52, subsection 52.8.
    If finalized, this action would incorporate those provisions of the 
submitted rules that we are approving into the SIP and would not 
incorporate those provisions that we are disapproving. Also, if 
finalized as proposed, the submitted rules will supercede the existing 
SIP rules that provide for permitting of new or modified stationary 
sources in Clark County, including all of existing SIP sections 11 and 
15, as well as most of the defined terms in existing SIP section 1, and 
will withdraw EPA's nonattainment area visibility FIP authority as it 
relates to new source review by DAQM in Clark County (see 40 CFR 
52.1488(b)). If this partial disapproval is finalized, sanctions will 
not be imposed under section 179 of the Act because the provisions that 
we are proposing to disapprove are not required SIP submissions.
    With respect to the two local rules entitled ``Definitions,'' if we 
finalize this action as proposed, we would approve submitted DAQM 
section 0 (Definitions) in its entirety, including those terms not 
directly related to NSR, but we would retain 33 defined terms from SIP 
section 1 (Definitions) because there are no equivalent, corresponding 
terms and definitions in DAQM section 0, and thus, these terms may be 
needed for existing SIP rules unaffected by this action. The 33 defined 
terms from SIP section 1 to be retained include: Affected Facility 
(1.1), Air Contaminant (1.3), Air Pollution Control Committee (1.6), 
Area Source (1.11), Atmosphere (1.12), Board (1.16), Commercial Off-
Road Vehicle Racing (1.23), Dust (1.26), Existing Facility (1.28), 
Existing Gasoline Station (1.29), Fixed Capital Cost (1.30), Fumes 
(1.36), Health District (1.40), Hearing Board (1.41), Integrated 
Sampling (1.44), Minor Source (1.50), Mist (1.51), New Gasoline Station 
(1.57), New Source (1.58), NIC (1.60), Point Source (1.70), Shutdown 
(1.78), Significant (unnumbered), Single Source (1.81), Smoke (1.83), 
Source of Air Contaminant (1.84), Special Mobile Equipment (1.85), 
Standard Commercial Equipment (1.87), Standard Conditions (1.88), Start 
Up (1.89), Stop Order (1.91), Uncombined Water (1.95), and Vapor 
Disposal System (1.97). The TSD provides additional information on the 
proposed partial supercession of existing SIP section 1.
    Second, in recognition of the vacature of our approval of previous 
versions of the Clark County NSR rules in Hall v. EPA, we propose to 
delete 40 CFR 52.1470(c)(36) and (37).
    Third, under section 110(k)(6), we are proposing to correct certain 
provisions of the Clark County portion of the Nevada SIP that were 
incorporated into the SIP in error and to revise certain provisions of 
the Clark County portion of the Nevada SIP that warrant clarification. 
Specifically, we are proposing to delete SIP section 1, subsections 
1.79 (Significant source of total chlorides'') and 1.94 (Total 
Chlorides); SIP section 15 (Prohibition of Nuisance Conditions); SIP 
section 29 (Odors in the Ambient Air); SIP section 40, subsection 40.1 
(Prohibition of Nuisance Conditions); SIP section 42, subsection 42.2 
(untitled but related to nuisance from open burning); and SIP section 
43, subsection 43.1 (Odors in the Ambient Air), from the appropriate 
paragraphs of section 1470 (``Identification of plan'') of 40 CFR part 
52, subpart DD (Nevada). If finalized as proposed, this action will 
delete these rules from the federally enforceable SIP. We are also 
proposing to revise the appropriate paragraphs in 40 CFR 52.1470 to 
clarify that former SIP section 12 (Upset, Breakdown, or Scheduled 
Maintenance) and submitted section 25.1 (untitled, but related to 
upset, breakdown, or scheduled maintenance) have been disapproved and 
are not approved into the Nevada SIP, and to clarify that SIP section 
33 (Chlorine in Chemical Processes) was, and continues to be, approved 
into the Nevada SIP as part of our approval of the overall post-1982 
ozone plan for Las Vegas Valley.
    We are soliciting public comment on all aspects of this proposal. 
These comments will be considered before taking final action. To 
comment on today's proposal, you should submit comments by mail (in 
triplicate if possible) as described in the ADDRESSES section listed in 
the front of this document. EPA will consider any written comments 
received by July 2, 2004.

IV. Statutory and Executive Order Reviews

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
proposed action is not a ``significant regulatory action'' and 
therefore is not subject to review by the Office of Management and 
Budget. For this reason, this action is also not subject to Executive 
Order 13211, ``Actions Concerning Regulations That Significantly Affect 
Energy Supply, Distribution, or Use'' (66 FR 28355, May 22, 2001). This 
proposed action merely proposes to approve state law as meeting Federal 
requirements and imposes no additional requirements beyond those 
imposed by state law. Accordingly, the Administrator certifies that 
this proposed rule will not have a significant economic impact on a 
substantial number of small entities under the Regulatory Flexibility 
Act (5 U.S.C. 601 et seq.). Because this rule proposes to approve pre-
existing requirements under state law and does not impose any 
additional enforceable duty beyond that required by state law, it does 
not contain any unfunded mandate or significantly or uniquely affect 
small governments, as described in the Unfunded Mandates Reform Act of 
1995 (Public Law 104-4).
    This proposed rule also does not have tribal implications because 
it will not have a substantial direct effect on one or more Indian 
tribes, on the relationship between the Federal Government and Indian 
tribes, or on the distribution of power and responsibilities between 
the Federal Government and Indian tribes, as specified by Executive 
Order 13175 (65 FR 67249, November 9, 2000). This action also does not 
have Federalism implications because it does not have substantial 
direct effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government, as specified 
in Executive Order 13132 (64 FR 43255, August 10, 1999). This action 
merely proposes to approve a state rule implementing a Federal 
standard, and does not alter the relationship or the

[[Page 31068]]

distribution of power and responsibilities established in the Clean Air 
Act. This proposed rule also is not subject to Executive Order 13045 
``Protection of Children from Environmental Health Risks and Safety 
Risks'' (62 FR 19885, April 23, 1997), because it is not economically 
significant.
    In reviewing SIP submissions, EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. In 
this context, in the absence of a prior existing requirement for the 
State to use voluntary consensus standards (VCS), EPA has no authority 
to disapprove a SIP submission for failure to use VCS. It would thus be 
inconsistent with applicable law for EPA, when it reviews a SIP 
submission, to use VCS in place of a SIP submission that otherwise 
satisfies the provisions of the Clean Air Act. Thus, the requirements 
of section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (15 U.S.C. 272 note) do not apply. This proposed rule does 
not impose an information collection burden under the provisions of the 
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Intergovernmental relations, Lead, Nitrogen dioxide, Ozone, Particulate 
matter, Reporting and recordkeeping requirements, Sulfur oxides, 
Volatile organic compound.

    Dated: May 24, 2004.
Laura Yoshii,
Acting Regional Administrator, Region IX.
[FR Doc. 04-12412 Filed 6-1-04; 8:45 am]
BILLING CODE 6560-50-P