Approval and Promulgation of Temporary Section 182(f) Exemption to the Nitrogen Oxides (NOINFX) Control Requirements for the Houston and Beaumont Ozone Nonattainment Areas; TX

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[TX-49-1-6678; FRL-5122-8]

Approval and Promulgation of Temporary Section 182(f) Exemption

to the Nitrogen Oxides (NOX) Control Requirements for the Houston

and Beaumont Ozone Nonattainment Areas; TX

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rulemaking.

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SUMMARY: The EPA proposes to approve a petition from the State of Texas

requesting that the Houston and Beaumont ozone nonattainment areas be

temporarily exempted from NOX control requirements of section

182(f) of the Clean Air Act (CAA) as amended in 1990. The State of

Texas bases its request upon preliminary photochemical grid modeling

which shows that reductions in NOX would be detrimental to

attaining the National Ambient Air Quality Standards (NAAQS) for ozone

in these areas. This temporary exemption is being requested under

section 182(f) of the CAA.

DATES: Comments on this proposed action must be received in writing on

or before February 13, 1995.

ADDRESSES: Written comments on this action should be addressed to Mr.

Guy Donaldson, Acting Chief, Planning Section, at the EPA Regional

Office listed below. Copies of the documents relevant to this proposed

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.

U.S. Environmental Protection Agency, Region 6, Air Programs Branch

(6T-A), 1445 Ross Avenue, suite 700, Dallas, Texas 75202-2733.

Texas Natural Resource Conservation Commission (TNRCC), P.O. Box 13087,

Austin, Texas 78711-3087.

FOR FURTHER INFORMATION CONTACT: Ms. Leila Yim Surratt or Mr. Quang

Nguyen, Planning Section (6T-AP), Air Programs Branch, EPA Region 6,

1445 Ross Avenue, Dallas, Texas 75202-2733, telephone (214) 665-7214.

SUPPLEMENTARY INFORMATION:

I. Background

NOX are precursors to ground level (tropospheric) ozone, or

urban ``smog.'' When released into the atmosphere, NOX will react

with volatile organic compounds (VOC) in the presence of sunlight to

form ozone. Tropospheric ozone is an important contributor to the

nation's urban air pollution problem.

The 1990 Clean Air Act Amendments (CAAA) made significant changes

to the air quality planning requirements for areas that do not meet the

ozone NAAQS. Subparts 1 and 2 of part D, title I of the CAA as amended

in 1990 contain the air quality planning requirements for ozone

nonattainment areas. Title I includes new requirements to control

NOX emissions in certain ozone nonattainment areas and ozone

transport regions. Section 182(f) requires States to apply the same

requirements to major stationary sources of NOX as are applied to

major stationary sources of VOC. The new NOX requirements are

reasonably available control technology (RACT) and new source review

(NSR). These provisions are explained more fully in the EPA's NOX

Supplement to the General Preamble published in the Federal Register

(FR) on November 25, 1992 (see 57 FR 55620). In addition, the general

and transportation conformity rules (conformity) required by section

176(c) contain new NOX control requirements (see 58 FR 63214 and

58 FR 62188), and the vehicle inspection and maintenance (I/M) rules

required by section 182(c)(3) also contain new NOX requirements

(see 57 FR 52989).

Houston, Texas was designated nonattainment for ozone and

classified as severe pursuant to sections 107(d)(4) and 181(a) of the

CAA, and has an attainment deadline of 2007. The Houston nonattainment

area includes the cities of Houston and Galveston, and consists of the

following eight counties: Brazoria, Chambers, Fort Bend, Galveston,

Harris, Liberty, Montgomery and Waller. Beaumont, Texas was classified

as a serious nonattainment area and has an attainment deadline of 1999.

The Beaumont nonattainment area includes the cities of Beaumont and

Port Arthur, and consists of the following three counties: Hardin,

Jefferson, and Orange. Please reference 56 FR 56694 (November 6, 1991,

codified for Texas at title 40 of the Code of Federal Regulations in

Sec. 81.344).

II. Applicable EPA Guidance

The CAA specifies in section 182(f) that if one of the conditions

listed below is met, the new NOX requirements would not apply:

1. In any area, the net air quality benefits are greater without

NOX reductions from the sources concerned;

2. In a nontransport region, additional NOX reductions would

not contribute to ozone attainment in the nonattainment area; or

3. In a transport region, additional NOX reductions would not

produce net ozone benefits in the transport region.

In addition, section 182(f)(2) states that the application of the

new NOX requirements may be limited to the extent that any portion

of those reductions are demonstrated to result in ``excess reductions''

of NOX. The NOX requirements of the conformity rules would

also not apply in an area that is granted a section 182(f) exemption

(see 58 FR 62188, 58 FR 63214, and 59 FR 31238). In addition, certain

NOX provisions of the I/M requirements would not apply in an area

that is granted a section 182(f) exemption (57 FR 52989).

The EPA's Guideline for Determining the Applicability of Nitrogen

Oxides Requirements under Section 182(f) (December 1993) describes how

the EPA intends to interpret the NOX exemption provisions of

section 182(f). In addition, a memorandum signed by John S. Seitz,

Director of the EPA Office of Air Quality Planning and Standards, dated

May 27, 1994, describes certain revisions to the process the EPA

currently intends to follow for granting exemptions from NOX

control requirements.

As described more fully in the Seitz memorandum, petitions

submitted under section 182(f)(3) are not required to be submitted as

State Implementation Plan (SIP) revisions. Consequently, the State is

not required under the CAA to hold a public hearing in order to

petition for an areawide NOX exemption determination. Similarly,

it is not necessary to have the Governor submit the petition.

III. State Submittal

On August 17, 1994, the TNRCC submitted to the EPA a petition

pursuant to section 182(f) which requests that the Houston and Beaumont

nonattainment areas be temporarily exempted by the EPA from the

NOX control requirements of section 182(f) of the CAA. The State

bases its petition on test (2) listed above, through the use of an

Urban Airshed Modeling (UAM) demonstration showing that NOX

reductions would not contribute to attainment in either area because

the decrease in ozone concentrations resulting from VOC reductions

alone is equal to or greater than the decrease obtained from NOX

reductions or a combination of VOC and NOX reductions.

The State's initial petition included: (1) A letter from John Hall,

Chairman of the TNRCC, to Jane N. Saginaw, Regional Administrator of

the EPA Region 6, transmitting the NOX exemption petition; and (2)

a summary of the State's UAM modeling results. The State of Texas

supplemented its initial submission on August 31, 1994, and September

9, 1994, by forwarding to the EPA four technical reports on the

modeling demonstration, which contained the following: base case model

inputs, base case performance evaluation, 1999 emissions report, and

1999 progress towards attainment modeling report. These additional

technical reports provided supplemental detail and documentation on the

modeling information already provided to the EPA in the State's initial

submission.

As described in the State's petition, the TNRCC plans to complete

additional UAM modeling between November 1995 and May 1996 using the

results of an intensive 1993 field study, the Coastal Oxidant

Assessment for Southeast Texas (COAST). The data collected through the

COAST study consist of hourly point source emissions, gridded typical

summer day on-road mobile source emissions, hourly air quality data,

and detailed meteorological data for specific ozone exceedance episodes

in the Houston-Beaumont domain. Because it is the most comprehensive

data set available, it should result in greater accuracy in the

modeling and therefore in the attainment control strategy. Since the

modeling is expected to be completed by May 1996, the TNRCC is

requesting only a temporary NOX exemption until May 31, 1997.

The TNRCC had previously adopted and submitted to the EPA complete

NOX RACT rules for the Houston and Beaumont areas. The NOX

RACT rules were adopted by the State on May 11, 1993, with additional

revisions adopted on August 30, 1993, May 25, 1994, and August 31,

1994. The TNRCC has also adopted and submitted to the EPA NOX NSR

and I/M rules. The State has recently adopted its conformity

regulations, and submitted them to the EPA in November 1994. The EPA

intends to act on these SIP revisions in separate rulemaking actions.

Once the results of the supplementary UAM modeling based on the

COAST data set are available, the State will re-evaluate whether

NOX reductions achieved through implementation of NOX RACT

will or will not contribute to attainment of the ozone standard in the

Houston and Beaumont areas. The EPA intends to defer action on the

State's NOX RACT rules until this re-evaluation is completed. If

the COAST modeling results continue to indicate that NOX RACT

reductions would not contribute or are detrimental to attainment of the

ozone standard in each of these areas, then the State would submit to

the EPA a section 182(f) petition requesting a permanent NOX

exemption, and would initiate rulemaking to rescind the NOX RACT

rules pending at EPA; however, if the modeling shows that NOX

reductions would contribute to attainment of the ozone standard in each

of these areas, the EPA would initiate rulemaking on the State's

NOX RACT rules which have been submitted to the EPA.

Because the State of Texas has decided, prompted by the initial

modeling results, to request that the EPA act at this time on the

NOX exemption petition rather than the previously submitted

NOX RACT rules, certain circumstances regarding the timing of

requirements under the CAA are necessarily affected. Section 182(b)(2)

of the CAA requires affected sources to implement the RACT measures

contained in applicable State rules by May 31, 1995. While Texas has

adopted NOX RACT rules, as noted previously, the EPA rulemaking to

approve those rules has been superseded by the NOX exemption

submission, proposing to temporarily exempt Texas from the requirement

to impose NOX RACT in the Houston and Beaumont nonattainment

areas. Based on the schedule for completion of the COAST study, from

which it will be determined whether NOX RACT reductions are needed

for these areas to attain, any action that will ultimately result in

sources being subject to NOX RACT rules will necessarily occur

only after the statutorily-prescribed deadline has passed. Since, as a

practical matter, it will be impossible for sources in these areas to

meet a deadline that has passed, the EPA believes it would have the

discretion in that event to establish a new, reasonable deadline by

which such sources must comply.

It is the EPA's determination, after consultation with the TNRCC,

that requiring subject sources to implement NOX control measures

as expeditiously as practicable but no later than May 31, 1997, is

appropriate for several reasons. First, through the State's NOX

RACT rule adoption process, affected sources have been made aware of

the requirement to implement NOX RACT, and in fact, the latest

revision to those rules specifically included the May 31, 1997,

compliance date. Moreover, the fact that the State has petitioned the

EPA for only a temporary NOX waiver has generally been made clear

to the public and affected sources. Finally, through this notice

setting forth how the EPA and the State of Texas intend to proceed with

regard to finalizing and applying the submitted NOX RACT rules in

the event a need for such reductions is established, sources have again

been made aware of the potential necessity (and the deadline that would

be applicable) to install and implement NOX RACT. Since the

information regarding whether NOX RACT will ultimately be required

is scheduled to become available by May 1996, sources will effectively

be provided with a year to implement the NOX RACT controls.

IV. Analysis of State Submittal

The following items are the basis for the EPA's action proposing to

approve the State of Texas' section 182(f) NOX petition for a

temporary NOX exemption for the Houston and Beaumont ozone

nonattainment areas. Please refer to the EPA's Technical Support

Document and the State's submittal for more detailed information.

Chapter 4 of the EPA's December 1993 section 182(f) guidance states

that photochemical grid modeling may be used to simulate conditions

resulting from three emission reduction scenarios: (1) substantial VOC

reductions; (2) substantial NOX reductions; and (3) both VOC and

NOX reductions. To demonstrate that NOX reductions are not

beneficial to attainment, the areawide predicted maximum 1-hour ozone

concentration for each day modeled under scenario (1) must be less than

or equal to that from scenarios (2) and (3) for the same day. Chapter 7

specifies that application of UAM should be consistent with the

techniques specified in the EPA ``Guideline on Air Quality Models

(Revised),'' and ``Guideline for Regulatory Application of the UAM,''

(July 1991). As discussed below, the State has met these conditions by

using the UAM consistent with the EPA's guidance.

A. Photochemical Grid Model

The TNRCC used UAM version IV, an EPA-approved photochemical grid

model, to develop the modeling demonstration for the Houston and

Beaumont areas. The State's modeling activities were performed as

outlined in the UAM modeling protocols, according to the EPA's

``Guideline for Regulatory Application of the Urban Airshed Model.'' A

specific modeling protocol was developed by the State for its modeling

activities. The State's modeling protocol was reviewed and approved by

the EPA. The discussion below summarizes the EPA's analysis on how the

State's modeling demonstrations complied with the EPA's guidance.

Please refer to the EPA's Technical Support Document for more detailed

information.

B. Episode Selection

The Houston and Beaumont areas are situated in the Upper Texas

Coastal Region which has a unique land-sea breeze regime in which

morning land breezes typically transition into afternoon sea breezes.

The EPA recommended method did not adequately address the source-

receptor relationships associated with the land-sea breeze regime in

the coastal area. Therefore, consistent with the intent of the EPA

guidance, Texas used a slightly modified approach to select episodes.

The TNRCC considered both morning and afternoon winds, and

meteorological regimes identified in a fashion similar to the EPA-

suggested procedure to account for the presence of the coastal land and

sea breezes. Data from 1987 through 1991 were examined for episodes

which cover at least 48 consecutive hours and the worst-case

meteorological conditions. Consistent with EPA guidance, three episodes

were selected for the UAM analysis.

C. Model Domain and Meteorological Input

The TNRCC selected a large modeling domain to ensure that the

movement of ozone and ozone precursors emitted from the surface sources

are well represented during the modeled episodes. In addition, since

Houston and Beaumont are adjacent to each other, the State combined

both areas into one modeling domain to avoid having overlapping wind

fields. This assisted the State in properly utilizing the prognostic

model, which requires the use of a large domain to capture all the

important horizontal and vertical circulation patterns. This domain

encompasses all emission sources and all surface meteorological/air

quality monitors in both areas.

Meteorological data was collected from numerous monitoring stations

in both areas. The TNRCC followed the methods described in the UAM

User's Guides to develop model inputs for wind field data, mixing

heights, temperature, and meteorological scalars for both areas. To

estimate the different boundary conditions and the initial conditions,

the TNRCC used several methods including monitored air quality data,

EPA-recommended background concentration levels, and Regional Oxidant

Model values.

D. Emissions Inventory

The Houston and Beaumont modeling exercises were conducted using

VOC and NOX emission inventories compiled by survey and direct

measurement by the TNRCC. The modeling emissions inventories are

composed of point source, area, on-road mobile, off-road mobile, and

biogenic emissions. The EPA procedures for developing episode-specific

emission inventories were followed.

The TNRCC developed the modeling inventories for the base case

model runs for all three episodes from the EPA-approved 1990 base year

SIP emission inventories for both areas. These inventories were used to

evaluate the model's performance for each episode.

For the section 182(f) demonstration, the EPA's guidance explains

that in general, the purpose of the section 182(f) requirements for

NOX is related to attainment of the ozone standard, which suggests

that an analysis is needed that is focussed on the time that attainment

of that standard is required. Therefore, the analysis should, at a

minimum, reflect conditions expected at the time the area is required

to attain the ozone standard.

The Beaumont area has an attainment deadline of 1999 and the

Houston area has an attainment deadline of 2007. Because the two areas

have different attainment deadlines, and because, for reasons explained

above, the TNRCC modeled both areas as one modeling domain, the State

conducted two section 182(f) analyses. First, the State modeled

generalized emissions inventory conditions that would be expected to

occur in the attainment year for Houston, by estimating 50 percent

reductions in VOC, in NOX, and in both, from the 1990 base year

emissions inventory.

Second, the State conducted a section 182(f) analysis using an

emissions inventory that reflects the conditions from 1996-1999. A

projected 1999 inventory was developed from the 1990 base year emission

inventory and adjusted to reflect conditions in 1999. Demographic and

econometric forecasting methods were employed to project activity

levels to the summer of 1999, which were in turn used to develop a

projected emissions inventory for 1999. The TNRCC then applied the VOC

emission reductions that will be achieved by implementation of controls

through 1996 from the 15 percent Reasonable Further Progress (RFP) SIP.

The TNRCC did not include any emission reductions that are required to

be implemented from 1996 through 1999 as part of the three percent per

year RFP requirements. In addition, the 1999 modeling inventory does

not incorporate any NOX emission reductions that would have been

achieved through implementation of NOX RACT, NSR, or

transportation conformity provisions.

The EPA believes that the two inventories used by the State for the

section 182(f) demonstration adequately simulate the conditions that

would be expected at the time the Beaumont area is required to attain

and at the time the Houston area is required to attain.

E. Model Performance

In the Houston and Beaumont model performance evaluation, both

graphical and statistical performance measures were implemented for all

meteorological episodes and monitoring networks. A sensitivity analysis

was also conducted. In the Houston and Beaumont base case simulations,

the model performed adequately for the May 16-19, 1988, and July 27-

August 1, 1990, episodes, but did not have satisfactory performance for

the October 10-15, 1991, episode which was therefore dropped from

further analysis.

The EPA's UAM guidance recommends that a minimum of three days from

among all meteorological regimes should be modeled (e.g., three

meteorological regimes each containing one primary episode day, or two

meteorological regimes with at least two primary days from one of those

regimes). The TNRCC's analyses are consistent with the EPA's guidance

in that the two episodes that exhibited satisfactory performance cover

more than three days of ozone exceedances and represent several of the

predominant meteorological regimes for ozone exceedances in the Gulf

Coast.

F. Section 182(f) Demonstration

Under the EPA's section 182(f) guidance, the State should model

three emission reduction scenarios to evaluate the benefits of NOX

reductions: (1) substantial VOC reductions; (2) substantial NOX

reductions; and (3) both VOC and NOX reductions.

The TNRCC first modeled the above across the board reduction

scenarios using the 1990 base year emissions inventory. The TNRCC

conducted three levels of emission reduction analyses: (1) 50 percent

VOC reductions, 50 percent NOX reductions, and 50 percent

reduction of both, (2) 35 percent VOC reduction, 20 percent NOX

reduction, and a mixed reduction of 25 percent VOC and 10 percent

NOX, and (3) 25 percent VOC reduction, 10 percent NOX

reduction, and a mixed reduction of 20 percent VOC and 5 percent

NOX.

As explained in the EPA's 182(f) guidance, the EPA believes it is

appropriate to focus this analysis on the areawide maximum 1-hour

predicted ozone concentration, since this value is critical to the

attainment demonstration. For the two episodes with adequate

performance, i.e., the May 1988 and July 1990 episodes, in all the

emission reduction scenarios conducted above, the controlling day shows

that the domain-wide predicted maximum ozone concentration is lowest

when only VOC reductions are modeled.

The TNRCC conducted a second analysis on the episode that exhibited

the best performance, i.e., the July 1990 episode. The TNRCC ran the

above across-the-board emission reduction scenarios with the July 1990

episode, using the projected 1999 inventory which incorporates VOC

control measures through 1996 (i.e., from the 15 percent RFP SIP). The

results of these scenarios show that for the controlling day, the

domain-wide predicted maximum ozone concentrations are lowest when only

VOC reductions are modeled. The State limited this second analysis to

the July 1990 episode because it exhibited significantly better

performance than the May 1988 episode. Furthermore, the maximum domain-

wide ozone concentration was larger in the July 1990 episode than in

May 1988. Thus, the level of controls necessary to reach attainment

with the July 1990 episode would likely be larger than for the May 1988

episode.

G. Evaluation Summary

The EPA believes that the TNRCC's modeling demonstration for the

Houston and Beaumont ozone nonattainment areas supports the State's

petition for a temporary exemption from the NOX requirements of

section 182(f) of the CAA. The State has followed the EPA's guidance on

the application of the UAM appropriately, and has demonstrated that

NOX reductions would not contribute to attainment.

Because the State's petition clearly indicates that the attainment

modeling should be completed between November 1995 and May 1996 (which

will determine whether a VOC, NOX, or combination thereof,

strategy is most beneficial for attainment), the EPA believes that the

petition supports granting the State's request for a temporary

exemption only until the end of 1996. The EPA believes that allowing

the temporary exemption only until this time is needed to provide

adequate insurance that if the subsequent COAST attainment modeling

indicates that NOX reductions would be effective in reducing

ozone, the NOX control requirements of section 182(f) would be

implemented without undue delay.

Through the granting of a temporary NOX exemption, in addition

to NOX RACT, the NOX NSR, conformity, and certain portions of

the I/M requirements of the CAA would no longer be applicable for the

Houston and Beaumont areas. If the State does not receive a permanent

exemption, then the NOX RACT, NSR, conformity, and I/M

requirements of the CAA would become applicable again upon the

expiration of the temporary exemption. As explained previously for

RACT, if the NOX requirements re-apply, then the EPA must

establish new compliance deadlines for those requirements.

If the State has not received a permanent exemption prior to the

expiration of the temporary exemption, based on the compliance deadline

in the previously submitted NOX RACT rules, the EPA would expect

affected sources in the State to implement NOX RACT controls as

expeditiously as practicable but no later than May 31, 1997. Finally,

the TNRCC's petition states that the COAST attainment modeling will be

completed between November 1995 and May 1996. Therefore, by May 1996,

the State will be able to determine whether NOX reductions will

contribute to attainment and thus whether the NOX RACT rules will

need to be implemented in the Houston and Beaumont areas. The EPA

therefore believes that affected sources will have adequate prior

notice to meet the NOX RACT compliance deadline indicated above in

the event that a permanent exemption is not granted. The NOX NSR,

conformity, and I/M provisions would become applicable immediately upon

the expiration of the temporary exemption.

V. Proposed Rulemaking Action

In this action, the EPA proposes to approve the section 182(f)

petition submitted by the State of Texas requesting a temporary

NOX exemption for the Houston and Beaumont ozone nonattainment

areas. The temporary exemption, if granted, would expire on December

31, 1996, without further notice from the EPA.

The State had previously adopted and submitted to the EPA complete

NOX RACT and NSR rules, and recently submitted conformity rules to

the EPA. During the temporary exemption period, the EPA will not act

upon the State's NOX RACT rules. The EPA plans to act upon the

State's NOX NSR and conformity provisions in separate rulemaking

actions because those provisions are contained in broader rules that

also control VOC emissions.

Upon the expiration of the temporary exemption on December 31,

1996, the State is required to either, (1) have received a permanent

NOX exemption from the EPA prior to that time, or (2) begin

implementing the State's NOX RACT, NSR, conformity and I/M

requirements, with NOX RACT compliance required as expeditiously

as practicable but no later than May 31, 1997. The EPA will begin

rulemaking action on the State's NOX RACT SIP upon the expiration

of the temporary exemption if the State has not received a permanent

NOX exemption by that time.

Request for Public Comments

The EPA requests comments on all aspects of this proposal. The EPA

has received an advance request from an environmental group to extend

the comment period from the normal 30-day period to a 60-day period

because of the complex technical issues involved in the petition. The

EPA is granting the group's request for a 60-day comment period.

Therefore, as indicated at the outset of this action, the EPA will

consider any comments received by February 13, 1995.

Regulatory Process

Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., the 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, the EPA may certify that the rule will not have a

significant economic 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.

Approvals of NOX exemption petitions under section 182(f) of

the CAA do not create any new requirements. Therefore, because the

Federal approval of the petition does not impose any new requirements,

the EPA certifies that it does not have a significant impact on

affected small entities. Moreover, due to the nature of the Federal-

State relationship under the CAA, preparation of a regulatory

flexibility analysis would constitute Federal inquiry into the economic

reasonableness of State action. The CAA forbids the EPA to base its

actions concerning SIPs on such grounds (Union Electric Co. v. U.S.

E.P.A., 427 U.S. 246, 256-66 (S. Ct. 1976); 42 U.S.C. 7410 (a)(2)).

Executive Order 12866

Under Executive Order 12866, (58 FR 51735 (October 4, 1993)), the

EPA must determine whether the regulatory action is ``significant'',

and therefore subject to Office of Management and Budget (OMB) review

and the requirements of the Executive Order. It has been determined

that this rule is not a ``significant regulatory action'' under the

terms of Executive Order 12866, and is therefore not subject to OMB

review.

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, Hydrocarbons,

Intergovernmental relations, Nitrogen dioxide, Ozone, Volatile organic

compounds.

Dated: December 9, 1994.

Carol M. Browner,

Administrator.

40 CFR part 52 is proposed to be amended as follows:

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

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

Subpart SS--Texas

2. Section 52.2308 is proposed to be amended by reserving paragraph

(c) and adding paragraph (d) to read as follows:

Sec. 52.2308 Area-wide nitrogen oxides (NOX) exemptions.

* * * * *

(c) [Reserved]

(d) The TNRCC submitted to the EPA on August 17, 1994, with

supplemental information submitted on August 31, 1994, and September 9,

1994, a petition requesting that the Houston and Beaumont ozone

nonattainment areas be temporarily exempted from the NOX control

requirements of section 182(f) of the CAA. The Houston nonattainment

area consists of Brazoria, Chambers, Fort Bend, Galveston, Harris,

Liberty, Montgomery, and Waller counties. The Beaumont nonattainment

area consists of Hardin, Jefferson, and Orange counties. The exemption

request was based on photochemical grid modeling which shows that

reductions in NOX would be detrimental to attaining the ozone

NAAQS. On (insert date), the EPA approved the State's request for a

temporary exemption. The temporary exemption automatically expires on

December 31 1996, without further notice from the EPA. Upon the

expiration of the temporary exemption, the State is required to either,

(1) have received a permanent NOX exemption from the EPA prior to

that time, or (2) begin implementing the State's NOX requirements,

with NOX Reasonably Available Control Technology compliance

required as expeditiously as practicable but no later than May 31,

1997.

[FR Doc. 94-30872 Filed 12-14-94; 8:45 am]

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