[Federal Register Volume 60, Number 128 (Wednesday, July 5, 1995)]
[Rules and Regulations]
[Pages 34859-34867]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-16358]



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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 52 and 81

[NC-061-1-7010; FRL-5226-3]


Approval and Promulgation of Implementation Plans and Designation 
of Areas for Air Quality Planning Purposes; State of North Carolina

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is approving a maintenance plan and a request to 
redesignate the Charlotte-Gastonia area from nonattainment to 
attainment for ozone (O3) submitted on November 12, 1993, by the 
State of North Carolina through the North Carolina Department of 
Environment, Health, and Natural Resources. Subsequently on December 
16, 1994, January 6, 1995, and May 23, 1995, the State submitted 
supplementary information which included refined modeling and revisions 
to the maintenance plan. The Charlotte-Gastonia O3 nonattainment 
area includes Mecklenburg and Gaston Counties. EPA is also approving 
the State of North Carolina's 1990 baseline emissions inventory because 
it meets EPA's requirements regarding the approval of baseline emission 
inventories.

EFFECTIVE DATE: July 5, 1995.

ADDRESSES: Copies of the documents relative to this action are 
available for public inspection during normal business hours at the 
following locations. The interested persons wanting to examine these 
documents should make an appointment with the appropriate office at 
least 24 hours before the visiting day.

Air and Radiation Docket and Information Center (Air Docket 6102), U.S. 
Environmental Protection Agency, 401 M Street, SW, Washington, DC 
20460.
Environmental Protection Agency, Region 4 Air Programs Branch, 345 
Courtland Street, NE, Atlanta, Georgia 30365.
State of North Carolina, Air Quality Section, Division of Environmental 
Management, North Carolina Department of Environment, Health, and 
Natural Resources, Raleigh, North Carolina 27626.
Environmental Management Division, Mecklenburg County Department of 
Environmental Protection, 700 N. Tryon Street, Charlotte, North 
Carolina 28202-2236.

FOR FURTHER INFORMATION CONTACT: Kay Prince, Regulatory Planning and 
Development Section, Air Programs Branch, Air, Pesticides & Toxics 
Management Division, Region 4 Environmental Protection Agency, 345 
Courtland Street, NE, Atlanta, Georgia 30365. The telephone number is 
404/347-3555 extension 4221. Reference file NC-061-1-6815.

SUPPLEMENTARY INFORMATION: On November 15, 1990, the Clean Air Act 
Amendments of 1990 were enacted. (Pub. L. 101-549, 104 Stat. 2399, 
codified at 42 U.S.C. 7401-7671q). Under section 107(d)(1)(C), EPA 
designated Mecklenburg County of the Charlotte-Gastonia area as 
nonattainment by operation of law with respect to O3 because the 
area was designated nonattainment immediately before November 15, 1990. 
The nonattainment area was expanded to include Gaston County per 
section 107(d)(1)(A)(i) (See 56 FR 56694 (Nov. 6, 1991) and 57 FR 56762 
(Nov. 30, 1992), codified at 40 CFR 81.318.) The area was classified as 
moderate.
    The moderate nonattainment area had ambient monitoring data that 
showed no violations of the O3 NAAQS, during the period from 1990 
through 1993. Therefore, on November 12, 1993, the State of North 
Carolina submitted an O3 maintenance plan and requested 
redesignation of the area to attainment with respect to the O3 
NAAQS. The O3 NAAQS continues to be maintained in the Charlotte-
Gastonia area. On January 24, 1994, Region 4 determined that the 
information received from the State constituted a complete 
redesignation request under the general completeness criteria of 40 CFR 
51, appendix V, sections 2.1 and 2.2. Subsequently, on December 16, 
1994, and January 6, 1995, the State submitted additional information 
that refined the modeling and clarified the future measures needed to 
ensure maintenance of the O3 NAAQS. The State requested the 
January 6, 1995, information be parallel processed by EPA. The State 
held a public hearing on April 19, 1995, and made a final submittal to 
EPA on May 23, 1995.
    The North Carolina redesignation request for the Charlotte-Gastonia 
moderate O3 nonattainment area meets the five requirements of 
section 107(d)(3)(E) for redesignation to attainment. The following is 
a brief description of how the State of North Carolina has fulfilled 
each of these requirements. Because the maintenance plan is a critical 
element of the redesignation request, EPA will discuss its evaluation 
of the maintenance plan under its analysis of the redesignation 
request.

1. The Area Must Have Attained the O3 NAAQS

    The State of North Carolina's request is based on an analysis of 
quality assured ambient air quality monitoring data, which is relevant 
to the maintenance plan and to the redesignation request. Most recent 
ambient air quality monitoring data for calendar year 1990 through 
calendar year 1994 demonstrates attainment of the standard. The State 
of North Carolina has committed to continue monitoring the moderate 
nonattainment area in accordance with 40 CFR 58. Therefore, the State 
has met this requirement. For detailed information refer to the 
proposed document published April 17, 1995 (60 FR 19197). 

[[Page 34860]]


2. The Area Has Met All Applicable Requirements Under Section 110 
and Part D of the CAA

    EPA reviewed the North Carolina SIP and ensures that it contains 
all measures due under the amended CAA prior to or at the time the 
State of North Carolina submitted its redesignation request. For 
detailed information regarding applicable requirements other than 
section 182(f), refer to the proposed document.
A. Section 182(a)(1)--Emissions Inventory

    North Carolina has met this requirement. This document gives final 
approval of the 1990 base line emissions inventory. For detailed 
information regarding how this requirement was met, refer to the 
proposal document.

B. Section 182(a)(2), 182(b)(2)--Reasonably Available Control 
Technology (RACT)

    As stated in the proposal document, North Carolina had met all RACT 
requirements except those in 182(b)(2), RACT Catch-ups. On January 7, 
1994, the State submitted revisions to the SIP that addressed the RACT 
Catch-ups. The document approving those revisions was published on 
January 26, 1995 (see 60 FR 5138), and became effective on March 27, 
1995. Therefore this requirement has been met. For detailed information 
regarding this requirement, refer to the proposal document.

C. Section 182(a)(3)--Emissions Statements

    In the proposal document, EPA stated that the North Carolina 
Emissions Statement regulation must be approved prior to or at the time 
of redesignation. On December 17, 1993, North Carolina submitted a 
revision to the SIP that met the requirements for an emission statement 
regulation. The document approving this revision was published on May 
5, 1995 (see 60 FR 22284). No adverse comments were received, 
therefore, the effective date of the federal approval is July 5, 1995. 
Therefore this requirement has been met. For detailed information 
regarding this requirement, refer to the proposal document.

D. Section 182(b)(1)--15% Progress Plans

    With the approval of this redesignation request, the requirement to 
submit a 15% plan is obviated because the redesignation request 
predated the requirement for a 15% plan. Additionally, on May 10, 1995, 
EPA, in a memorandum from John S. Seitz, Director, Office of Air 
Quality Planning and Standards, issued a new policy regarding planning 
requirements of the CAA. Areas that have quality assured air monitoring 
data showing attainment with the ozone standard for the most recent 
three years are deemed to have attained the standard and such are not 
subject to certain requirements of subpart 2 of Part D of title I of 
the CAA. Specifically, a moderate area such as Charlotte-Gastonia would 
no longer be required to submit a 15% plan or an attainment 
demonstration. EPA has published a document making such finding with 
respect to the Charlotte-Gastonia area. See the proposal document for 
more detailed information.

E. Section 182(b)(3)--Stage II

    On January 24, 1994, EPA promulgated the onboard vapor recovery 
rule (OBVR), and, section 202(a)(b) of the CAA provides that once the 
rule is promulgated, moderate areas are no longer required to implement 
Stage II. Thus, the Stage II vapor recovery requirement of section 
182(b)(3) is no longer an applicable requirement. See the proposal 
document for more detailed information.

F. Section 182(b)(4)--Motor Vehicle Inspection and Maintenance (I/M)

    In the proposal document, EPA stated that the North Carolina I/M 
regulation must be approved prior to or at the time of redesignation. 
On July 19, 1993, North Carolina submitted a revision to the SIP that 
met the requirements for an I/M regulation. The document approving this 
revision was published on June 2, 1995 (see 60 FR 28720), and the 
revision is federally approved. For detailed information regarding this 
requirement, refer to the proposal document.

G. Section 182(b)(5)--New Source Review (NSR)

    North Carolina has a fully-approved NSR program for moderate 
O3 nonattainment areas. For detailed information regarding this 
requirement, refer to the proposal document.

H. Section 182(f)--Oxides of Nitrogen (NOX) Requirements

    This redesignation request predated the November 15, 1993, 
requirement for the submittal of NOX RACT rules. Therefore, 
NOX RACT is not an applicable requirement for purposes of this 
redesignation request. However, the State has submitted revisions that 
would require NOX RACT should the area violate the O3 NAAQS. 
This submittal pre-adopts NOX RACT rules as a contingency measure. 
Since contingency measures for maintenance are not required to be pre-
adopted, approval of this submittal is not a requirement for 
redesignation. Action on that submittal will be taken in another 
document since it is not an applicable requirement for purposes of this 
redesignation request. For more detailed information regarding this 
requirement, refer to the proposal document.

3. The Area Has a Fully Approved SIP Under Section 110(k) of the 
CAA

    Based on the approval of provisions under the pre-amended CAA and 
EPA's prior approval of SIP revisions under the amended CAA, EPA has 
determined that the Charlotte-Gastonia area has a fully approved 
O3 SIP under section 110(k).

4. The Air Quality Improvement Must Be Permanent and Enforceable

    Several control measures have come into place since the Charlotte-
Gastonia nonattainment area violated the O3 NAAQS. Of these 
control measures, the reduction of fuel volatility from 10.6 psi in 
1987 to less than 9.0 psi in 1990, and finally to less than 7.8 psi 
beginning with the summer of 1992, as measured by the Reid Vapor 
Pressure (RVP), and fleet turnover due to the Federal Motor Vehicle 
Control Program (FMVCP) produced the most significant decreases in VOC 
emissions. The reduction in VOC emissions due to the mobile source 
regulations from 1987 to 1990 is 26.01 tons per day (29.63%). The VOC 
emissions in the base year are not artificially low due to a depressed 
economy.

5. The Area Must Have a Fully Approved Maintenance Plan Pursuant to 
Section 175A of the CAA

    Section 175A of the CAA sets forth the elements of a maintenance 
plan for areas seeking redesignation from nonattainment to attainment. 
The plan must demonstrate continued attainment of the applicable NAAQS 
for at least ten years after the Administrator approves a redesignation 
to attainment. Eight years after the redesignation, the state must 
submit a revised maintenance plan which demonstrates attainment for the 
ten years following the initial ten-year period. To provide for the 
possibility of future NAAQS violations, the maintenance plan must 
contain contingency measures, with a schedule for implementation, 
adequate to assure prompt correction of any air quality problems.
    EPA is approving the State of North Carolina's maintenance plan for 
the Charlotte-Gastonia nonattainment area 

[[Page 34861]]
because EPA finds that the State's submittal meets the requirements of 
section 175A.

A. Emissions Inventory

a. Base Year Inventory
    On November 13, 1992, the State of North Carolina submitted 
comprehensive inventories of VOC, NOX, and carbon monoxide (CO) 
emissions from the Charlotte-Gastonia nonattainment area. The inventory 
included biogenic, area, stationary, and mobile sources for 1990.
    The State of North Carolina submittal contains the detailed 
inventory data and summaries by county and source category. Finally, 
this inventory was prepared in accordance with EPA guidance. This 
action approves the final base year inventory for the Charlotte-
Gastonia area. A summary of the base year inventory is included in the 
table below.

 1990 Charlotte/Gastonia Typical Summer Day Emissions Tons per Day (TPD)
------------------------------------------------------------------------
                   Category                      NOX      VOC       CO  
------------------------------------------------------------------------
Point........................................    31.25    33.99    35.27
Area.........................................     4.92    67.59    25.00
Non-road.....................................    15.52    19.38   138.45
Biogenic.....................................     2.78    54.41     0   
Mobile.......................................    61.64    50.81   371.26
                                              --------------------------
  Total......................................   116.11   226.18   569.98
------------------------------------------------------------------------

b. Emission Budget for Conformity
    EPA's transportation conformity regulation requires that states 
adopt an emissions budget for conformity for ozone precursors in 
maintenance areas. Therefore, the State of North Carolina has adopted 
the following emissions budget:

                       Conformity Emissions Budget                      
------------------------------------------------------------------------
                               1999 NOX   1999 VOC   2005 NOX   2005 VOC
   Source cat. and county       (TPD)      (TPD)      (TPD)      (TPD)  
------------------------------------------------------------------------
Mobile:                                                                 
    Mecklenburg.............       33.5       25.5       33.0       25.9
    Gaston..................        9.3        6.3        8.7        5.7
Point:                                                                  
    Mecklenburg.............        2.6       23.0        2.8       24.3
    Gaston..................       79.5        7.3       79.7        7.5
Area:                                                                   
    Mecklenburg.............        3.7       23.0        3.9       33.3
    Gaston..................        1.3       16.7        1.4       16.5
Non-road:                                                               
    Mecklenburg.............       18.6       20.2       17.8       22.5
    Gaston..................        4.8        5.6        4.1        5.8
------------------------------------------------------------------------

    EPA will be taking separate rulemaking action on conformity 
emission budgets.

B. Demonstration of Maintenance--Urban Airshed Modeling

a. Control Strategy
    The plan must demonstrate maintenance for at least 10 years. The 
North Carolina plan demonstrates maintenance out to the year 2005 
through the use of the Urban Airshed Model (UAM). On December 16, 1994 
and January 6, 1995, the State submitted a revision to the original 
maintenance plan submitted to EPA on November 12, 1993, requesting that 
EPA parallel process the revisions. These submittals which included 
revisions to the modeling pursuant to EPA comment and additional 
corrections to the modeling were presented at the public hearing held 
in Charlotte on April 19, 1995. The modeling analysis included base and 
future case modeling completed according to guidelines presented in the 
EPA document ``Guideline for Regulatory Application of the Urban 
Airshed Model.'' The future case modeling includes the interim year 
1999 and the 10 year maintenance year of 2005. This modeling analysis 
did not assume any benefit from the NSR program.
    Modeling for all three episodes predicted a small number of grid 
cells (< 1 %) above .124 parts per million (ppm) for both 1999 and 
2005, with the maximum level predicted of .129 ppm. The analysis of 
control options showed that NOX controls would be more effective 
in the maintenance of the standard in the Charlotte/Gastonia area, and, 
hence, the State originally selected a strategy that consisted 
primarily of additional controls of NOX emissions. The selected 
control strategy included the following measures:
     Reformulated Gasoline to meet the Federal Phase I and 
Phase II standards to begin in 1999 in Mecklenburg, Gaston, Union, 
Cabarrus, Lincoln, Rowan, and Iredell Counties;
     Clean Fuel Fleet Program, including the schedule for 
implementation as specified in the CAA for areas classified serious and 
above, in the same seven counties previously listed;
     Burning bans in the seven counties for the months of June, 
July, and August;
     Control of NOX for the Transcontinental Natural Gas 
Pumping Station in Iredell County for the months of June, July, and 
August; and
     Additional 10 percent control beyond the control being 
applied to meet title IV NOX requirements on Duke Power's Allen 
and Riverbend facilities in Gaston County for the months of June, July, 
and August.
    The State also took comment at the public hearing on the 
feasibility of substituting an enhanced I/M program for the 
reformulated gasoline measure. The modeling results indicate that such 
substitution would show maintenance of the standard. After 
consideration of the comments at the public hearing, the North Carolina 
Environmental Management Commission adopted the maintenance plan 
without additional controls on May 11, 1995.

2. Request for Comments

    As requested by the State, EPA is parallel processing the request 
and therefore published a document on April 17, 1995, proposing 
approval of the maintenance plan and redesignation request and 
soliciting comment on the following control scenarios: 

[[Page 34862]]

    a. Adoption and implementation in 1999 of the five measures as 
detailed above;
    b. Adoption and implementation in 1999 of the five measures as 
detailed above with enhanced I/M substituted for the reformulated 
gasoline program;
    c. Adoption and implementation in 1999 of the aforementioned 
controls on the Transcontinental Natural Gas Pumping Station in Iredell 
County and the additional 10 percent control beyond the title IV 
requirements on Duke Power's Allen and Riverbend facilities in Gaston 
County; or
    d. Approval of the request as demonstrating maintenance with no 
additional VOC or NOX controls.
    EPA received a number of comments on the proposal and the control 
scenarios. Those comments and the response thereto are summarized 
below.
    Comment #1--Rather than controlling emissions, the plan allows an 
increase in NOX emissions of 25 tons per day by 1999 in the 
nonattainment area and additional increases throughout the modeling 
domain.
    Response--Section 175A of the CAA requires that a plan showing 
maintenance of the applicable NAAQS for 10 years after redesignation be 
incorporated as revision to the SIP. In a September 4, 1992, memorandum 
from John Calcagni, Director, Air Quality Management Division, EPA 
issued guidance on the requirements for redesignation of areas from 
nonattainment to attainment. That guidance contains two primary methods 
a state may use to demonstrate maintenance of the O3 NAAQS for an 
area. The first method is an emissions inventory demonstration which 
includes emission projections showing no increases in emissions of 
O3 precursors, i.e., NOX and VOC, in the designated 
nonattainment area throughout the 10 year maintenance period. This 
method would not allow the projected increase in emissions of NOX 
in the nonattainment counties. The second method is a modeling 
demonstration showing that the projected levels of emissions of O3 
precursors would not cause a violation of the NAAQS. The guidance 
further stipulates that the level of modeling required must be at least 
that required by the CAA for an attainment demonstration for the area. 
Since the Charlotte-Gastonia area is a moderate intra-state area, the 
level of modeling required would have been EKMA or its equivalent. 
However, the State of North Carolina chose to use the UAM model which 
is required for inter-state moderate areas as well as serious and above 
areas.
    For the reasons explained in the proposal and in the responses to 
comments on the modeling provided below, EPA believes that the modeling 
demonstration, which evaluated a strategy with a combination of 
decreases in VOC emissions and increases in NOX emissions, 
submitted by the State of North Carolina adequately demonstrated 
maintenance of the NAAQS notwithstanding the projected increase in 
NOX emissions. Therefore, EPA believes that the increases in 
NOX emissions are permissible.
    Comment #2--Concern was expressed regarding the emission increases 
projected for Duke Power sources located in the area. It was suggested 
that for equity, Duke Power should be required or provided incentives 
to install additional emission controls.
    Response--The Duke Power plants in question are subject to EPA's 
acid rain provisions and reductions in NOX emissions will be 
obtained from this program. Neither the CAA nor the EPA require a 
specific set of measures to ensure maintenance of the O3 NAAQS, 
but rather the state determines for each area what additional 
reductions, if any, are necessary. The EPA then determines the adequacy 
of the plan. EPA has determined, as explained elsewhere, in this 
document and the proposal, that the existing control system is adequate 
to ensure maintenance of the NAAQS for ten years.
    Comment #3--North Carolina has consistently stated that additional 
controls are necessary to maintain the standard and that controls on 
sources of NOX emissions are the most effective.
    Response--The State's assertion that additional NOX controls 
would be necessary to maintain the NAAQS after 1999 was based on the 
UAM modeling and the view that every grid cell must be below the 
standard in order to demonstrate maintenance. However, EPA has 
determined, as discussed in the proposal and elsewhere in this 
document, that the State's modeling demonstration adequately 
demonstrates maintenance of the NAAQS without additional control 
measures.
    Comment #4--Monitored daily maximum ozone concentrations over the 
last five years indicate that the nonattainment area has been on the 
verge of violating the O3 NAAQS. Furthermore, the modeling 
predicts future exceedances of the NAAQS for all three episodes.
    Response--Although two monitors in the ozone nonattainment area and 
one monitor in an adjacent county recorded two exceedances of the 
O3 NAAQS in 1993, there have been no violations of the NAAQS in 
the last five years. Furthermore, there were no exceedances recorded at 
any monitor in the area in 1992 or 1994. An area is allowed one 
exceedance of the NAAQS per year with a three year average used to 
determine attainment/nonattainment status. Therefore, since the 
expected exceedance rate for the area is 0.67 which is less than 1.1 
and since all monitors are currently monitoring attainment of the 
NAAQS, EPA believes that the monitoring data is sufficient to support 
redesignation of the area to attainment. EPA's Response to the comments 
regarding the modeling is contained in EPA's Response to Comment #5.
    Comment #5--One Commenter provided detailed Comments individually 
on each of the six items listed in the proposal as support for EPA's 
determination that the modeling demonstration is sufficiently 
conservative for EPA to conclude that the NAAQS can be maintained 
without additional emission controls. In the proposal, EPA explained 
that while its modeling guidance generally requires that modeling 
results show attainment of the standard in all grid cells, it does 
allow alternative methods for demonstrating attainment on a case-by-
case basis. EPA went on to explain its belief that North Carolina's 
modeling for the Charlotte-Gastonia area was sufficiently conservative 
to provide an adequate demonstration of maintenance without the 
adoption of additional controls notwithstanding the model's prediction 
of slight exceedances of the standard in a few grid cells. That belief 
was based on the combination of the following six factors:
    (1) North Carolina has five years of air quality data showing 
attainment of the standard.
    (2) The maintenance plan contains pre-adopted measures and a 
violation would trigger reduction in emissions by the following O3 
season.
    (3) The O3 standard is a statistically based NAAQS that allows 
one exceedance per year.
    (4) North Carolina has done extensive modeling to gain an 
understanding of the creation of O3 in the Charlotte area and has 
generally made conservative assumptions in selecting modeling inputs.
    (5) The uncertainties in the biogenic emission inventory and other 
modeling inputs are well within the range of the 2-3 ppb needed to 
reach the .124 ppm in all grid cells.
    (6) The modeling did not account for lower VOC, NOX and 
O3 boundary conditions expected when SIP attainment and title IV 
(acid rain program) control programs have been 

[[Page 34863]]
implemented in many areas throughout the United States.
    This commenter took issue with each of the six factors that EPA 
referenced in the proposal.
    Response--Before responding to the comments on each of the six 
factors individually, EPA notes that, as indicated in the proposal, it 
was the combination of factors--not necessarily any particular factor 
standing alone--that supports EPA's determination that the modeling 
provides an adequate demonstration that the ozone NAAQS will be 
maintained in the absence of the adoption of additional control 
measures. Furthermore, as explained below, the Comments made with 
respect to each of the factors individually fail to undermine the 
validity of EPA's conclusion that the modeling provides an adequate 
demonstration of maintenance. Although the commenter made relevant 
points, EPA believes that when considered together, on balance the 
factors support the conclusion that North Carolina has adequately 
demonstrated that the Charlotte-Gastonia area will maintain the 
standard.
    (1) North Carolina has five years of air quality data showing 
attainment of the standard.
    With three years of air quality showing attainment an area can 
request redesignation. North Carolina's request is strengthened by the 
fact that it has five years of air quality data showing no violations 
of the O3 NAAQS.
    Based upon a trend analysis performed by EPA, meteorologically 
adjusted O3 trends in Charlotte (and surrounding areas) have shown 
a modest but consistent improvement of approximately 1 percent per year 
between 1983 and 1993. However, the most recent five years analyzed 
(1988-1993) have shown an accelerated rate of improvement of 
approximately 2 to 3 percent per year (10 percent over the five year 
period) suggesting that recent ozone air quality is improving when 
meteorological conditions are eliminated.
    Moreover, EPA has conducted an analysis of the O3 potential in 
the major urban areas, including Charlotte, using available 
meteorological data collected over the past 41 years. The study 
(currently undergoing review for publication in Atmospheric 
Environment), indicates that meteorological conditions favoring high 
O3 ranked the summer of 1993 as the 2nd most severe O3 year 
in the past 41 years. The two years, 1988 and 1987 were ranked 7th and 
4th, respectively. The meteorology for all three years was very 
conducive to producing high O3 concentrations. Since North 
Carolina did not have a violation in 1993 under meteorological 
conditions of comparable severity to the 1988 and 1987 modeling 
analyses, this supports the redesignation demonstration.
    Although NOX emissions are projected to increase over the 
maintenance period, i.e. from the 1990 base line inventory, the State 
of North Carolina's experience in other similar areas (Raleigh/Durham 
and Greensboro/Winston-Salem) suggests that total NOX emissions in 
1999 will be less than 1993. Specifically, the projected emissions from 
the three area power plants in 1999 that are the area's primary 
NOX sources are less than the actual emissions from those plants 
in 1993. Since the area was able to maintain the standard despite the 
higher NOX emissions and adverse meteorological conditions in 
1993, it would be expected that the projected decrease in power plant 
emissions would support the ability for the area to continue to 
maintain the O3 NAAQS.
    (2) The maintenance plan contains pre-adopted measures and a 
violation would trigger reduction in emissions by the following ozone 
season. While it is true that the presence of pre-adopted measures in 
the maintenance plan triggered by a violation does not make the 
modeling analysis conservative, it does add strength to the package as 
a whole and will allow the State to implement new controls to quickly 
address any future nonattainment problem. The State has done 
preliminary modeling analysis on both the pre-adopted and the other 
contingency measures listed in the plan which will assist the State in 
timely implementation of the most effective measures.
    Additionally, the contingency plan contains a secondary trigger 
which is an exceedance of the ozone standard that would indicate a 
violation could be imminent. This trigger will be activated within 30 
days of the State finding the exceedance. Once the secondary trigger is 
activated, the State Air Quality Section will commence analysis, 
including updated modeling as necessary, to determine what control 
measures will be required to keep the area in attainment, with the 
regulatory adoption process for any necessary measures beginning by May 
1 of the following year. As the contingency measures based on the 
secondary trigger should help the area stay in attainment, those 
measures should also help the area maintain the standard and do provide 
an additional level of assurance that the area will maintain the 
standard.
    (3) The O3 standard is a statistically based NAAQS that allows 
one exceedance per year.
    Developing an attainment test using gridded concentrations for a 
few selected days to match a NAAQS determination which uses sparsely 
located monitors for a complete hourly O3 season is not simple. 
Recognizing the severity of O3 forming potential for selected 
episodes, as well as the NAAQS allowing one exceedance at each monitor 
location over a three year period, led EPA to consider how stringent 
the model test of requiring every grid cell modeled across the domain 
to be below 124 ppb for all hours might be. Again, based on the 
severity of the years modeled, EPA believes the modeling demonstration 
indicates that a few grid cells would exceed 124 ppb by a slight amount 
(less than 1% with a maximum value of 129 ppb) is within a margin of 
safety that the NAAQS will be maintained provided the contingency 
measures in the plan are identified and implemented, if the need is 
indicated by monitored data. As indicated previously, the State's plan 
contains a secondary trigger for contingency measures based on an 
exceedance of the O3 NAAQS that would indicate a violation is 
imminent.
    (4) North Carolina has done extensive modeling to gain an 
understanding of the creation of O3 in the Charlotte area and has 
generally made conservative assumptions in selecting modeling inputs.
    EPA recognizes and allows for uncertainty in model estimates as 
part of the model performance evaluation conducted prior to use in 
strategy development. EPA guidance includes recommended ranges for 
statistical performance measures. For the North Carolina application, 
although model estimates were sometimes below the observed highest 
concentrations (base case), overall the performance results suggest 
that UAM is unbiased and is therefore expected to produce unbiased 
estimates of future air quality assuming unbiased (non-conservative) 
estimates of future emissions and boundary conditions are used.
    In fact, North Carolina was conservative in its choice of model, 
years to simulate, boundary conditions and emissions growth factors. 
Although, North Carolina was not required to do so, it chose to use UAM 
so as to better understand and quantify the effect of ozone precursors 
in the area and thus identify the most cost effective strategy for 
maintaining the NAAQS. EPA believes North Carolina did select years 
that are conducive to high levels of O3 (also see discussion 
above) and chose 

[[Page 34864]]
episodes for which some of the highest O3 levels were observed in 
the area. North Carolina used boundary concentrations along the North 
Carolina domain that were only reduced by 5 percent (O3, NOX, 
and VOC) so that the maximum level of ozone was 120 ppb for the July 
1988 northerly transport episode. It is quite likely that the combined 
effect of VOC/NOX controls throughout the eastern U.S. will result 
in O3 boundary levels that are below those used in this modeling 
exercise. Finally, North Carolina used the 1990 BEA growth factors to 
project emissions. These factors were derived before the CAA mandated 
controls were implemented and do not take into consideration changes in 
business behavior that has occurred as companies have applied 
expenditures towards control measures rather than expansion. Also, the 
6 year window, 1988-93, used to estimate VMT growth includes very high 
growth years and the area is not expected to continue to grow at that 
rate. If the State had elected to use lower boundary conditions and 
lower growth rates, as allowed by EPA guidelines, it is likely that the 
modeling would have predicted ozone levels of 124 ppb or below in all 
grid cells.
    (5) The uncertainties in the biogenic emissions inventory and other 
modeling inputs are well within the range of the 2-5 ppb needed to 
reach 124 ppb in all grid cells.
    (The sentence above, as included in the proposal document, 
contained a typographical error, as it read ``* * * the range of the 2-
3 ppb * * *.'')
    As discussed in the response to item (4) above, North Carolina made 
very conservative assumptions on model inputs for the NC application 
which are within the 2-5 ppb reductions needed to reach 124 ppb. Based 
on EPA guidance, North Carolina used the most current and only 
regulatory version of the biogenic model available to states at the 
time of its modeling analyses. The new version of the biogenic model, 
BEIS2, is just now being released for use by states. The impact of the 
new model on O3 predictions is still being evaluated. The State of 
North Carolina has a commitment to perform modeling analyses in the 
future and will use the most current methodologies for all modeling 
inputs including BEIS as well as the most current model.
    (6) The modeling did not account for lower VOC, NOX and 
O3 boundary conditions expected when SIP attainment control 
programs have been implemented in many areas through the United States.
    Contrary to the assertions of the commenter, boundary conditions 
are relevant to modeling episodes for Charlotte. North Carolina modeled 
two transport episodes and one stagnation episode. As indicated above, 
conservative assumptions on boundary conditions were made for the July 
1988 transport episode. The boundary conditions for the other two 
episodes, including the stagnation episode, were not reduced. As states 
and the Environmental Council of States (ECOS) embark on the Phase II 
modeling efforts, North Carolina is within the regional domain being 
evaluated. If regional or more local controls appear warranted based on 
new analysis, North Carolina will be notified and EPA is confident that 
the State will work with EPA (using better information as it becomes 
available) to make any adjustment needed to maintain the NAAQS in the 
Charlotte area.
    Comment #6--The maintenance plan was developed without regard for 
the potential effects on the Southern Appalachian Mountains despite 
North Carolina's commitment to the Southern Appalachian Mountain 
Initiative (SAMI).
    Response--The Charlotte-Gastonia modeling analysis was not 
specifically designed to evaluate the effects of the plan on the 
Southern Appalachian Mountains. Only the O3 inputs in the 
Charlotte-Gastonia airshed were required for analysis of the 
redesignation of the Charlotte-Gastonia area. The meteorological 
episodes modeled for the redesignation request, while significant for 
O3 formation in the Charlotte-Gastonia area, do not include a 
situation where emissions from the Charlotte-Gastonia area are 
transported into the mountain region, which is currently in attainment 
and is not adjacent to the Charlotte-Gastonia area. Additionally, 
approval of this maintenance plan and redesignation request does not 
preclude additional controls being required on the sources in the 
Charlotte-Gastonia area as a result of future analysis indicating that 
such controls are necessary to protect air quality in the mountain 
region. In the event such controls are found to be necessary, EPA has 
the authority under section 110(b)(2) to require the adoption of 
control measures if the State fails to do so.
    Comment #7--There were several comments regarding the proposal by 
the State to require Phase II reformulated gasoline (RFG) in a seven 
county area beginning in 1999. The commenters noted that since the CAA 
requires Phase II RFG in some areas beginning in 2000, that the fuel 
may not be available in 1999. Furthermore, several commenters indicated 
their belief that an enhanced I/M program would be of greater benefit 
at a lower cost in controlling ozone.
    Response--As the maintenance plan approved by EPA in this final 
action does not include either Phase II RFG or enhanced I/M as a 
measure for maintenance of the NAAQS, issues regarding the use of Phase 
II RFG or enhanced I/M as maintenance measures are no longer pertinent.
    Comment #8--It was commented that the contingency plan should not 
include a list of specific options in the maintenance plan and that 
contingency measures should not be pre-adopted.
    Response--While the commenter is correct that contingency measures 
do not have to be pre-adopted, a state may chose whether or not to pre-
adopt any or all of the listed contingency measures. However, EPA 
policy does require that the maintenance plan include a list of 
possible contingency measures and a schedule for implementing those 
measures that are determined to be necessary to ensure continued 
maintenance of the NAAQS. EPA's policy is based on section 175A, which 
requires that maintenance plans ``contain such contingency provisions 
as the Administrator deems necessary to assure that the state will 
promptly correct any violation of the standard which occurs after'' 
redesignation. In any event, the State did not include additional pre-
adopted measures in the final submittal.
    Comment #9--The secondary trigger should be eliminated because it 
is vague and would raise questions about federal enforceability. 
Additionally, one commenter believes interpretation that an exceedance 
of the NAAQS should cause a contingency measure to be adopted is too 
stringent.
    Response--While EPA policy and section 175A require only that a 
maintenance plan contain contingency measures triggered by a violation 
of a NAAQS, EPA has encouraged states to select triggers based on 
events short of a violation in order to prevent violations from 
occurring so that the area continues to maintain the NAAQS or to bring 
the area back into attainment more quickly should a violation occur 
after the trigger event has occurred. For example, the September 4, 
1992, memorandum from John Calcagni suggests that states use indicators 
such as monitoring, modeling and inventory levels to identify when 
early action may prevent a violation.
    The secondary trigger in the Charlotte-Gastonia maintenance plan is 
used as an alert for the State that action may be needed to ensure 
continued maintenance of the NAAQS. The resulting analysis may or may 
not 

[[Page 34865]]
indicate additional controls are needed. This mechanism is perfectly 
consistent with the purpose of a maintenance plan which is to ensure 
continued maintenance of the NAAQS. EPA believes that the use of the 
secondary trigger will help North Carolina not only to bring the area 
back into attainment quickly but to also prevent violations from 
occurring.
    EPA does not believe the use of an exceedance of the NAAQS as an 
indicator which may lead to additional controls causes an enforcement 
problem. Under 40 CFR 51.110, states are required to develop control 
strategies for the attainment and maintenance of NAAQS. These 
strategies must provide for both the attainment of the standards in 
nonattainment areas and the maintenance of those standards in 
attainment areas. Since NOX and VOC are defined as precursors to 
O3, a criteria pollutant for which there is a NAAQS, emission 
reductions of NOX and/or VOC are federally enforceable in 
attainment areas provided they are part of the federally-approved SIP. 
As the CAA requires SIPs for areas redesignated to attainment to 
include measures necessary to maintain the NAAQS, emission reductions 
required for maintenance of the standard in the future would be 
federally enforceable.
    Comment #10--If contingency measures are triggered in the near-term 
(i.e., before 2003), additional modeling should not be required unless 
there has been a significant change in the model inputs and 
assumptions.
    Response--North Carolina's contingency plan states that additional 
analysis will be done if necessary. Therefore, such analysis is not 
required, but is within the State's discretion to do if there have been 
significant changes in model inputs and assumptions or control 
technology to warrant a new analysis. EPA believes the contingency plan 
is approvable as written as it provides adequate assurance that 
violations will be corrected promptly in accordance with section 175A.
    Comment #11--The contingency options from which the State could 
choose should continue to include RFG or enhanced I/M, clean fuel fleet 
provisions, open burning restrictions, summer NOX controls from 
Transcontinental Gas Pipe Line Corporation and 10% beyond title IV from 
Duke Power's Riverbend and Allen plants during the summer. In addition, 
NOX and possibly VOC RACT should be available as contingency 
measures.
    Response--The final submittal from the State includes in their list 
of possible contingency measures additional NOX and VOC RACT or 
greater controls on sources, particularly Duke Power and 
Transcontinental Gas Pipe Line Corporation, Stage II vapor control, 
RFG, enhancements to the I/M program, clean fuel fleets and any other 
measures that may be appropriate and feasible. The State also indicated 
it intends to develop an economic incentive program that would provide 
incentives to sources that purchase clean alternative vehicles. 
Although the State could not adopt RFG rules without receiving a 
section 211(c)(1) waiver of preemption from EPA, EPA believes that 
North Carolina has identified an adequate and appropriate list of 
contingency measures in light of the numerous measures it has listed.
    Comment #12--The time schedule provisions of section 181(b) of the 
CAA are equally applicable to stationary and mobile sources. If 
contingency measures are needed in the future, the time schedules of 
the CAA should not be preferentially offered to mobile sources unless 
stationary sources have the same option.
    Response--Stationary source controls can often be implemented on a 
faster time frame than mobile source controls. It is generally clear 
what sources are subject to such rules and what is required for a 
source to comply. Mobile source measures are more difficult to develop 
and implement as there is a greater need for public education on mobile 
related programs. They also often take more time to implement. One of 
the primary considerations for choosing a contingency measure to 
implement is the time needed to develop, adopt and implement the 
measures necessary to prevent or correct a NAAQS violation. If the 
analysis shows that stationary sources play an important role in such a 
strategy, then implementation should be achieved as soon as possible.
    Comment #13--The contingency plan should provide the State with the 
flexibility to implement all, or any subset, of the above contingency 
measures as a first round of controls, if needed. However, once one of 
the contingency measures has been chosen and activated from the above 
list, no additional controls would be imposed on that category of 
sources until the other first round contingency control options have 
been activated. If a second round is required, than modeling should be 
used to develop a new balanced and cost-effective strategy.
    Response--The primary purpose of the contingency plan is to bring 
an area back into attainment should the area violate the NAAQS after 
redesignation. The choice of which measures to implement lies with the 
state so long as the measures from which the state is choosing are 
effective. The North Carolina contingency plan provides the State with 
adequate flexibility to enact the measures which will be most effective 
in returning the area to attainment.

C. Verification of Continued Attainment

    Continued attainment of the O3 NAAQS in the nonattainment area 
depends, in part, on the State of North Carolina's efforts toward 
tracking indicators of continued attainment during the maintenance 
period. The primary trigger of the contingency plan will be a violation 
of the ambient air quality standard for ozone. The trigger date will be 
the date that the State certifies to EPA that the data is quality 
assured, which will occur no later than 30 days after the recorded 
violation. The secondary trigger of the contingency plan will be an 
exceedance of the ozone standard that would indicate a violation could 
be imminent. This trigger will be activated within 30 days of the State 
finding the exceedance.
    Once either the primary or the secondary trigger is activated, the 
State Air Quality Section will commence analysis, including updated 
modeling as necessary, to determine what control measures will be 
required to bring the area back into attainment. By May 1 of the year 
following the ozone season in which the primary trigger has been 
activated, the State will complete the analysis and adopt stationary 
control measures indicated by the analysis, using the emergency rule 
process as necessary. The time frame for adopting measures other than 
for stationary sources will be based on the time frames in section 
181(b) of the CAA. Where only the secondary trigger has been activated, 
the State will complete the analysis and begin the regulatory adoption 
process for any measures that are needed by May 1 of the following 
year.

D. Contingency Plan

    The level of VOC and NOX emissions in the nonattainment area 
will largely determine its ability to stay in compliance with the 
O3 NAAQS in the future. Despite the State's best efforts to 
demonstrate continued compliance with the NAAQS, the ambient air 
pollutant concentrations may exceed or violate the NAAQS. Therefore, 
the State of North Carolina has provided contingency measures with a 
schedule for implementation in the event of a future O3 air 
quality problem. The actual measures will be determined from the 
analysis process described in 

[[Page 34866]]
the Verification of Continued Attainment portion of this document. The 
measures analyzed will include RACT or greater level control for 
NOX and VOC sources, particularly Duke Power and Transcontinental 
Gas Pipe Line Corporation, Stage II vapor control for gasoline 
dispensing facilities, RFG, enhancements to the I/M program, clean fuel 
fleet program, transportation control measures, and any other 
appropriate and feasible measures. EPA finds that the contingency plan 
provided in the State of North Carolina's submittal meets the 
requirements of section 175A(d) of the CAA.
E. Subsequent Maintenance Plan Revisions

    In accordance with section 175A(b) of the CAA, the State of North 
Carolina has agreed to submit a revised maintenance SIP eight years 
after the nonattainment area is redesignated to attainment. Such 
revised SIP will provide for maintenance for an additional ten years. 
Additionally, the State has indicated that should analysis of the 
current pre-adopted RACT contingency measures demonstrate that they 
will not be the most effective in bringing the area back into 
attainment, they may revise these pre-adopted measures in the future. 
Furthermore, based on updated analysis, the State has indicated they 
may periodically revise the contingency plan. All such revisions will 
be subject to full public participation in the regulatory adoption 
process.

Final Action

    EPA approves the State of North Carolina's request to redesignate 
to attainment the Charlotte-Gastonia O3 nonattainment area and 
maintenance plan. As discussed above, the emission statement, RACT 
catch-ups, and I/M requirements have been approved. EPA also approves 
the 1990 baseyear inventory for the Charlotte-Gastonia nonattainment 
area.
    EPA finds that there is good cause for this redesignation to become 
effective immediately upon publication because a delayed effective date 
is unnecessary due to the nature of a redesignation to attainment, 
which exempts the area from certain Clean Air Act requirements that 
would otherwise apply to it. The immediate effective date for this 
redesignation is authorized under both 5 U.S.C. section 553(d)(1), 
which provides that rulemaking actions may become effective less than 
30 days after publication if the rule ``grants or recognizes an 
exemption or relieves a restriction'' and section (d)(3), which allows 
an effective date less than 30 days after publication ``as otherwise 
provided by the agency for good cause found and published with the 
rule.''
    Under section 307(b)(1) of the Act, 42 U.S.C. 7607(b)(1), petitions 
for judicial review of this action must be filed in the United States 
Court of Appeals for the appropriate circuit by September 5, 1995. 
Filing a petition for reconsideration by the Administrator of this 
final rule does not affect the finality of this rule for purposes of 
judicial review nor does it extend the time within which a petition for 
judicial review may be filed, and shall not postpone the effectiveness 
of such rule or action. This action may not be challenged later in 
proceedings to enforce its requirements. (See section 307(b)(2) of the 
Act, 42 U.S.C. 7607(b)(2).)
    The OMB has exempted these actions from review under Executive 
Order 12866.
    Nothing in this action shall be construed as permitting or allowing 
or establishing a precedent for any future request for a revision to 
any state implementation plan. Each request for revision to the state 
implementation plan shall be considered separately in light of specific 
technical, economic, and environmental factors and in relation to 
relevant statutory and regulatory requirements.
    Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA 
must prepare a regulatory flexibility analysis assessing the impact of 
any proposed or final rule on small entities. 5 U.S.C. 603 and 604. 
Alternatively, EPA may certify that the rule will not have a 
significant impact on a substantial number of small entities. Small 
entities include small businesses, small not-for-profit enterprises, 
and government entities with jurisdiction over populations of less than 
50,000.
    Redesignation of an area to attainment under section 107(d)(3)(E) 
of the CAA does not impose any new requirements on small entities. 
Redesignation is an action that affects the status of a geographical 
area and does not impose any regulatory requirements on sources. The 
Administrator certifies that the approval of the redesignation request 
will not affect a substantial number of small entities.

Unfunded Mandates

    Under Sections 202, 203, and 205 of the Unfunded Mandates Reform 
Act of 1995 (``Unfunded Mandates Act''), signed into law on March 22, 
1995, EPA must undertake various actions in association with proposed 
or final rules that include a Federal mandate that may result in 
estimated costs of $100 million or more to the private sector, or to 
State, local, or tribal governments in the aggregate.
    Through submission of this state implementation plan or plan 
revision, the State and any affected local or tribal governments have 
elected to adopt the program provided for under section 175(A) and 
section 187(a)(1) of the Clean Air Act. These rules may bind State, 
local and tribal governments to perform certain actions and also 
require the private sector to perform certain duties. To the extent 
that the rules being approved by this action will impose no new 
requirements; such sources are already subject to these regulations 
under State law. Accordingly, no additional costs to State, local, or 
tribal governments, or to the private sector, result from this action. 
EPA has also determined that this final action does not include a 
mandate that may result in estimated costs of $100 million or more to 
State, local, or tribal governments in the aggregate or to the private 
sector.

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Hydrocarbons, Incorporation by reference, Intergovernmental relations, 
Nitrogen dioxide, Ozone, Reporting and recordkeeping requirements.

40 CFR Part 81

    Air pollution control, National parks, Wilderness areas.

    Dated: June 19, 1995.
Patrick M. Tobin,
Acting Regional Administrator.

    Chapter I, title 40, Code of Federal Regulations, is amended as 
follows:

PART 52--[AMENDED]

    1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401-7671q.

Subpart II--North Carolina

    2. Section 52.1770 is amended by adding paragraph (c)(83) to read 
as follows:


Sec. 52.1770  Identification of plan.

* * * * *
    (c) * * *
    (83) The maintenance plan and redesignation request for the 
Charlotte-Gastonia area which include Mecklenburg and Gaston Counties 
submitted by the State of North Carolina on November 12, 1993.
    (i) Incorporation by reference.
    (A) The following subsections of Section 3.0, entitled Maintenance 
Plan, 

[[Page 34867]]
in the Supplement To The Redesignation Demonstration and Maintenance 
Plan for the Charlotte/Gaston Ozone Nonattainment Area adopted by the 
North Carolina Environmental Management Commission on May 11, 1995: 3.1 
Concept of North Carolina's Maintenance Plan; 3.2 Foundation Control 
Program; Table 3.2 of Subsection 3.3; and 3.4 Contingency Plan.
    (ii) Other material. None.

PART 81--[AMENDED]

    1. The authority citation for part 81 continues to read as follows:

    Authority: 42.U.S.C. 7401-7671q.

    2. In Sec. 81.334, the ozone table is amended by removing the 
Charlotte-Gastonia area and its entries in the first alphabetical list 
and by adding in alphabetical order entries for ``Gaston County'' and 
``Mecklenburg County'' to the second listing of counties to read as 
follows:


Sec. 81.334  North Carolina.

* * * * *

                                              North Carolina--Ozone                                             
----------------------------------------------------------------------------------------------------------------
                                                         Designation                           Classification   
                                 -------------------------------------------------------------------------------
                                            Date\1\                        Type              Date\1\      Type  
----------------------------------------------------------------------------------------------------------------
Rest of State...................  ...........................  Unclassifiable/Attainment..  .........  .........
                                                                                                                
*                  *                  *                  *                  *                  *                
                                                        *                                                       
Gaston County...................  July 5, 1995...............                                                   
                                                                                                                
*                  *                  *                  *                  *                  *                
                                                        *                                                       
Mecklenburg County..............  July 5, 1995...............                                                   
                                                                                                                
*                  *                  *                  *                  *                  *                
                                                        *                                                       
----------------------------------------------------------------------------------------------------------------
\1\This date is November 15, 1990, unless otherwise noted.                                                      

* * * * *
[FR Doc. 95-16358 Filed 7-3-95; 8:45 am]
BILLING CODE 6560-50-P