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57160 Federal Register/Vol. 66, No. 220/Wednesday, November 14, 2001/Rules and Regulations

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 52

[TX-126-1-7477; FRL-7092-2]

Approval and Promulgation of

Implementation Plans; Texas;

Houston/Galveston Nonattainment

Area; Ozone

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Final rule.

SUMMARY: The EPA is fully approving

the Texas one-hour ozone attainment

demonstration State Implementation

Plan (SIP) for the Houston/Galveston

(HG) severe nonattainment area with an

attainment date of November 15, 2007.

Also, being published in today's Federal

Register are seven additional actions,

approving various measures that

support the attainment demonstration.

In this action, the EPA is approving

the following related SIP elements: The

following local measures relied on in

the attainment demonstration: speed

limit reduction, voluntary mobile

emission programs (VMEP) and

transportation control measures (TCM);

the Post 1999 Rate of Progress (ROP)

plans for the time periods November 15,

1999 to November 15, 2002, November

15, 2002 to November 15, 2005 and

November 15, 2005 to November 15,

2007; the Motor Vehicle Emissions

Budget (MVEB) contained in the

attainment demonstration SIP and the

Post 1999 ROP plans; the 15% ROP Plan

(Conversion of conditional interim

approval to a full approval); certain

enforceable commitments to adopt

additional measures and perform

additional analyses; revisions to the

1990 base year inventory; and the HG

area's SIP as meeting the reasonably

available control measures (RACM)

requirement.

DATES: This final rule is effective on

December 14, 2001.

ADDRESSES: Copies of documents

relevant to this action are available for

public inspection during normal

business hours at the Environmental

Protection Agency, Region 6, Air

Planning Section (6PD-L), 1445 Ross

Avenue, Dallas, Texas 75202-2733; and,

the Texas Natural Resource

Conservation Commission, Office of Air

Quality, 12124 Park 35 Circle, Austin,

Texas 78753.

FOR FURTHER INFORMATION CONTACT: Guy

R. Donaldson, Air Planning Section

(6PD-L), 1445 Ross Avenue, Dallas,

Texas 75202-2733. Telephone Number

(214) 665-7242, E-mail Address:

Donaldson.Guy@epa.gov.

SUPPLEMENTARY INFORMATION:

Throughout this document "we," "us,"

and "our" means EPA.

Table of Contents

I. Final Action

A. What Elements of the Texas SIP Are We

Approving?

B. What are the Motor Vehicle Emissions

Budgets being Approved in this Action?

C. What Are the Key SIP Submissions

Being Approved in this Action?

D. What Previous Action has EPA Taken?

E. What Changes Have Been Made in

Response to Comment on the EPA and

TNRCC Parallel Proposals?

II. What SIP Elements Did We Need to Take

Final Action on Before We Could

Approve the Attainment Demonstration?

III. Comments

A. What Comments Were Received?

i. What comments Were Received on the

December 1999 Proposed Approval/

Proposed Disapproval?

ii. What Comments Were Received on the

July 28, 2000 Supplemental Proposal

Concerning MVEBs?

iii. What Comments Were Received on the

July 12, 2001 Proposed Approval?

B. Response to Comments on Attainment

Demonstration

1. General Comments

2. Comments on Photochemical Modeling a. Model Performance

b. Model Inputs c. Weight of Evidence Analysis

3. Comments on Control Strategies

4. Comments on Enforceable Commitments

5. Comments on Motor Vehicle Emissions

Budgets

a. Comments on July 12, 2001 Proposal

b. Comments on July 28, 2000

Supplemental Notice Proposal

6. Comments on RACM a. Comments on December 16, 1999

Proposal

b. Comments on July 12, 2001 Proposal

C. Response to Comments on Local

Measures

1. Comments on Speed Limits

2. Comments on VIEP

3. Comments on TCMs

D. Response to Comments on Post 1999

Rate of Progress Plans

E. Response to Comments on

Administrative Record

IV. Administrative Requirements

I. Final Action

A. What Elements of the Texas SIP Are

We Approving?

We are fully approving the one-hour

ozone attainment demonstration SIP for

the HG nonattainment area as meeting

the attainment demonstration

requirements of 182(c)(2) and (d) of the

Clean Air Act (the Act). We proposed

this action on July 12, 2001 (66 FR

36655). This demonstration shows,

through photochemical modeling and

other evidence, that through a

combination of adopted measures,

recent legislation, and commitments to

adopt additional measures the HG area

will attain the one-hour ozone standard

by November 15, 2007.

As an integral part of the attainment

demonstration, we are approving and

finding adequate the associated MVEBs

only until these emission budgets have

been revised pursuant to the State's

enforceable commitments to use

MOBILE6 and to adopt additional

measures necessary for attainment and

we have found the revised budgets

adequate for the purposes of

transportation conformity.

Before approving an attainment

demonstration SIP, we must approve all

of the control measures relied on in the

demonstration. The majority of the

control measures relied on in the

attainment demonstration have been

approved in other Federal Register

notices. (See Section II for a listing of

related Federal Register notices.) We are

approving in today's action, certain

measures relied upon in the attainment

demonstration and which were

submitted December 20, 2000: the

Speed Limit Reductions, the VMEP, and

the TCMs. We are also approving the

following related SIP elements:

* 15% ROP Plan,

* The Post 1999 ROP Plans and their

associated contingency measures;

* A demonstration that all RACM

have been adopted for the HG

nonattainment area; and

* Revisions to the 1990 Base Year

Inventory.

The revisions to the Post 1999 ROP

plans and the RACM analysis that we

are approving today were parallel

processed. (See Section I.E. for a

discussion of parallel processing.)

In addition, we believe that for the HG

area to be successful in attaining the

one-hour ozone standard, the State must

be committed to certain future actions

relating to adopting additional measures

and to future evaluations of the inputs

to the plan. To that end, Texas has

included the following enforceable

commitments in their State

Implementation Plan which we are

approving:

* The State's enforceable

commitment to perform a mid-course

review (including evaluation of all

modeling, inventory data, and other

tools and assumptions used to develop

this attainment demonstration) and to

submit a mid-course review SIP

revision, with any recommended midcourse corrective actions, to the EPA by

May 1, 2004.

* The State's enforceable

commitment to perform new mobile

source modeling for the HG area, using

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MOBILE6, our on-road mobile

emissions factor computer model,

within 24 months of the model's official

release; that if a transportation

conformity analysis is to be performed

between 12 months and 24 months after

the MOBILE6 official release,

transportation conformity will not be

determined until Texas submits an

MVEB which is developed using

MOBILE6 and which we find adequate.

* An enforceable commitment to

adopt rules that achieve at least the

additional 56 tons/day of NOx emission

reductions that are needed for the area

to show attainment of the one-hour

ozone standard and as supported by

identified measures that could

potentially be adopted and could

achieve the reductions without

requiring additional limits on highway

construction.

* An enforceable commitment to

adopt and submit the EPA by December

1, 2002 measures to achieve 25% of the

56 tons/day.

* An enforceable commitment to

adopt and submit to EPA by May 1,

2004 measures for the remaining needed

additional NOx reductions.

* An enforceable commitment that

the rules needed for the additional NOx

reductions will be adopted as

expeditiously as practicable and the

compliance dates will be expeditious.

* An enforceable commitment to

concurrently revise the MVEBs and

submit them to EPA as a revision to the

attainment SIP if additional control

measures reduce the motor vehicle

emissions budget (MVEB).

This action also satisfies the last two

elements of section 182(d)(1)(A) of the

Act to adopt TCMs as necessary to

comply with the reasonable further

progress and attainment demonstration

requirements of the Act. The first

requirement to offset growth in

emissions from growth in vehicle miles

traveled (VMT) or number of vehicle

trips is addressed in a corresponding

action published separately in today's

Federal Register. Please see Section

III.C.3 for additional discussion

regarding the second and third

elements. For additional discussion

regarding the first element, see the

corresponding separate action in today's

Federal Register regarding the VMT

Offset Plan.

For more discussion on the rationale

for the actions being approved here, see

the proposed approvals with their

associated Technical Support

Documents (TSD) and our response to

comments found in Section II.

B. What Are the Motor Vehicle

Emissions Budgets Being Approved in

This Action?

Rate of Progress Budgets

The MVEBs established by the Post

1999 Rate of Progress plans and that we

are approving today are contained in

Table 1. We find the MVEBs consistent

with all ROP SIP requirements. In

addition, we are finding these budgets

adequate for transportation conformity

purposes pursuant to the criteria in 40

CFR 93.118(e)(4) as part of our action on

the SIP rather than using the web

posting process because we have moved

forward on this SIP in a quick manner

as described in Guidance on Motor

Vehicle Emissions Budgets in One-Hour

Ozone Attainment Demonstrations

dated November 3, 1999.

TABLE 1 .- ROP SIP MOTOR VEHICLE

EMISSIONS BUDGETS

[Tons per day]

Pollutant 2002 2005 2007

VOC ................ 100.07 68.52 79.51

NOx ................ 260.85 185.48 156.6

The new 2007 budgets are taken from

the attainment demonstration modeling

rather than directly from the ROP

calculations. Emissions estimates used

to demonstrate transportation

conformity will be derived using the

assumptions used to develop these

emissions budgets for the 2007

attainment SIP MVEBs, pursuant to 40

CFR 93.122(a)(6). We find such MVEBs

consistent with ROP.

Attainment Budgets

Table 2 contains the MVEBs

established by the attainment plan. We

are approving these budgets today and

finding them adequate for transportation

conformity purposes pursuant to the

criteria in 40 CFR 93.118(e)(4) as limited

below.

TABLE 2.-2007 ATTAINMENT YEAR

MOTOR VEHICLE EMISSIONS BUDGETS

[Tons per day]

Pollutant 2007

V O C .............................................. 7 9 .5 1

N O x .............................................. 15 6 .6 0

We find the MVEBs consistent with

all pertinent SIP requirements and, as

described in our proposals, the MVEBs

are approved and adequate for

conformity purposes only until these

emission budgets have been revised

pursuant to the State's enforceable

commitments to use MOBILE6 and to

adopt additional measures necessary for

attainment and we have found the

revised budgets adequate for the

purposes of transportation conformity.

All States whose attainment

demonstration includes the effects of

EPA's Tier II/Low Sulfur program have

committed to revise and resubmit their

budgets after EPA releases

MOBILE6.(MOBILE6 is the latest

version of the EPA model for estimating

mobile emissions. Its official release is

expected in the near future.) The State

committed in its April 2000 submission

to perform new mobile source modeling

for the HG area using MOBILE6 within

24 months of the model's official

release. If transportation conformity

analysis is to be performed between 12

and 24 months of the official release of

MOBILE6, transportation conformity

will not be determined until the State

submits a new budget which is

developed using MOBILE6 and which

we find adequate. The State has

informed the transportation agencies of

this commitment. Texas also commits to

concurrently revise the MVEB if

adoption of any shortfall measure affects

the MVEB and submit the revision to

EPA as a revision to the attainment SIP.

We are limiting the duration of our

approval as described above because we

are only approving the attainment

demonstrations and MVEBs because the

States have committed to revise them.

Therefore, once we have confirmed that

revised budgets are adequate, they will

be more appropriate than the budgets

we are approving today.

C. What Are the Key SIP Submissions

Being Approved in This Action?

There have been a number of State

submissions in response to the

attainment demonstration requirements

of the Act. In this notice, the key State

submissions being considered were

provided by the Governor in letters

dated December 20, 2000, and October

4, 2001. The items in the October 4,

2001 submission have been parallel

processed. Parallel processing means

that EPA proposes action on a state rule

before it becomes final under state law.

Our July 12, 2001 proposal details the

history of State and EPA actions that

preceded these submissions (66 FR

36655).

D. What Previous Actions Has EPA

Taken?

There are three proposals related to

this action. First, on December 16, 1999

(64 FR 70548), we issued a proposed

approval/proposed disapproval of the

HG ozone attainment demonstration

plan (the 1998 plan). This action

outlined the actions we believed were

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necessary for the State to develop a fully

approvable plan. Second, on July 28,

2000 (65 FR 46383), we issued a notice

of proposed rulemaking regarding how

the adequacy of attainment MVEBs

would be handled for the one-hour

ozone nonattainment areas. Finally, on

July 12, 2001 (66 FR 36655), we

proposed approval of the HG ozone

attainment demonstration plan (the

December 2000 plan as proposed to be

revised by the State and finally adopted

and submitted in a letter dated October

4, 2001) and several related actions. In

today's notice, we have addressed all of

the comments received on the three

proposals.

E. What Changes Have Been Made in

Response to Comment on EPA and

TNRCC Parallel Proposals?

In a letter dated June 15, 2001, the

Governor of Texas submitted several

items for parallel processing. These

items were: certain commitments; recent

legislative changes with their impacts

on and revisions to the proposed control

strategy for the HG area; the corrections

and modifications to the Post 1999 ROP

plans; a demonstration that all RACM

have been adopted for the HG

nonattainment area; and a modification

to the attainment demonstration and

MVEB to revise the emission projection

for Heavy Duty Diesel vehicles.

Under parallel processing, EPA takes

final action on its proposal if the final,

adopted state submission is

substantially unchanged from the

submission on which the proposed

rulemaking was based, or if significant

changes in the final submission are

anticipated and adequately described in

EPA's proposed rulemaking or result

from needed corrections determined by

the State to be necessary through review

of issues described in EPA's proposed

rulemaking. Several minor changes were

made by the State in response to

comment.

Enforceable Commitments

Texas made the following changes to

the language of their enforceable

commitments. Italicized text has been

added.

The commission commits to adopt

measures necessary to achieve at least

56 tpd of NOx emission reductions in

the HGA area above and beyond those

reductions already identified by the

control measures listed in Chapter 6,

Table 6.1-2.

To demonstrate progress towards the

56 tpd that commitment, the

commission intends to evaluate the

following measures and to adopt, by

November 2002, sufficient measures in

order to achieve at least 25% of the

estimated 56 tpd needed.

TNRCC also in response to comments

now lists all of the enforceable

commitments for the HG area in a single

location in Chapter 7.

We agree that these changes are not

significant in that they clarify the intent

of the enforceable commitments and

therefore, remain approvable. No further

notice is necessary since these changes

do not substantively change the State's

proposal.

Changes to the Rate of Progress Plan

TNRCC also revised the tables in the

Post 1999 Rate of Progress Plans in

response to EPA comments that the

Tables did not reflect the revised

implementation schedules for the point

source NOx rules. This issue was

discussed in our proposed approval

which was based on conservative

estimates of the emission reductions.

The revised tables in the October 4,

2001 SIP reflect the new

implementation schedule. No further

notice is required since the State made

changes as discussed by EPA in the

proposal notice. The following summary

table is based on the revised estimates.

TABLE 1 .- NOx RATE OF PROGRESS

M ile sto ne Y e a r ............................... 2 0 0 2 .............................................. 2 0 0 5 .............................................. 2 0 0 7 .

T a rget Leve l ................................... 112 7.08 ......................................... 10 11.33 ....................... ........ 935 .6 7.

Projected emissions after controls 1115.76 ......................................... 630.05 ........................................... 444.04.

Measures ....................................... Tier I NLEV RFG I/M Small En- Tier 1/11 I/M HDDV Standards ....... Tier 1/11 HDDV Standards

gine HDDV Standards. NOx Point Source controls ........... NOx Point Source controls.

II. What SIP Elements Did We Need To

Take Final Action on Before We Could

Approve the Attainment

Demonstration?

In our proposed action on July 13,

2001, we explained that we could not

finalize approval of the attainment

demonstration for the HG area until we

finalize approval of several related

actions. These actions are listed below

along with the status of their final

approval.

1. Vehicle I/M program (30 TAC 114).

Final approval published separately in

this issue of the Federal Register.

2. Revised emission specifications in

the HG area for NOx Point Sources (30

TAC 117). Final approval published

separately in this issue of the Federal

Register.

3. NOx Cap and Trade program (30

TAC 101). Final approval published

separately in this issue of the Federal

Register.

4. Low emission diesel fuel (30 TAC

114). Final approval published

separately in this issue of the Federal

Register.

5. Non-Road Large Spark-Ignition

(LSI) Engines (30 TAC Chapter 114).

Final approval published separately in

this issue of the Federal Register.

6. Agreed Orders with Continental

and Southwest Airlines and the City of

Houston. Final approval published

separately in this issue of the Federal

Register.

7. Reasonably Available Control

Technology (RACT) rules regulating

VOCs from Batch Processes (30 TAC

115) and Offset Lithographers (30 TAC

115). Direct final action was published

July 16, 2001 (66 FR 36913). No

comments were received and this action

became effective September 14, 2001.

8. A determination that the HG SIP

includes all Reasonably Available

Control Measures. Final approval in this

action.

9. The 15% ROP Plan. Final approval

in this action.

10. The Post 1999 ROP Plans and

contingency measures. Final approval in

this action.

11. The revisions to the 1990 base

year inventory. Final approval in this

action.

12. The speed limit reductions, the

VMEP and the TCMs. Final approval in

this action.

13. Lawn service equipment operating

restrictions (30 TAG 114.452-459). Final

approval published separately in this

issue of the Federal Register.

14. Vehicle Miles Traveled (VMT)

Offset Plan submitted August 25, 1997

and with minor, non-substantive

revisions submitted on May 17, 2001.

Final approval published separately in

this issue of the Federal Register for the

first element of 182(d)(1)(A). The last

two elements of 182(d)(1)(A) are

satisfied by this action.

15. Motor Vehicle Idling Limitations

(30 TAG 114.500-509). Final approval

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published separately in this issue of the

Federal Register.

16. Stationary Diesel Generator rule

(30 TAC 117.206). Final approval

published separately in this issue of the

Federal Register.

17. The Post 1996 ROP Plan and

contingency measures. Direct final

action was published April 25, 2000, 66

FR 20746. No comments were received

and this rule became effective June 26,

2000.

III. Comments

A. What Comments Were Received?

i. What Comments Were Received on

the December 1999 Proposed Approval/

Proposed Disapproval?

The following comment letters were

received on the December 1999

proposal:

(1) February 14, 2000 letter from

Robert E. Yuhnke, Attorney for

Environmental Defense.

(2) February 14, 2000 letter from

Jeffrey Saitas, Executive Director

TNRCC.

(3) July 31, 2000 letter from James 0.

Bartholomew, ELM Packaging.

ii. What Comments Were Received on

the July 28, 2000 Supplemental

Proposal Concerning MVEBs?

The following comment letter was

received on this supplemental proposal.

(1) August 28, 2000 letter from

Environmental Defense.

iii. What Comments Were Received on

the July 12, 2001 Proposal?

We received the following 13

comment letters on the July 12, 2001

proposal.

(1) Letter from D. Marrach, M.D. dated

July 2, 2001.

(2) August 10, 2001 letter from Patrick

Gallagher, Sierra Club.

(3) August 13, 2001 letter from John

Wilson and Frank Blake, the GalvestonHouston Association of Smog

Prevention (GHASP).

(4)August 13, 2001 letter from B.C.

Carmine, Reliant Energy.

(5)August 13, 2001 letter from Ramon

Alvarez, PhD, Environmental Defense.

(6) August 8, 2001 letter from Jack

Steele, Houston Galveston Area Council.

(7) August 13, 2001 letter from Nelly

Rocha, Baker and Botts for the Business

Coalition for Clean Air Appeal Group.

(8) August 10, 2001 letter from Albert

Axe, Jr., Jenkens & Gilcrest for TXI

Operations.

(9) August 13, 2001 letter from John

R. Evans, Lyondell.

(10) August 13, 2001 letter from T.

Hefgott, Enterprise Products.

(11) August 3, 2001 letter from

Howard Runser, private citizen.

(12) August 8, 2001 letter from Brant

Mannchen, Houston Regional Group of

the Sierra Club.

(13) August 13, 2001 letter from John

D. Walke, Senior Attorney, NRDC.

No comments were received on the

proposed approval of the 15% ROP plan

or the proposed approval of revisions to

the 1990 Base Year Inventory. These

actions are being approved with out

further discussion.

B. Response to Comments on

Attainment Demonstration

1. General Comments

Comment: Several commenters urged

EPA to disapprove the attainment plan

because they believe the plan does not

include complete modeling, enforceable

versions of all Reasonably Available

Control Measures (RACM) and a control

strategy sufficient to achieve attainment.

One commenter went on to say because

they believe the plan should be

disapproved and, under the consent

decree in NRDC v. Browner, Civ. No.

99-2976, EPA must commence

promulgation of a Federal

Implementation Plan (FIP). One

commenter supported the proposed

approval.

Response: In the following responses,

we address the specific concerns raised

by the commenters in more detail. We

believe the plan provided by the State

of Texas is fully approvable under the

Act and will provide for attainment as

expeditiously as practicable which is by

November 15, 2007 and the plan

includes all reasonably available control

measures. Therefore, we are finalizing

our approval in this action.

Furthermore, because we are fully

approving the plan as meeting the

requirements of 182(c)(2) and (d) of the

Act, it is unnecessary to commence

development of a FIP.

Comment: TNRCC has not provided

modeling that shows attainment in

2007. (Really 2005 since 4 exceedences

in that year ensures failure to meet the

three-year standard.) A commenter also

states that there is no demonstration of

maintenance of the ozone standard

below the 0.12 ppm one-hour standard

beyond 2007.

Response: EPA has taken the position

that for nonattainment areas subject to

the requirements of subpart 2 of part D

of the Act, that the area needs to

demonstrate that in the attainment year,

the area will have air quality such that

the area could be eligible for the two

one-year extensions provided under

section 181(a)(5) of the Act. Under

section 181(a)(5), an area that does not

have three-years of data demonstrating

attainment of the ozone NAAQS, but

has complied with all of the statutory

requirements and that has no more than

one exceedance of the NAAQS in the

attainment year, may receive a one-year

extension of its attainment date.

Assuming those conditions are met the

following year, the area may receive an

additional one-year extension. If the

area has no more than one exceedance

in this final extension year, then it will

have three-years of data indicating that

it has attained the ozone NAAQS.

This position is consistent both with

EPA's modeling guidance and with the

structure of subpart 2 of the Act. Under

EPA's modeling guidance, states model

air quality for the attainment year-they

do not model air quality for the threeyear period preceding the attainment

year. This is largely a function of how

the model operates that the data

produced only predicts the air quality

for one year. EPA's modeling guidance

has existed for many years and has been

relied on by numerous areas for

demonstrating attainment of the ozone

standard.

Moreover, EPA believes this approach

is consistent with the statutory structure

of subpart 2. Under subpart 2, many of

the planning obligations for areas were

not required to be implemented until

the attainment year. Thus, Congress did

not assume that all measures needed to

attain the standard would be

implemented three years prior to the

area's attainment date. For example,

areas classified as marginal-which had

an attainment date of three years

following enactment of the 1990 Clean

Air Act amendments were required to

adopt and implement RACT and I/M

"fix-ups" that clearly could not be

implemented three years prior to their

attainment date. Similarly, moderate

areas were required to implement RACT

by May 1995, only 18 months prior to

their attainment date of November 1996.

Also, the ROP requirement for moderate

and above areas, including the 15%

plan for reductions by November 1996,

applies through the attainment year.

Thus, EPA believes that Congress did

not intend that these additional

mandatory reductions be in excess of

what is needed to achieve three-years of

"clean data." For these reasons, EPA

does not agree with the commenter that

the State's attainment demonstration

needs to demonstrate that the area will

have three years of data showing

attainment in the attainment year.

However, EPA does believe that the Act

requires and that it is prudent for States

to implement control as expeditiously

as practicable. EPA also believes that for

the HG area, all measures are being

implemented as expeditiously as

practicable and that the area has

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demonstrated attainment consistent

with EPA's modeling guidance.

A plan for maintenance of the

Standard is not necessary for the

attainment demonstration to be

approved. A State is not required by the

Act to provide a maintenance plan until

the State petitions for an area to be

redesignated to attainment which will

not occur until the HG area has three

years of data showing compliance with

the Standard.

While it is not necessary for the State

to provide for maintenance of the

standard at this time, we do believe

emissions in the HG area will continue

to decrease after 2007 due to on and off

road vehicle emission control programs

that will continue to provide additional

reductions as the fleet continues to

turnover after 2007. So there is reason

to believe that air quality will continue

to improve after the attainment date.

Comment: Two commenters suggested

the plan should address other air

pollution concerns in addition to

attainment of the one-hour standard.

One commenter suggested the plan

should provide as much progress as

possible toward implementing the 8-

hour standard as the requirements of the

Act and EPA's implementing

regulations allow. Another commenter

said that ozone reduction should be

used as a spur in reducing toxic

emissions and particulate matter as

well.

Response: As an initial matter, these

comments are outside the scope of this

rulemaking. EPA's review here is

focused on whether the submitted plan

meets the statutory requirements for

attainment of the one-hour ozone

standard. Nevertheless, EPA believes

the reductions in ozone precursors in

this plan will provide reductions both

toward attainment of the one-hour

standard and substantial progress

toward the 8-hour standard.

Furthermore, NOx emissions are a

precursor to particulate matter

formation. So the large NOx emissions

reductions in the plan should provide

improvements in particulate matter

levels. In addition, while the focus of

the plan is on reducing NOx emissions,

VOC emissions will also be reduced by

approximately 40% from 1993 levels.

Some of these VOCs are also air toxics.

Again, while EPA believes these

additional air quality benefits will result

from the implementation of this plan,

the approval of the plan depends, as a

legal matter, only on whether the plan

will result in attainment of the one-hour

ozone standard.

2. Comments on the Photochemical

Modeling

a. Model Performance

Comment: The photochemical

modeling is fundamentally flawed and

should not be used as proposed. The

ozone plots prepared by TNRCC as part

of its graphical performance analysis

show significant subregional biases in

the model with systematic under

predictions and over predictions. The

commenter states that the graphical

analysis provides far more insight into

the performance of the model than any

other type of performance measure. The

statistical measures distort the

appearance of model performance by

averaging out the subregional biases.

Response: EPA does not agree that the

graphical analysis provides more insight

into model performance than any other

performance measures. EPA believes all

model performance measures should be

considered. There is no rigid criterion

for model acceptance or rejection in

assessing model simulation results for

the performance evaluation. As

recommended by EPA, the State's model

performance evaluations for the selected

episode included diagnostic and

sensitivity analyses, and graphical and

statistical performance measures.

TNRCC used these performance

measures in conjunction with one

another to evaluate the performance of

the model. Diagnostic and sensitivity

analyses consisted of testing the

response of modeled ozone to changes

in the various model inputs (i.e.,

meteorology, emission inventory, and

initial & boundary conditions). The

model performance evaluation was

based upon graphical measures

consisting of comparing time series of

monitored and modeled ozone and

ozone precursor concentrations, and

comparing modeled ozone

concentration contours with monitored

ozone data. The model performance

evaluation was also based upon

statistical measures consisting of

comparing the modeled versus

monitored ozone. The "Unpaired Peak

Accuracy," "Normalized Bias," and,

"Gross Error" were all within the

suggested limits in the EPA Guideline.

EPA did not dismiss any measures or

analyses used by TNRCC for their model

performance evaluation, nor should

EPA weigh the graphical performance

more heavily than the other

performance measures. As indicated in

the State's modeling results for the

selected episode, the model responded

generally as expected to the diagnostic/

sensitivity analyses for the primary

episode day (9/8/93). Overall, these

analyses did not reveal any flaws in the

CAMx model formulation. In addition,

the statistical performance of the model

for the primary episode indicated the

model performed well. For all days

modeled, the graphical performance for

the majority of the monitor sites was

very good. For instance, the time-series

plots developed for each monitoring

station in the HG area indicated no

significant bias within the diurnal cycle

as well as good agreement between the

timing of the predicted and observed

ozone maxima.

EPA has recognized, however, the

graphical model performance for the

primary episode day of 9/8/93 indicates

the model at some locations

underestimated ozone and at other areas

the ozone was overestimated. Also, at

some locations, there are no ozone

monitors to substantiate the model's

performance. The ozone plume peaks

were simulated in different locations

than occurred with the monitored

results. EPA believes that most of the

error can be best explained by the

meteorological model having some

difficulty in replicating the wind speed

and direction. Discrepancies in wind

speed and direction not surprisingly

result in the model not predicting the

maximum ozone concentration in

precisely the right location, a possibility

noted by the commenter.

TNRCC has spent considerable effort

to better understand the land/sea breeze

phenomenon which has added a level of

complexity to the HG analysis not seen

any where else in the country (with the

exception of some lake breeze effects in

the Lake Michigan area). Emissions in

the HG area are emitted into the local

atmosphere where ozone formation

begins, later emissions and ozone

formed are transported out over the

warm air over the Gulf of Mexico where

the warmer temperatures further

activate the chemistry to form more

ozone which is then transported back

inland over the area. Current

meteorological models have had

difficulty in simulating this process. We

believe our understanding of the process

is sufficient, however, to interpret the

photochemical model results.

TNRCC and EPA intend to continue

evaluating how to more accurately

simulate the HG area's meteorological

conditions in the available models. The

need for further studies does not mean,

however, that the modeling relied upon

today was unable to estimate the

amount and type of emission reductions

needed for attainment. EPA believes

because the diagnostic/sensitivity tests

reveal no flaws in model formulations

and the model generally predicts the

right magnitude of the peak which is

confirmed by the statistical measures,

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that the model does provide an

acceptable tool for estimating the

amount of emissions reduction. It is

EPA's technical opinion that based on

the weight-of-evidence and the

modeling, the State's control strategy

should provide for attainment by

November 15, 2007.

Any new information derived from

the further studies and evaluation will

be incorporated by Texas into the SIP

revision modeling to be submitted to

EPA by May 1, 2004.

Comment: EPA previously expressed

its persistent concern about the model's

poor graphical performance. Now, EPA

has simply ignored the concern. The

commenter quoted a previous EPA

comment letter sent to the TNRCC

during the State's August 1999 public

comment period for its proposed SIP

revision. EPA's comment letter stated

that "due to the model's poor graphical

performance caution is warranted in

assessing the model's projected ozone

reduction due to NOx control

strategies."

Response: EPA disagrees that the

discrepancies in graphical performance

have been ignored. Texas made

numerous enhancements to its August

1999 proposed SIP attainment

demonstration modeling, based upon

EPA's comments. TNRCC has used a

new version of CAMx (i.e., version

2.03), which offers several

enhancements over the original version,

for the current modeling relied upon in

the submitted attainment demonstration

SIP revision. Also, major improvements

have been made to the base year

emission inventory. For instance,

biogenic emissions and the emissions

for diesel-powered construction

equipment, commercial marine vessel

emissions, airport ground support

equipment emissions, and industrial

equipment emissions have been

updated with more accurate

information. As a result, for all days

modeled, the graphical performance,

has been improved. For instance, the

time-series plots indicate the model

performance improved at a number of

monitoring stations in the HG area (i.e.,

Galveston site, HRM sites 3 and 4, Texas

City site and Clinton site). In addition,

the statistical model performance for the

current modeling which was similar to

that for the past modeling base case

indicated the model performed well. All

of the statistical parameters are within

the EPA suggested limits for the primary

episode day. EPA continues to believe,

taken together, the diagnostics,

sensitivity, statistical and graphical

performances of the model indicate the

base case model performance is

acceptable for assessing control strategy

effectiveness.

Further, in EPA's letter where we said

that caution is warranted in assessing

the projected ozone reduction to NOx

control strategies, EPA was cautioning

TNRCC that sufficient NOx reductions

should be provided to account for this

uncertainty in the model. We were not

saying that the graphical performance

meant the model was unacceptable for

assessing control strategy effectiveness.

Rather, we were advising the State to

take into account the graphical

performance, i.e., by ensuring the

control strategy took a more

conservative approach and erred on the

side of caution, in the amount of

required NOx reductions.

Comment: One commenter believes

that the modeling fails to account for

ozone spikes. The TNRCC's failure to

account for these spikes necessarily

means that the control strategy will not

attain the standard. Further, this results

in significant over estimates of NOx

emission reductions needed for

attainment. The commenter asserts that

the spikes are caused by highly reactive

VOCs, a theory it believes to be

supported by preliminary data and

findings of the Texas 2000 Air Quality

Study.

Response: Monitors measure

concentration at a point in space, and in

reality, these concentrations can vary

significantly over a grid cell or an area.

This is true especially for ozone if it is

contained in a narrow plume.

Inevitably, a grid type model will

smooth some natural phenomena

because natural conditions are averaged

over the volume of each grid cell. For

instance, model output represents a

volume average, typically 4km x 4km by

50 meter column. As a result, reasonable

comparisons between model predictions

and monitor observations are not

expected to match exactly. With

reasonable performance, time series

typically show similar diurnal cycles

but not exact concentration levels. As a

result, it is very difficult to obtain a

precise equality between modeled

concentration and monitored

concentration. This is to be expected

and does not necessarily call into

question the model's utility as a tool to

predict the level of emission reductions

needed to reach attainment. As stated in

previous comments, EPA believes the

model provides reasonable predictions

of ozone levels as confirmed by

comparisons with monitoring data and

therefore can provide an acceptable

estimate of the amount of emissions

needed for attainment. Certainly, any

difficulty the model has in replicating

rapid increases in ozone, does not

indicate that the model is calling for an "overestimate" of the amount of NOx

emission reductions needed for

attainment. Furthermore, even if the

model is shown during the mid-course

review to be overestimating the amount

of NOx emission reductions needed for

attainment, a State is always free to

adopt a control strategy that is more

stringent. See Union Electric v. EPA,

427 U.S. 246 (1976); Train v. NRDC, 421

U.S 60 (1975).

EPA is following with interest the

findings being presented from the Texas

2000 Air Quality Study, particularly the

information on concentrations of highly

reactive VOCs found in the ambient air

in the HG area. We understand Texas

intends to incorporate, as much as

possible, the findings of this study into

its next modeling effort, which is

currently underway and they expect to

submit by the end of 2002. This study

may improve our present understanding

of ozone formation in the HG area and

result in an improved effectiveness of

the control strategy being implemented

by the TNRCC. Nevertheless, based

upon all available evidence, the State's

control strategy shows attainment for

the HG area by the statutory deadline

and that the NOx emission reductions

are needed for attainment.

Comment: The 2007 post-control

strategy peak concentration is 141 ppb

at a monitoring site where the model

underestimated the monitored peak by

27 ppb during the validation run. Thus,

if the control strategy had been in effect

during the episode used for validating

the model, the actual ozone

concentration would likely have been

higher than 141 ppb.

Response: EPA disagrees. As is always

the case in a photochemical modeling

exercise, there are areas within the

simulation that do not correspond

exactly with observations. As discussed

in other comments, in this case, the

modeled wind fields tended to move the

ozone plumes formed on all four days

away from the areas where the highest

concentrations were observed. Although

the modeled peak on the primary

episode day (i.e., September 8, 1993)

was pushed west of the observed peak,

the results of the State's model

performance evaluation analyses for that

day indicate overall the model

performed well for the majority of the

monitoring sites. Misplacing the peak

does not necessarily mean the model is

providing inaccurate results or

predicting less ozone on that day. In

addition, this tendency does not, by

itself, mean that the model is not useful

for developing control strategies.

Therefore, again, we feel the model

provides a reasonable estimate of the

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emission reductions needed for

attainment.

Comment: A commenter criticized the

State model's inability to replicate

ozone levels on September 8, 1993 and

recommends that TNRCC estimate the

magnitude of emission reductions

needed for attainment from the

modeling results of September 10 and

11, 1993. One commenter believes the

best way to manage the risks of making

the wrong decision on the magnitude of

the needed controls is to base HG's

control strategy on the modeling

simulations that have the least

uncertainty. Though all four days of the

September 8-11, 1993 base case

simulation are characterized by poor

graphical performance, the greatest

uncertainties by far exist for September

8 and 9, 1993. Therefore, the commenter

believes that the control strategy should

be based on modeling results from

September 10 or 11, 1993.

Response: EPA disagrees. As

discussed in previous comments, we

believe the model performance is

acceptable on all four days.

Furthermore, EPA guidance

recommends that a minimum of three

episode days representing different

meteorological regimes be

modeled(Guideline for the Regulatory

Application of the Urban Airshed

Model, July 1991). With only four days

(i.e., Sept. 8-11), the number of episode

days being used by TNRCC for control

strategy development is only marginally

above the recommendation. Removing

days would not provide an appropriate

number of modeling days. EPA believes

that the September 8, 1993 episode day

chosen by TNRCC presents a reliable

and accurate modeling scenario for

ozone attainment demonstration in the

HG area. September 8, 1993 is the

controlling day because the

meteorological conditions experienced

that day require the most control to

reach attainment. September 8, 1993

also had the highest observed ozone

during the 4 day episode. Though

observed and predicted concentrations

do not match exactly, plausible inputs

resulted in plausible predictions. The

overall model performance for the

September 8, 1993 episode day meets

EPA criteria. Model performance on

September 11, 1993 was similar to that

observed on September 8, 1993, but is

not suitable to design control strategies,

since it was a Saturday. Controls based

on that day would still need to be

shown to be effective in controlling

ozone on a weekday, since the Saturday

emissions from mobile and area sources

differ considerably from their weekday

counterparts.

In addition, during episode selection,

TNRCC used a modification of the

Predominant Wind Direction (PWD)

method to analyze each potential

episode day. The wind analysis is based

on morning winds and afternoon winds.

The largest category was calm/calm

with 10 of 71 cases where most frequent

wind pattern for high ozone days

occurred in the HG region. The second

was calm/SSE with 9 cases. September

11, 1993 is in this category. The third

category was calm/ESE with 8 cases.

September 8, 1993 is in this category.

The PWD for September 10, 1993 is

NNW/ESE, which had one case.

Meanwhile, the PWD for September 9,

1993 is NNW/NNW, which had none.

Therefore, each of these episode days

covers different meteorological

conditions that are correlated with high

ozone levels in the HG area. To remove

one or more of the four episode days

would remove conditions that should be

evaluated to provide assurance that the

controls adopted in the SIP would be

expected to show attainment of the

NAAQS for potential meteorological

conditions conducive to ozone

formation in the HG area. In addition,

September 10, 1993 had an observed

peak value that was significantly lower

than the design value. Control strategies

based on absolute model predictions on

this day may not be sufficient to bring

the area into attainment. Therefore, no

days should be dropped from the State's

attainment demonstration.

Comment: Evaluating the equations

used to estimate the shortfall for

September 10 and 11, 1993, results in

gaps of 21 tpd and 37 tpd, respectively,

for which could be filled (with surplus)

from the list of gap measures given in

Table 6.1-2 of the proposal.

Response: As stated in previous

responses, September 8, 1993 must be

considered in the control strategy to

have confidence that the HG area will

attain under a commonly observed

meteorological condition. In any case,

after revisions to the inventory,

modeling now indicates that the

additional reductions estimated for

attainment on September 8, 1993 and

September 10, 1993 is 90.9 tpd and 93.7

tpd NOx, respectively; thus even on

September 10, 1993 the State has a

shortfall because Texas has only been

able to adopt measures to achieve 38

tons/day of additional measures.

Comment: TNRCC has presented no

evidence that the model is accurately

simulating NOx or VOC levels, or other

intermediate chemical species in the

vicinity of the modeled peaks.

Response: EPA disagrees. There is no

monitoring data in the area where the

modeled peak occurred to indicate one

way or the other how well the model

compared to measurements of NOx,

VOC and intermediate species. As a part

of the 1993 COAST study, VOC

concentrations were measured at two

locations in the HG nonattainment area,

and comparisons have been made

between modeled and monitored

concentrations. Similarly, for each of

the locations where NOx was

monitored, comparisons have been

made between modeled and monitored

concentrations. All of these

comparisons are included and discussed

in the '98 and '99 SIPs submitted to

EPA. Therefore, the attainment

demonstration we are approving relies

upon evidence that the model provided

results in a reasonable agreement with

the measurements considering that the

comparison is between a point

measurement and a simulated

volumetric average.

Monitors measure the concentration

at a point in space, and in practice,

these concentrations can vary

significantly from a volume average that

is 4km square and up to 50 meter high.

This is true for VOC and NOx

precursors, and is especially true for

precursors emitted by point sources.

The comparisons that have been made

indicate reasonable agreement between

monitored and modeled concentrations

given the considerations cited above

(see Appendix B entitled "Time Series

Plots of Observed, CAMx and UAM-V

Ozone Precursors Over the H/G

Modeling Domain for The Base Case

Simulation") of the Appendix B

(entitled "Modeling the Houston/

Galveston Ozone Attainment

Demonstration")) of the December 2000

SIP revision. Besides, the CAMx

photochemical model, which is an

ozone model, was developed and

optimized for that purpose. As

expected, some other chemical species

will not compare as well with ambient

data as does ozone. As mentioned

above, there are no monitoring data for

intermediate species, which have not

been recommended for use in validating

model results since they are not reliable.

Instead, these are often used to validate

model inputs (i.e., emission inventory),

if they become available.

Comment: Because of doubts

regarding the accuracy of the model

predictions, commenters recommend

that new emission controls be based on

proven cost-effective technology and

that stakeholders be given as much time

to implement controls as the Act allows.

The model simulations and basic

science that are the foundations of the

commission's control strategy are

currently not strong enough to support

the unproven, technically infeasible, or

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economically challenging measures in

the State's adopted control strategy.

Response: As described in previous

comments, we believe that the model

performance is acceptable and provides

an appropriate assessment of the

amount of emission reductions needed

for the HG area to attain. TNRCC and its

contractors have used state-of-thescience approaches to support the

adopted control strategy. All

appropriate and pertinent data

submitted during the State's comment

periods to improve the model were

incorporated or addressed by the State.

As discussed in our RACM and the

shortfall enforceable commitment

responses, it is EPA's position that the

control measures in the HG control

strategy are feasible. Therefore, it is our

position that the controls that have been

adopted by Texas have been shown to

be needed for the HG area to attain by

the statutory deadline. These controls

are being implemented as expeditiously

as practicable as required by the Act.

Comment: A commenter believes that

the TNRCC must address the risk that

the modeling uncertainties may have

led the commission to a wrong estimate

of the magnitude of emission reductions

needed to attain the ozone NAAQS.

Response: In the earlier submitted

SIPs, the effect of the uncertainty of the

emissions relative to the reductions

needed to attain the NAAQS was

addressed. This involved developing an

alternate emissions inventory that

reflected uncertainties, evaluating base

case model performance, and the effect

on the reductions needed to attain the

NAAQS with the future 2007 emissions.

This modeling showed that the control

path needed to attain the NAAQS did

not change (a NOx rather than VOCdirected control strategy), and that the

order of magnitude of the required

reductions did not change much. This

reinforced the necessity of obtaining the

level of NOx and VOC reductions

contained in this SIP revision.

The current approach does not show

attainment of the NAAQS at all

locations on all days that were modeled,

but uses modeling in combination with

weight of evidence to show that this

level of NOx and VOC reductions are

adequate to attain the standard.

Furthermore, the mid-course evaluation

can be used by Texas to reassess the

level of controls needed to attain the

NAAQS and ensure that timely progress

is being made toward attainment of the

standard.

Comment: One commenter supports

the recent contract commissioned by

Harris County with Environ. This work

will re-run the model with an alternate

meteorological simulation model in a

further attempt to address the nonperformance of the grid cells in

question.

Response: EPA understands that

TNRCC has worked with Harris County

and Environ on the alternate

meteorological simulation of the

episode modeled by the commission. It

takes substantial time and effort to

develop meteorological data to be run in

the photochemical model. After the data

are developed, the model results must

be evaluated for adequate

meteorological model performance.

Then the data must be used in the

photochemical model to evaluate basecase model performance with the new

data set. If the revised base case

modeling meets the performance

requirements, then the model will be

applied to the future 2007 emissions,

and various control scenarios modeled.

If these efforts provide a better

representation of meteorological

conditions in the HG area, then Texas

would address them in the mid-course

review.

Comment: Because of the model's

performance one commenter disagrees

with the following proposals:

(1) The model activities were

performed as outlined in the Protocols.

(2) The model activities were

performed according to the Guideline

For Regulatory Application of UAM.

(3) That the model performed within

EPA's recommended ranges.

(4) That the base case model is

suitable for control strategy testing.

(5) The proposal to accept the base

case model as a basis for attainment

demonstration modeling.

(6) The implicit finding that the

TNRCC validated the performance of the

base case modeling.

(7) That the simulated ozone contour

plots from the base case model depict

the area of ozone to be only "somewhat

at odds geographically" with the

monitors.

(8) The implicit finding that the base

case model fails only to "precisely

predict" the position of the cloud of

ozone geographically.

(9) That the base case model's

predicted position of the cloud of ozone

does not by itself, mean that the base

case model is not acceptable for control

strategy development.

(10) That the statistical measures from

the base case model are within EPA

recommended limits for all days of

September 8-11, 1993.

(11) That the results of the statistical

measures are within EPA recommended

ranges.

(12) That the spatial and temporal

patterns of ozone generated by the base

case model indicate it is acceptable for

use in the Attainment Demonstration.

(13) The diagnostic, sensitivity,

statistical and graphical performance of

the base case model indicate it is

acceptable for use in the Attainment

Demonstration.

(14) That reductions of NOx will be

most effective in bringing HGA into

attainment.

(15) That the quadratic equation used

by the TNRCC to determine the

additional amount of additional

emission reductions is consistent with

the 1999 guidance.

(16) That the quadratic equation is an

improvement over the 1999 guidance.

(17) That an additional 96 tons/day of

NOx emission reduction are necessary

to bring the HG area into attainment.

Response: As discussed in previous

comments, we believe the model

performed acceptably for use in control

strategy development. Therefore, we

disagree with the commenter and

continue to support the findings in the

conclusions from our proposed approval

that are cited above.

b. Model Inputs

Comment: Off-road shipping

emissions may be underestimated based

on preliminary results from the Texas

Air Quality 2000 Study.

Response: The State conducted a

study of actual shipping activity in the

HG area and applied EPA emission

factors to the activity to calculate the

shipping emissions. This site-specific

methodology is approved by EPA and

provides the best estimate of emissions

at this time. The results from the Texas

Air Quality Study 2000 are just now

being made available for analysis. The

results were not available to the State at

the time the SIP was prepared, and the

State needs additional time to evaluate

the data. It is hoped that the data can

be used by Texas for its mid-course

review. However, there is no evidence

presently before EPA showing that offroad shipping emissions were

underestimated by the State.

Comment: Industrial VOC emissions

are understated based on the

preliminary results of the Texas 2000

Air Quality Study.

Response: As discussed above,

TNRCC has followed EPA approved

methodologies in preparing its

emissions inventory. They have gone to

substantial effort to characterize all the

categories, including the industrial

emissions. This has included detailed

inventories from all of the major

emitters and inclusion of episodic

releases that were reported during the

1993 episode. We believe that the

emissions inventory is based on the best

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available techniques and data and meets

all EPA criteria and requirements.

TNRCC is continuing to work to

improve the inventory. This is a major

emphasis of the Texas 2000 Air Quality

study. We are aware some of the

preliminary findings of this study

indicate that industrial VOC emissions

may be understated. This indication is

based upon only preliminary findings at

this time, however. Texas has reached

no final conclusions. EPA will work

with TNRCC and other stakeholders to

address improvements to the inventory

so that the mid-course review modeling

incorporates any new and appropriate

data.

Comment: The commission and its

contractors have worked commendably

to develop what may be, in many

respects, the most accurate emissions

inventory ever used in photochemical

modeling. But major uncertainties still

exist in other respects and in the

model's representation of the chemical

reactions and meteorological processes

that determine the location, time, and

magnitude of high ozone levels in

Houston-Galveston.

Response: EPA disagrees that there

are major uncertainties with the

modeling. As discussed above in

previous responses, it is EPA's technical

position that the modeling adequately

represents the meteorological processes

for the HG area to allow its use for

control strategy purposes. Further, the

modeling is acceptable in its

representation of the chemical reactions

in the HG area. TNRCC and its

contractors have used state-of-thescience modeling approaches for

development of the meteorological

parameters used in the modeling.

The chemical algorithms used in the

modeling reflect the latest developments

in the state-of-the-science today. TNRCC

is currently investigating various

alternate chemical mechanisms, and

they plan to continue this activity with

analyses on the Texas 2000 study

results. If enhancements are identified

for the chemical algorithms, they can be

utilized in the mid-course evaluation,

and Texas would include them in the

mid-course review SIP.

Comment: It was noted that the 91 tpd

increase in point source NOx emissions

produced daily maximum ozone

increases ranging from 1.5 ppb (on

September 10) to 6.1 ppb (on September

11). The commenter also noted that the

91 tpd decrease in on-road mobile and

non-road mobile source NOx emissions

produced ozone decreases, relative to

HRM Strategy 1, ranging rom 6.9 ppb

(on September 11) to 10.8 ppb (on

September 8). From this, the commenter

sees relatively small benefits from the

commission's 90% point source control

proposal relative to a 75% point control

level, but sees greater benefits if the

same amount of incremental emissions

was reduced from mobile sources. It was

also noted that mobile source emission

reductions ranged from 1.1 to 7.0 times

more effective than point source NOx

reductions at reducing ozone levels

(given the ratio of mobile source to

point source NOx effectiveness). From

this, it follows that mobile source NOx

emission reductions are on average 3

times more effective at reducing ozone

levels than are point source emission

reductions.

Response: It is quite possible that

mobile source controls may be more

effective in reducing ozone levels for

certain nonattainment areas. The State,

however, analyzed the ensemble of

emission reductions modeled for the SIP

development for the HG area based on

an analysis of potential reductions

available from all of the various source

categories. As discussed in other

sections, Texas has adopted all RACM

for mobile as well as stationary sources.

It is not EPA's role to disapprove the

State's choice of control strategies if that

strategy will result in attainment of the

one-hour standard and meets all other

applicable statutory requirements. See

Union Electric v EPA, 427 U.S. 246

(1976); Train v. NRDC, 421 U.S 60

(1975).

Comment: One commenter states that

the modeled control strategy contained

in the Attainment Demonstration

includes measures that were modified

or removed from the SIP. The State did

not remodel to determine the impact of

these changes. Particularly, one measure

that was modified was a relaxation in

utility controls from 93% to 90%.

Another commenter supported the

changes to the required emission rates

for utilities because these revisions will

be offset by emission reductions from

grandfathered facilities in attainment

counties surrounding the HG area.

Response: During the State's

settlement negotiations and trial court

proceedings this summer in BCCA

Appeal Group, et al. v. Texas Natural

Resource Conservation Commission, et

al. in the District Court of Travis

County, Texas 250th Judicial District,

Cause No. GN1-00210, TNRCC

determined that the amount of control

for utilities should be reduced from

93% control to 90% control. Due to time

constraints and the necessity for

submitting an approvable attainment

demonstration in time for EPA action

before the NRDC consent decree

deadline of October 15, 2001 for

proposing a FIP in the absence of a fully

approved SIP, the revised utility

controls were not modeled by TNRCC.

TNRCC believes, and EPA agrees, that

any potential loss in ozone benefit from

reducing the utility point source

requirement will be de minimis, based

upon a review of certain information

gathered from the 2000 Texas Air

Quality Study. The information in the

Study indicates that Reliant Energy's

Parish power plant, located in the HG

area has an ozone production efficiency

which is 3 to 5 times smaller than the

ozone production efficiency expected

for the grand-fathered utility and nonutility sources based on Southern

Oxidant Study results for the Memphis

area. Ozone production efficiency is a

measure of the efficiency that a

particular NOx plume generates ozone

and is an indication of the reactivity of

the VOCs with which the NOx plume

comes in contact. The Parish plant is

located outside the central urban area

and apparently not in an area of highly

reactive biogenic emissions. The

remaining units affected by the reduced

control requirement are mainly peaking

units which deliver their increased

emissions during the hot afternoon

hours. Modeling for the construction

ban and lawn-care activities has

consistently shown that emissions in

the afternoon contribute less to ozone

formation in the HG area than emissions

generated in the morning.

To counterbalance the reduced

controls on utilities in the HG area,

Texas will control grandfathered

sources in East and Central Texas by

50% as required by recent State

legislation. These controls are in

addition to controls on utility sources,

Alcoa and Texas Eastman that are

already included in the model results.

These new controls would apply to all

non-utility sources, particularly

pipeline compressor station emissions

would be reduced by 50%. These

emission reductions can be expected to

achieve an ozone benefit in the HG area

to counterbalance the loss in NOx

reductions from the change in utilities

from 93-90% control.

Because the impact of the emission

increases for utilities in the HG area will

be small and there is a program to offset

these de minimis increases, EPA

believes it is appropriate to accept the

modeling and weight of evidence as

showing that attainment can be

achieved in the HG area by the statutory

deadline.

TNRCC currently intends to conduct

modeling based on the data results of

the Texas 2000 Air Quality Study, in

2002. Pursuant to the State's mid-course

review enforceable commitment, Texas

will submit a revised attainment

demonstration SIP by May 1, 2004 that

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will include modeling that incorporates

all scientific advancements made since

the recent SIP revisions, as appropriate.

Comment: As required by recent

legislation, the TNRCC repealed the

time-of-day construction ban. To

provide for the benefits that would have

been achieved by the construction ban,

the Texas legislature adopted a diesel

emission reduction incentive program.

However, TNRCC failed to model the

control strategy with the diesel engine

incentive program replacing the

morning construction ban. EPA may not

approve the photochemical modeling

and the subsequent gap calculation

because these emission reductions were

revised and not modeled.

Response: Texas legislation, enacted

in May, 2001, established a diesel

emission reduction incentive program

and required TNRCC to repeal its rules

for a morning construction ban and

accelerated purchase of diesel

equipment. Due to time constraints and

the necessity for submitting an

approvable attainment demonstration in

time for EPA action before the NRDC

consent decree deadline of October 15,

2001 for proposing a FIP in the absence

of a fully approved SIP, the State could

not specifically model the diesel engine

incentive program in their attainment

demonstration. The TNRCC had,

however, conducted numerous control

scenario modeling runs, which

combined federal, state and local

measures, designed to provide

significant ozone reductions in the area.

The results of one control scenario

modeling run indicated that the benefit

of the construction ban was

approximately 3 ppb of ozone. Based on

the quadratic curve, TNRCC estimated

that this 3 ppb reduction in the ozone

concentration level was equivalent to a

6.7 tpd reduction of NOx emissions.

EPA believes the State used acceptable

procedures for determining this

estimate. As discussed in other

responses to comments regarding the

diesel engine incentive Program, EPA

believes that this program will achieve

greater NOx emission reductions in the

HG area than 6.7 tpd. EPA and State

calculations project that this new

program will cover the loss in

reductions from the construction ban

and the accelerated purchase rules, and

also fill a portion of the shortfall. EPA

believes that the incentive program will

likely produce somewhat greater

benefits than the morning construction

ban because it can achieve emission

reductions not only from construction

diesel equipment but also from

additional categories such as tug/tow

boats which are located in the portion

of the HG area where the highest ozone

levels often occur. In addition, TNRCC

currently intends to conduct modeling

based on the data results of the 2000

Texas Air Quality Study, in 2002.

Pursuant to the State's mid-course

review enforceable commitment, Texas

will submit a revised attainment

demonstration SIP by May 1, 2004 that

will include modeling that incorporates

all scientific advancements made since

the recent SIP revisions, as appropriate.

Comment: TNRCC has not correctly

estimated point source growth in

attainment counties of East and Central

Texas. The commenter provided Public

Utility Commission estimates of new

capacity.

Response: As noted by the

commenter, Appendix H of the SIP

contains documentation of the projected

newly permitted growth. Texas

examined all of the permits issued by

TNRCC for the 8 county HG area and the

counties within 100 miles of the HG

area. Permitted projects in this area

were included in the model's future

base inventory. EPA believes that Texas

used a reasonable method of estimating

the growth for the area most likely to

impact the HG area's air quality.

Comment: One commenter stated the

attainment and rate of progress

demonstrations are flawed because they

assume a fleet mix that does not

accurately reflect the growing

proportion of sport utility vehicles and

gasoline trucks. EPA and the states have

not followed a consistent practice in

updating SIP modeling to account for

changes in vehicle fleets. EPA cannot

rationally approve SIPs that are based

on such materially inaccurate

assumptions. Continued use of outdated assumptions is inconsistent with

the duty imposed by the Act section

182(a)(3) to triennially update the

emission inventory. If the motor vehicle

inventory has not been updated in

preparing the current SIP submission,

the SIP should be disapproved. One

commenter compared the numbers from

the Dallas/Fort Worth area to the HG

area and provided the results of a

Contractor Study of vehicle registration

data to support its claims that the

portion of SUVs in the Houston fleet are

understated.

Response: The November 1999 HG

area attainment demonstration SIP's

associated mobile source budgets were

based on fleet mix information updated

based on a December 1998 Texas

Transportation Institute (TTI) Report,

"Development of Gridded On-road

Inventory for the Houston/Galveston

Ozone Nonattainment Area," found in

Appendix G of the November 1999 SIP

revision. TTI relied on vehicle

classification count data recorded on

roadways throughout the 8-county area

by Texas Department of Transportation

(TxDOT) personnel utilizing automatic

vehicle classification (AVC) equipment.

This equipment is set up along the

roadway and is calibrated to classify all

of the passing vehicles into thirteen

vehicle types. Due to the fact that AVC

equipment cannot distinguish vehicle

fuel type on the roadway, the various

vehicle categories are then separated out

into their gasoline and diesel

classifications, based on a combination

of MOBILE5 defaults and county vehicle

registration data. The fleet mix

information was based on vehicle

counts that were a mix of 1996 data for

week days, and 1993 and 1998 data for

weekends. This was the most recent

data available when Texas submitted

the attainment demonstration SIP for

the HG area in November 1999.

The December 2000 SIP included data

provided by TTI from the most recently

available observed AVC data which was

from 1997, 1998, and 1999. In order to

avoid year-to-year fluctuations in the

data set, TTI averaged the AVC data

from these three years in order to obtain

a more recent VMT mix, which was

used in the revised 2007 inventory. This

data was used to update the modeling

provided in December 2000. At the time

the TNRCC modeling for the December

2000 SIP was being completed, this data

set was the most recent data available.

The data used for the modeling is more

recent than the most recently completed

periodic inventory (1996). The 1999

inventory is expected to be completed

soon and include the more recent data.

EPA requires the most recent

available data to be used, but we do not

require it to be updated on a specific

schedule. Therefore, different SIPs base

their fleet mix on different years of data.

Our guidance does not suggest that SIPs

should be disapproved on this basis.

Nevertheless, we do expect that

revisions to these SIPs that are

submitted using MOBILE6 (as required

in those cases where the SIP is relying

on emissions reductions from the Tier 2

standards) will use updated vehicle

registration data appropriate for use

with MOBILE6, whether it is updated

local data or the updated national

default data that will be part of

MOBILE6.

In the November 3, 1999, "Guidance

on Motor Vehicle Emissions Budgets in

One-Hour Ozone Attainment

Demonstrations," we state that, when

developing motor vehicle emissions

budgets, the MOBILE inputs (including

vehicle fleet characteristics) should be

appropriate and up-to-date as outlined

in EPA's guidance on SIP inventories

and the MOBILE user's guide. The SIP

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has been based on the most recent

information and meets the intended

purpose of the existing guidance.

A particular concern raised by a

commenter was that registration data

from the TXDOT data base indicate that

13.2% of the vehicles registered in the

8 county area are light duty gas trucks

two (LDGT2) as compared to the VMT

mix figures provided by TTI which

project this category at only 4.5% of the

mix. The commenter also pointed out

that LDGT2 were estimated as 11.4% of

the mix for the Dallas/Fort Worth area

SIP and the EPA national default is

8.8%. The LDGT2 category includes

large SUV and pickups. The percentage

of miles traveled by these vehicles is

important because they currently have

higher emission standards than

passenger cars.

The EPA believes that vehicle

registration data alone does not

necessarily represent the most accurate

estimation of fleet mix characteristics

that actually exist on the current

transportation network system. The best

possible approach would be to use a

combination of both AVC and

conventional registration data. However,

EPA believes that field AVC data of

vehicles traveling on the roadways

throughout the 8-county area provide a

reasonable estimate of the types of

vehicles and distance these vehicles are

driven. This is because vehicles from

some categories are driven more than

other categories. Heavy Duty Diesel

Trucks, in particular, account for more

miles than the values that may be

reflected by the vehicular registration

process. Registration distribution is

different than VMT mix and actual data

is the best possible information. In

addition, while one might expect the

numbers to be similar between DFW

and Houston, they are two different

cities with many different social and

economic variables. One cannot

presume Houston to be the same as

DFW when the location specific data

does not support this conclusion.

It is worth noting that the Tier II

standards will eliminate the difference

between (i) passenger car and (ii) larger

truck and SUV emissions standards.

Therefore, as Tier II vehicles become

more widespread, possible

discrepancies in the percentage of

trucks and SUVs will become less

important for air quality planning

purposes. The Tier II standards begin

taking affect in new vehicle

manufactured in 2004.

The EPA has encouraged and required

use of the latest assumptions and data

in forecasting the on-road mobile source

emissions whenever possible. Updating

the data and using the latest information

is a continuous planning process which

does not end with this SIP and will

continue in the future for emissions

inventory updates, SIP development,

and for conducting conformity

determinations. In addition, the

refinements in the emissions inventory

procedures and use of the MOBILE6

model will further enhance not only the

VMT mix issue but also other

parametric inputs in computing the onroad mobile source emissions. However,

it must be recognized that because of

many constraints associated with

availability and timing of new

information, the process of updating the

vehicular and other data does not

necessarily follow the SIP development

cycle, and thus there is likely to be a lag

time. The EPA is committed to ensure

that the best available data are used in

any air quality analysis and this SIP is

no exception. Therefore, based on the

information documented in the SIP and

the EPA's current guidance, the EPA

believes that Texas has made reasonable

assumptions and has utilized the most

recent available data in determining the

on-road mobile source emissions.

Comment: The model's failure to

account for episodic emissions events is

a serious flaw. The commenter cited a

description in the SIP of a butadiene

release as evidence of this problem.

Response: TNRCC made every effort

to account for episodic emissions in the

model. It surveyed companies to

determine if any specific events

occurred during the modeling episode,

including reported upset events. The

reported episodic emissions were

included in the modeling.

Consequently, we believe Texas used

the best information available to address

episodic emissions and therefore, the

SIP is approvable.

The growing availability of ambient

VOC data from the Photochemical

Assessment Monitoring Stations

(PAMS) network, however, indicates

that more may need to be done in this

area. The butadiene release cited by the

commenter is a case in point. In

addition, the Texas 2000 Air Quality

Study is providing a wealth of

information that is just being analyzed.

This data, it is hoped, will shed more

light on the impact of episodic

emissions on ozone levels. The midcourse review SIP, due to EPA in May

2004, will contain the most recent data

available for that SIP's planning.

Comment: EPA should investigate the

impact on the plan of any changes being

considered in the EPA's 90-day review

of the New Source Review (NSR)

progam. The commenter is concerned

that relaxed NSR requirements may

affect the level of emissions from point

sources in the Region.

Response: The 90-day review of the

NSR program is not complete at this

time. It is expected that any

modifications to the Federal NSR

provisions will include provisions for

strict caps for the pollutants and

therefore should be as stringent as the

present NSR rule. Moreover, any

changes made through this review will

not affect the NSR rules approved for

the HG area in the current SIP. If Texas

determines that the HG area rules

should be modified in response to the

90-day review, Texas will need to

submit those changes as a SIP revision

and under Section 110(1) of the Act,

EPA will need to consider the effect of

those changes on the HG area's

attainment demonstration.

c. Weight of Evidence Analysis

Comment: Several commenters stated

that the weight of evidence approach

does not demonstrate attainment or

meet CAA requirements for a modeled

attainment demonstration. Commenters

added several criticisms of various

technical aspects of the weight of

evidence approach, including certain

specific applications of the approach to

particular attainment demonstrations.

These comments are discussed in the

following response.

Response: Under section 182(c)(2) and

(d) of the Act, serious and severe ozone

nonattainment areas were required to

submit by November 15, 1994,

demonstrations of how they would

attain the one-hour standard. Section

182(c)(2)(A) provides that "[t]his

attainment demonstration must be based

on photochemical grid modeling or any

other analytical method determined by

the Administrator, in the

Administrator's discretion, to be at least

as effective." As described in more

detail below, the EPA allows states to

supplement their photochemical

modeling results, with additional

evidence designed to account for

uncertainties in the photochemical

modeling, to demonstrate attainment.

This approach is consistent with the

requirement of section 182(c)(2)(A) that

the attainment demonstration "be based

on photochemical grid modeling,"

because the modeling results constitute

the principal component of EPA's

analysis, with supplemental information

designed to account for uncertainties in

the model. This interpretation and

application of the photochemical

modeling requirement of section

182(c)(2)(A) finds further justification in

the broad deference Congress granted

EPA to develop appropriate methods for

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determining attainment, as indicated in

the last phrase of section 182(c)(2)(A).

The flexibility granted to EPA under

section 182(c)(2)(A) is reflected in the

regulations EPA promulgated for

modeled attainment demonstrations.

These regulations provide, "The

adequacy of a control strategy shall be

demonstrated by means of applicable air

quality models, data bases, and other

requirements specified in (40 CFR part

51, Appendix W) (Guideline on Air

Quality Models)."' 40 CFR 51.112(a)(1).

However, the regulations further

provide, "Where an air quality model

specified in appendix W. * * * is

inappropriate, the model may be

modified or another model substituted

(with approval by EPA, and after) notice

and opportunity for public comment.

* * *." Appendix W, in turn, provides

that, "The Urban Airshed Model (UAM)

is recommended for photochemical or

reactive pollutant modeling applications

involving entire urban areas," but

further refers to EPA's modeling

guidance for data requirements and

procedures for operating the model. 40

CFR part 51, Appendix W, section

6.2.1.a. The modeling guidance

discusses the data requirements and

operating procedures, as well as

interpretation of model results as they

relate to the attainment demonstration.

This provision references guidance

published in 1991, but EPA envisioned

the guidance would change as we

gained experience with model

applications, which is why the guidance

is referenced, but does not appear, in

Appendix W. With updates in 1996 and

1999, the evolution of EPA's guidance

has led us to use both the

photochemical grid model, and

additional analytical methods approved

by EPA.

The modeled attainment test

compares model predicted one-hour

daily maximum ozone concentrations in

all grid cells for the attainment year to

the level of the NAAQS. The results

may be interpreted through either of two

modeled attainment or exceedance tests:

A deterministic test or a statistical test.

Under the deterministic test, a predicted

concentration above 0.124 parts per

million (ppm) ozone indicates that the

area is expected to exceed the standard

in the attainment year and a prediction

at or below 0.124 ppm indicates that the

area is expected to not exceed the

standard. Under the statistical test,

attainment is demonstrated when all

1 The August 12, 1996 version of "Appendix W

to Part 51-Guideline on air Quality Models" was

the rule in effect for these attainment

demonstrations. EPA is proposing updates to this

rule which will not be in effect until the new rule

is promulgated.

predicted (i.e., modeled) one hour ozone

concentrations inside the modeling

domain are at, or below, an acceptable

upper limit above the NAAQS permitted

under certain conditions (depending on

the severity of the episode modeled).2

In 1996, EPA issued guidances to

update the 1991 guidance referenced in

40 CFR part 50, App. W, to make the

modeled attainment test more closely

reflect the form of the NAAQS (i.e., the

statistical test described above), to

consider the area's ozone design value

and the meteorological conditions

accompanying observed exceedances,

and to allow consideration of other

evidence to address uncertainties in the

modeling databases and application.

When the modeling does not

conclusively demonstrate attainment,

EPA has concluded that additional

analyses may be presented to help

determine whether the area will attain

the standard. As with other predictive

tools, there are inherent uncertainties

associated with air quality modeling

and its results. The inherent

imprecision of the model means that it

may be inappropriate to view the

specific numerical result of the model as

the only determinant of whether the SIP

controls are likely to lead to attainment.

The EPA's guidance recognizes these

limitations, and provides a means for

considering other evidence to help

assess whether attainment of the

NAAQS is likely to be achieved. The

process by which this is done is called

a weight of evidence determination.

Under a weight of evidence

determination, the state can rely on, and

EPA will consider in addition to the

results of the modeled attainment test,

other factors such as other modeled

output (e.g., changes in the predicted

frequency and pervasiveness of onehour ozone NAAQS exceedances, and

predicted change in the ozone design

value); actual observed air quality

trends (i.e. analyses of monitored air

quality data); estimated emissions

trends; and the responsiveness of the

model predictions to further controls.

In 1999, EPA issued additional

guidance 4 5 that makes further use of

2 Guidance on the Use Of Modeled Results to

Demonstrate Attainment of the Ozone NAAQS.

EPA-454/B-95-007, June 1996.

3 Ibid.

45 "Guidance for Improving weight of Evidence

Through Identification of Additional Emission

Reductions, Not Modeled." U.S. Environmental

Protection Agency, Office of Air Quality Planning

and Standards, Emissions, Monitoring, and

Analysis Division, Air Quality Modeling Group,

Research Triangle Park, NC 27711. November 1999.

Web site: http://www.epa.govlttnlscram. http://

www.ncdc.noaa.gov/ol/climate/research/1999/

perspectives.html and "Regional Haze and

Visibility in the Northeast U.S.", NESCAUM at

http://www.nescaum.org/pdf/pubslist.pdf

model results for base case and future

emission estimates to predict a future

design value. This guidance describes

the use of an additional component of

the weight of evidence determination,

which requires, under certain

circumstances, additional emission

reductions that are or will be approved

into the SIP, but that were not included

in the modeling analysis, that will

further reduce the modeled design

value. An area is considered to monitor

attainment if each monitor site has air

quality observed ozone design values

(4th highest daily maximum ozone

using the three most recent consecutive

years of data) at or below the level of the

standard. Therefore, it is appropriate for

EPA, when making a determination that

a control strategy will provide for

attainment, to determine whether or not

the model predicted future design value

is expected to be at or below the level

of the standard. Since the form of the

one-hour NAAQS allows exceedances, it

did not seem appropriate for EPA to

require the test for attainment to be "no

exceedances" in the future model

predictions. The method outlined in

EPA's 1999 guidance uses the highest

measured design value from all sites in

the nonattainment area for each of three

years. 6 The three year "design value"

represents the air quality observed

during the time period used to predict

ozone for the base emissions. This is

appropriate because the model is

predicting the change in ozone from the

base period to the future attainment

date. The three yearly design values

(highest across the area) are averaged to

account for annual fluctuations in

meteorology. The result is an estimate of

an area's base year design value. The

base year design value is multiplied by

a ratio of the peak model predicted

ozone concentrations in the attainment

year (i.e., average of daily maximum

concentrations from all days modeled)

to the peak model predicted ozone

concentrations in the base year (i.e.,

average of daily maximum

6 A commenter criticized the 1999 guidance as

flawed on grounds that it allows the averaging of

the three highest air quality sites across a region,

whereas EPA's 1991 and 1996 modeling guidance

requires that attainment be demonstrated at each

site. This has the effect of allowing lower air quality

concentrations to be averaged against higher

concentrations thus reducing the total emission

reduction needed to attain at the higher site. The

commenter's concern is misplaced. EPA relies on

this averaging only for purposes of determining one

component, i.e.,-the amount of additional

emission reductions not modeled-of the weight of

evidence determination. The weight of evidence

determination, in turn, is intended to be a

qualitative assessment of whether additional factors

(including the additional emissions reductions not

modeled), taken as a whole, indicate that the area

is more likely than not to attain.

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concentrations from all days modeled).

The result is an attainment year design

value based on the relative change in

peak model predicted ozone

concentrations from the base year to the

attainment year. Modeling results also

show that emission control strategies

designed to reduce areas of peak ozone

concentrations generally result in

similar ozone reductions in all core

areas of the modeling domain, thereby

providing some assurance of attainment

at all monitors.

In the event that the attainment year

design value is above the standard, the

1999 guidance provides a method for

identifying additional emission

reductions, not modeled, which at a

minimum provide an estimated

attainment year design value at the level

of the standard. This step uses a locally

derived factor which assumes a

relationship between ozone and the

precursors.

Although a commenter criticized this

technique for estimating ambient

improvement because it does not

incorporate complete modeling of the

additional emissions reductions, the

regulations do not mandate nor does

EPA guidance suggest that States must

model all control measures being

implemented. Moreover, a component

of this technique-the estimation of

future design value, should be

considered a model predicted estimate.

Therefore, results from this technique

are an extension of "photochemical

grid" modeling and are consistent with

section 182(c)(2)(A). Also, a commenter

believes EPA has not provided sufficient

opportunity to evaluate the calculations

used to estimate additional emission

reductions. EPA provided a 60-day

period for comment on the methodology

and calculations in December 1999 and

a 30-day comment period in July 2001

on the HG area's calculated shortfall.

Texas also provided a public comment

period and public hearings in

September, 2000 on this issue.

A commenter states that application

of the method of attainment analysis

used for the December 16, 1999 NPRs

will yield a lower control estimate than

if we relied entirely on reducing

maximum predictions in every grid cell

to less than or equal to 124 ppb on every

modeled day. However, the

commenter's approach may

overestimate needed controls because

the form of the standard allows up to 3

exceedances in 3 years in every grid

cell. If the model over predicts observed

concentrations, predicted controls may

be further overestimated. EPA has

considered other evidence, as described

above through the weight of evidence

determination.

When reviewing a SIP, the EPA must

make a reasonable determination that

the control measures adopted more

likely than not will lead to attainment.

Under the Weight of evidence

determination, EPA has made this

determination for the HG area based on

all of the information presented by the

State and available to EPA. The

information considered includes model

results for the majority of the control

measures. Though all measures were not

modeled, EPA reviewed the model's

response to changes in emissions as

well as observed air quality changes to

evaluate the impact of additional

measures, not modeled. EPA's decision

was further strengthened by the State's

commitment to check progress towards

attainment in 2004 and to adopt

additional measures, if the anticipated

progress is not being made.

A commenter further criticized EPA's

technique for estimating the ambient

impact of additional emissions

reductions not modeled on grounds that

EPA employed a rollback modeling

technique that, according to the

commenter, is precluded under EPA

regulations. The commenter explained

that 40 CFR part 51, App. W, section

6.2.1.e. provides, "Proportional

(rollback/forward) modeling is not an

acceptable procedure for evaluating

ozone control strategies." Section 14.0

of appendix W defines "rollback" as "a

simple model that assumes that if

emissions from each source affecting a

given receptor are decreased by the

same percentage, ambient air quality

concentrations decrease

proportionately." Under this approach if

20% improvement in ozone is needed

for the area to reach attainment, it is

assumed a 20% reduction in VOC

would be required.

The "proportional rollback" approach

is based on a purely empirically/

mathematically derived relationship.

EPA did not rely on this approach in its

evaluation of the attainment

demonstrations. The prohibition in

Appendix W applies to the use of a

rollback method which is empirically/

mathematically derived and

independent of model estimates or

observed air quality and emissions

changes as the sole method for

evaluating control strategies. For the

demonstrations, EPA used a locally

derived (as determined by the model

and/or observed changes in air quality)

relationship of the change in emissions

to change in ozone to estimate

additional emission reductions to

achieve an additional increment of

ambient improvement in ozone. For

example, if monitoring or modeling

results indicate that ozone was reduced

by 25 ppb during a particular period,

and that VOC and NOx emissions fell by

20 tons per day and 10 tons per day

respectively during that period, EPA

developed a relationship for ozone

improvement related to reductions in

VOC and NOx. This formula assumes a

quadratic relationship between the

precursors and ozone for a small

amount of ozone improvement, but it is

not a "proportional rollback" technique.

Further, EPA uses these locally derived

adjustment factors as a component to

estimate the extent to which additional

emissions reductions-not the core

control strategies-would reduce ozone

levels and thereby strengthen the weight

of evidence test. EPA uses the UAM to

evaluate the core control strategies. This

limited use of adjustment factors is

more technically sound than the

unacceptable use of proportional

rollback to determine the ambient

impact of the entire set of emissions

reductions required under the

attainment SIP. The limited use of

adjustment factors is acceptable for

practical reasons: It obviates the need to

expend more time and resources to

perform additional modeling. In

addition, the adjustment factor is a

locally derived relationship between

ozone and its precursors based on air

quality observations and/or modeling

which is more consistent with

recommendations referenced to in

Appendix W and does not assume a

direct proportional relationship between

ozone and its precursors. In addition,

the requirement that areas perform a

mid-course review (a check of progress

toward attainment) provides a margin of

safety.

A commenter expressed concerns that

EPA used a modeling technique

(proportional rollback) that was

expressly prohibited by 40 CFR part 51,

Appendix W, without expressly

proposing to do so in a notice of

proposed rulemaking. However, the

commenter is mistaken. As explained

above, EPA did not use or rely upon a

proportional rollback technique in this

rulemaking, but used UAM to evaluate

the core control strategies and then

applied its WOE guidance. Therefore,

because EPA did not use an "alternative

model" to UAM, it did not trigger an

obligation to modify Appendix W.

Furthermore, EPA did propose to use

the November 1999 guidance,

"Guidance for Improving Weight of

Evidence Through Identification of

Additional Emission Reductions, Not

Modeled," in the December 16, 1999

NPR and has responded to all comments

received on the application of that

guidance elsewhere in this document.

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A commenter also expressed concern

that EPA applied unacceptably broad

discretion in fashioning and applying

the WOE determinations. For all of the

attainment submittals proposed for

approval in December 1999 concerning

serious and severe ozone nonattainment

areas, EPA first reviewed the UAM

results. In all cases, the UAM results did

not pass the deterministic test. In two

cases-Milwaukee and Chicago-the

UAM results passed the statistical test;

in the rest of the cases, the UAM results

failed the statistical test. The UAM has

inherent limitations that, in EPA's view,

were manifest in all these cases. These

limitations include: Only selected time

periods were modeled, not the entire

three-year period used as the definitive

means for determining an area's

attainment status. Also, there are

inherent uncertainties in the model

formulation and model inputs such as

hourly emission estimates, emissions

growth projections, biogenic emission

estimates, and derived wind speeds and

directions. As a result, for all areas, even

Milwaukee and Chicago, EPA examined

additional analyses to indicate whether

additional SIP controls would yield

meaningful reductions in ozone values.

These analyses did not point to the need

for additional emission reductions for

Springfield, Greater Connecticut,

Metropolitan Washington DC, Chicago

and Milwaukee, but did point to the

need for additional reductions, in

varying amounts, in the other areas. As

a result, the other areas submitted

control requirements to provide the

indicated level of emissions reductions.

EPA applied consistent methodologies

in these areas, but because of differences

in the application of the model to the

circumstances of each individual area,

the results differed on a case-by-case

basis.

The commenter also complained that

EPA has applied the WOE

determinations to adjust modeling

results only when those results indicate

nonattainment, and not when they

indicate attainment. First, we disagree

with the premise of this comment: EPA

does not apply the WOE factors to

adjust model results. EPA applies the

WOE factors as additional analysis to

compensate for uncertainty in the air

quality modeling. Second, EPA has

applied WOE determinations to all of

the attainment demonstrations proposed

for approval in December 1999.

Although for most of them, the air

quality modeling results by themselves

indicated nonattainment, for two

metropolitan areas-Chicago and

Milwaukee, including parts of the States

of Illinois, Indiana, and Wisconsin, the

air quality modeling did indicate

attainment on the basis of the statistical

test.

For the HG area, the primary

evidence, in addition to the modeled

control strategy that the HG area will

attain the standard, is the estimation of

the ozone benefits from the emission

reductions that were not modeled (i.e.,

approximately 90.9 tpd). Additional

evidence for the HG area is provided by

the good model performance which

lends credence to the results. Further

evidence is the substantial reduction in

the area of nonattainment projected for

the control strategy case. The State

showed the modeled control strategy

resulted in a 93.6% reduction in grid

cells over the standard. Finally, the

state's commitment to perform a midcourse review provides further

confidence that the State's overall plan

will result in attainment by 2007.

Collectively, the above information

supported EPA's decision. These

determinations were made based on

EPA's best understanding of the

problem and relied on a qualitative

assessment as well as quantitative

assessments of the available

information.

The commenter further criticized

EPA's application of the weight of

evidence determination on grounds that

EPA ignores evidence indicating that

continued nonattainment is likely, such

as, according to the commenter,

monitoring data indicate that ozone

levels in many cities during 1999

continue to exceed the NAAQS by

margins as wide or wider than those

predicted by the UAM model. EPA did

consider the monitoring data along with

other information in these

determinations. When reviewing the

monitoring data, EPA considered other

factors. For example, high monitoring

values may have occurred for many

reasons including, fluctuations due to

changes in meteorology and lack of

emission reductions. The 1999 monitor

values do not reflect several control

programs, both local and the regional

which are scheduled for

implementation in the next several

years. And the 1999 meteorology in the

Northeast was such that July 1999 was

one of the warmest (ranked 9th) ever

experienced since 1895. 7 In addition to

the heat, the middle and southern

portions of the Northeast were also drier

than average during this month. This

information supports EPA's belief that

the high exceedances observed in 1999

7http://www.ncdc.noaa.gov/ol/climate/research/

1999/perspectives.html and "Regional Haze and

Visibility in the Northeast U.S.", NESCAUM at

http://www.nescaum.org/pdf/pubslist.pdf

are not likely to reoccur frequent

enough to cause a violation, once the

controls adopted in these SIP's are

implemented. There is little evidence to

support the statement that ozone levels

in many cities during 1999 continue to

exceed the NAAQS by margins as wide

or wider than those predicted by the

UAM. Since areas did not model 1999

ozone levels using 1999 meteorology

and 1999 emissions which reflect

reductions anticipated by control

measures, that are or will be approved

into the SIP, there is no way to

determine how the UAM predictions for

1999 compare to the 1999 air quality.

Therefore, we can not determine

whether or not the monitor values

exceed the NAAQS by a wider margin

than the UAM predictions for 1999. In

summary, there is little evidence to

support the conclusion that high

exceedances in 1999 will continue to

occur after adopted control measures are

implemented.

In addition, the commenter argued

that in applying the weight of evidence

determinations, EPA ignored factors

showing that the SIPs under-predict

future emissions, and the commenter

included as examples certain mobile

source emissions sub-inventories. EPA

did not ignore possible under-prediction

in mobile emissions. EPA is presently

evaluating mobile source emissions data

as part of an effort to update the

computer model for estimating mobile

source emissions. EPA is considering

various changes to the model, and is not

prepared to conclude at this time that

the net effect of all these various

changes would be to increase or

decrease emissions estimates. For the

HG area's attainment demonstration SIP

that relies on the Tier 2/Sulfur program

for attainment (and reflects these

programs in its motor vehicle emissions

budgets), Texas has committed to revise

the motor vehicle emissions budgets

after the MOBILE6 model is officially

released by EPA. EPA will work with

Texas if the new emission estimates

raise issues about the sufficiency of the

present attainment demonstration. If

analysis indicates additional measures

are needed, EPA will take appropriate

action.

Comment: The 1999 Guidance

Document was criticized on grounds

that EPA could not apply it, by its

terms, to the Houston area because the

result of such application would have

been absurd. The commenter added that

the technique used to estimate the

additional needed emission reductions

for the Houston area does not identify

a sufficient level of emission reductions

to reach attainment. In addition,

according to the commenter, the

2001/ Rules and Regulations 57173

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technique used for the Houston area is

substantially at variance with the UAM

modeling analyses performed by Texas

and submitted to EPA as SIP revisions.

Specifically, Texas showed in its May

1998 SIP submission that emissions in

the Houston area would have to be

reduced to 230 tons per day to attain. By

contrast, according to the commenter,

EPA's combination of techniques would

allow 305 tons per day of emissions,

and yet EPA claims that the area will

attain with even this higher level of

emissions. The commenters believe that

Texas should not be able to use the gap

calculation when modeling exists that

demonstrates how attainment can be

achieved. A commenter also asserted

that Texas should not be able to use a

gap calculation method that differs from

what other areas must use and the gap

calculation fails to account for real

world chemistry.

Response: Direct application of the

two methods discussed in EPA's

November 1999 guidance, using

available data for the HG area, produced

a mathematical impossibility. The

results indicated that all ozone

precursor emissions would have to be

reduced to less than zero. Thus, the two

methods described in the 1999 guidance

are not directly applicable to Houston.

The 1999 guidance describes two

techniques for estimating additional

levels of emission reductions. Both

techniques (methods) described in the

1999 guidance are based on the

assumption that EPA can estimate the

relationship between ozone and its

precursors. EPA Region 6 and TNRCC

worked together to develop a revised

method that is consistent with the

concepts in the 1999 guidance for

estimating the relationship, but

applicable to the Houston area's

modeling results. The methods in the

guidance use a linear extrapolation of

model results to determine expected

ozone benefits from additional

precursor reductions. The method for

the HG area is also an extrapolation of

model results. Because, the method for

the HG area extends model results, it

does, in fact account for real world

chemistry. Instead of a linear

extrapolation, however, a quadratic

extrapolation was developed based on

the results of three of the modeling runs.

A quadratic extrapolation is necessary

because of the non-linearity of the ozone

response to NOx reductions in the HG

area. Therefore, the method is a

refinement in the methods described in

the 1999 guidance, since it is based on

the most recently available modeling for

the Houston area. The factors used in

the method for the Houston area are

based on model results for the majority

of the control measures and,

consequently, are scientifically sound

for the HG area. We believe this

approach is consistent with the intent

and criteria of the 1999 guidance and,

in the case of the Houston area, gives a

better approximation (than the other

two methods) of the amount of emission

reductions that will be necessary to

achieve the standard. Therefore, this

method fulfills the purposes of the EPA

guidance, and it is as rigorous, if not

more rigorous, than the two methods

discussed in the 1999 guidance. As a

result, EPA concludes that the State of

Texas used an acceptable method under

the November 1999 guidance and

applied it correctly.

In the strategy upon which the NOx

mobile vehicle emissions budget is

based, Texas modeled NOx emissions

reduced to a level of approximately 396

t/d. Since the model predicted future

ozone design values above the standard,

using the refinement of the 1999

guidance (discussed above) EPA

determined additional emission

reductions were needed and the level of

NOx needed for attainment is 305 t/d.

The 230 tons per day emission level

in the May 1998 SIP submission was

based upon "across-the-board" emission

sensitivity modeling and not specific

control measures, as was submitted in

the November 1999 attainment

demonstration. Thus, the 230 tons per

day emission level is not associated

with any control measures, and it is not

appropriate as a regulatory emission

level for an attainment SIP. In addition,

there have been many notable changes

to the modeling emissions inventory

subsequent to the May 1998 SIP

submission. These include revised

biogenic emissions, revised non-road

emissions, and revised 2007 future year

on-road mobile source emissions. Thus,

it is not appropriate to compare the 305

t/d and the 230 t/d, since they are really

based upon different applications of the

model. Further, it is not correct to say

modeling exist that demonstrates how

attainment can be achieved.

With regards to whether the approach

used for the HG area sufficiently

identifies the expected additional

amount of emission reductions needed

for attainment by the deadline, for the

reasons noted above, we believe the

modeling and weight of evidence

techniques used for the HG area do

provide a reasonable estimate of the

emission reductions necessary for

attainment. Furthermore, these emission

reductions are quite substantial. The

projected attainment level of 305 t/d of

NOx is a 71% reduction from the

projected 2007 NOx emissions of 1052

t/d and a 77% reduction from the 1993

NOx emissions of 1337 t/d. This is a

significant amount of NOx reductions

and based on the analyses presented,

EPA believes these level of reductions

will bring the area into attainment.

Comment: A commenter stated that

TNRCC took into account modeling

performance concerns in developing a

weight of evidence analysis to support

its October 1999 SIP revision and

concluded that a modeled control

strategy, nearly identical to the one

described in its December 2000 SIP

revision would produce attainment even

though attainment was not conclusively

demonstrated by the model. EPA

rejected this analysis, however, and

prescribed a new method that the

commenter goes on to criticize.

Response: EPA did not believe that

sufficient emission reductions had been

identified in the control strategy

modeled in the November 1999 episode.

EPA proposed its preliminary analysis

of the November 1999 SIP revision that

a shortfall of 11% NOx emission

reduction existed. Significantly, we

received no comments at the time of

that proposal that the 11% shortfall was

too high. We received comments to the

contrary that the needed additional

emission reductions were understated.

EPA does not agree with the

characterization that EPA "prescribed"

a new method. Other weight of evidence

techniques, as described in EPA

guidance were still available to Texas

and could have been considered. We

worked with Texas in the development

of the quadratic method that was used

as weight of evidence for the HG area to

provide a method that we and Texas

believed gave an accurate estimate of

the needed additional emission

reductions.

Comment: A commenter criticizes

that in contrast to the 1999 Guidance,

the weight of evidence method EPA

developed for the HGA does not employ

a relative reduction factor or a future

design value calculation. The quadratic

extrapolation is neither consistent with

nor an improvement on the 1999

guideline methods and EPA's

description of it as such is erroneous.

The commenter goes on to compare and

contrast specific differences between the

method developed for Houston and the

1999 guidance.

Response: EPA continues to believe,

in the case of the HG area, the method

developed is an improvement over the

November 1999 guidance. This

guidance was developed for estimating

the additional reduction needed to

support the one-hour ozone NAAQS for

those nonattainment areas using a

weight of evidence approach to

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demonstrating attainment. This

guidance describes two methods for

calculating the amount of the additional

reductions needed, but does not

prohibit the use of an alternative

method. Both methods assume that the

relationship between ozone and the

NOx and VOC precursors can be

estimated. Direct application of the two

methods discussed in EPA's November

1999 guidance using available data for

the Houston area, produced a

mathematical impossibility. The results

indicated that all ozone precursor

emissions would have to be reduced to

less than zero. Thus, the two methods

described in the 1999 guidance are not

directly applicable to Houston. EPA and

TNRCC worked together to develop a

revised method that is consistent with

the concepts in the 1999 guidance for

estimating the relationship, but

applicable to the Houston area's

modeling results. The methods in the

guidance use a linear extrapolation of

model results to determine expected

ozone benefits from additional

precursor reductions. The method for

the Houston area is also an

extrapolation of model results. Instead

of a linear extrapolation, however, a

quadratic extrapolation was developed

based on the results of three of the

modeling runs. A quadratic

extrapolation is necessary because of the

non-linearity of the ozone response to

NOx reductions in the Houston area.

Therefore, the method developed for the

HG area is a refinement the two

methods in the 1999 guidance, since

these two methods are also based on

modeling. The factors used in the

method for the Houston area are based on model results for the majority of the

control measures and, consequently, are

scientifically sound for the Houston

area. We believe this approach is

consistent with the intent and criteria of

the 1999 guidance and, in the case of

the Houston area, gives a better

approximation of the amount of

emission reductions that will be

necessary to achieve the standard.

Therefore, this method fulfills the

purposes of the EPA guidance, and it is

as rigorous, if not more rigorous, than

the two methods discussed in the 1999

guidance. Furthermore, it cannot be

accurate to characterize the methods in

the 1999 guidance as better when, in

fact, they produce a mathematical

impossibility for the HG area.

3. Comments on Control Strategies

Comment: One commenter stated that

the plan should provide evidence that

Texas Senate Bill 5 (SB-5) provisions

can be implemented and will lead to at

least 6.7 tons/day of NOx emission

reductions. Another commenter stated

EPA should not give credit to the Texas

Emission Reduction Plan created by SB5 without assurances of long-term

funding levels and details about longterm funding. They also cite information

that the funding for the program might

be less than EPA assumed because of

legal challenges.

Response: Based on experience in

California with the Carl Moyer program,

the Diesel Emission Reduction Program

provided by the Texas Legislature

should be able to provide emissions

reduction in the range of $3000-5000/

ton. This is documented in the report

"The Carl Moyer Memorial Air Quality

Standards Attainment Program (The

Carl Moyer Program) GuidelinesApproved Revision 2000, November 16,

2000 California Environmental

Protection Agency Air Resources

Board." The clear intent of the

legislation, as stated on the TNRCC

website, is "The highest priority for

using the funds under the Emissions

Reduction Grants Program will be to

replace NOx emissions reductions

removed from the State Implementation

Plans (SIPs) for the HG area and Dallas/

Fort Worth (DFW) nonattainment areas

as a result of S.B. 5. Using an average

of $5,000 per ton of NOx reduced, the

TNRCC has determined that it will

require $6.7 million per year in HGA to

replace the construction shift and

accelerated Tier II/III rules. Another

$7.5 million will be required to partially

fill (20 tons) the 56 ton gap, making the

HG area total $14.2 million."

EPA's estimates are not as optimistic

but we do believe the $24.7 million/yr

projected on the TNRCC website should

result in at least 25 tons/year of

emission reductions, an amount

sufficient to offset the construction shift

and accelerated Tier II/III and contribute

to reducing the shortfall. We will work

with Texas to refine the estimates of

emission reductions. It is clear that if

more money is needed for the HG area

as the program is implemented to make

additional reductions in the shortfall,

the TNRCC has the discretion to

channel more money to the Houston

area.

With regard to legal challenges to the

program's funding mechanisms, EPA

will not anticipate a court's findings. If

a court finds the funding mechanism

illegal, Texas will have to revise the SIP

at that time to address the loss in

emission reductions or find alternative

funding sources. In the absence of

timely State action to address any

adverse court ruling, EPA could take

action to ensure attainment is not

jeopardized.

Comment: Commenters questioned

the emissions benefit of the low

emission diesel rule.

Response: The EPA has just

completed a study of the benefits of low

emission diesel fuels, such as the Texas

Clean Diesel fuel. EPA determined the

Texas fuel will result in NOx

reductions. However, it appears that the

NOx reductions based on the justcompleted study will be slightly less

than those projected by Texas. EPA

believes, because the emissions impact

is expected to be small and because

Texas has committed to address any

change to the amount of needed

emission reductions at the mid-course

review, the recent study findings do not

change the approvability of the

attainment demonstration. We will work

with Texas to incorporate the findings

of the study into future SIP revisions.

Comment: One commenter supported

the fact that EPA did not take any action

on morning construction ban.

Response: EPA determined not to take

action on the construction ban since the

legislature had removed the TNRCC's

authority to implement this measure.

Comment: EPA must discount the

emission reduction credit from the

Airport Ground Support Equipment

agreed orders because these orders do

not assign specific budgets to individual

airlines and therefore do not insure the

achievement of any particular ton/day

emissions.

Response: The agreed orders require

percentage reductions from a 1996

baseline which achieve the same

purpose as an emissions limitation. The

reductions specified in each order are

enforceable against the owner/operator

of the equipment, thus providing a

comfortable degree of certainty that the

reductions will take place.

Comment: The EPA should discount

the emission reductions from I/M based

on the recently released National

Research Council (NRC) Report.

Response: The NRC recommendation

provides that the models projecting

emissions from I/M programs should be

improved to reflect actual reductions

more accurately. EPA agrees that

emission performance of vehicles has

improved since the data that form the

basis of existing models were generated.

Most of the data for MOBILE5 was based

on evaluation of early 1980's vehicles.

EPA's soon-to-be-released MOBILE6

model has been substantially updated to

better reflect actual emissions and

actual I/M benefits. The model has also

been made more flexible to better

incorporate local data on compliance,

technician training, and the inclusion/

exclusion of vehicles of certain ages. As

technologies and characteristics of the

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fleet change, data collection, analysis,

and model improvement will likely

continue to be warranted. Texas has

committed to revise the Mobile Vehicle

Emissions Budget using MOBILE6 no

later than 2 years after its official

release. If a transportation conformity

analysis is to be performed between 12

months and 24 months after the

MOBILE6 official release, transportation

conformity will not be determined until

Texas submits an MVEB which is

developed using MOBILE6 and which

we find adequate. Further, it is our

understanding that TNRCC intends to

use Mobile 6 in the attainment

demonstration modeling planned for

submission in December 2002.

Comment: The Act requires the SIP to

include a program to provide for

enforcement of the adopted measures.

Most plans address this requirement,

however, none of the plans clearly set

out programs to provide for

enforcement. Another commenter said

the EPA should take steps to insure

adequate enforcement of permit

standards. Other commenters said the

plan includes unenforceable items such

as the restriction on commercial lawn

mowing.

Response: State enforcement program

elements are contained in SIP revisions

previously approved by EPA under

obligations set out in section 110 of the

Act. Once approved by the EPA, there

is no need for states to readopt and

resubmit their enforcement programs

with each and every SIP revision

generally required by other sections of

the Act.

EPA will monitor the effectiveness of

the new programs, such as the

commercial lawn mowing restriction,

and work with Texas to revise the

programs if necessary.

Comment: The State submittal should

include creditable, adequate rules to

achieve attainment that should also

provide for a margin for error.

Response: EPA generally agrees with

the comment. EPA believes that the

Margin of Error for the HG area plan,

while small, is appropriate in light of

the significant level of reductions in the

plan and the commitment to perform

the mid-course review and to adopt

additional measures as appropriate.

Comment: One commenter stated that

there is over crediting of national rules

for architectural coatings, autorefinishing coatings and consumer

products. They state the credit claimed

is based on EPA estimates of emission

reductions from proposed versions of

these rules, but the final versions of the

rules are weaker than the proposed

rules. Therefore, the credit claimed for

these national rules should be

recalculated to reflect only the actual

emission reductions that can be

expected under the final EPA rules.

Response: Architectural Coatings:

EPA's March 22, 1995 memorandum 8

indicated EPA's view that it was

acceptable for states to claim a 20%

reduction in VOC emissions from the

AIM coatings category in ROP and

attainment demonstration plans based

on the anticipated promulgation of a

national AIM coatings rule. In

developing the attainment SIP for the

Houston area, Texas relied on this

memorandum to estimate emission

reductions from the anticipated national

AIM rule. EPA promulgated the final

AIM rule in September 1998, codified at

40 CFR part 59, subpart D. In the

preamble to EPA's final AIM coatings

regulation, EPA estimated that the

regulation will result in 20% reduction

of nationwide VOC emissions from AIM

coatings categories (63 FR 48855). The

estimated VOC reductions from the final

AIM rule resulted in the same

reductions as those estimated in the

March 1995 EPA policy memorandum.

In accordance with EPA's final

regulation, Texas has assumed a 20%

reduction from AIM coatings source

categories in its attainment modeling.

AIM coatings manufacturers were

required to be in compliance with the

final regulation within one year of

promulgation, except for certain

pesticide formulations which were

given an additional year to comply.

Thus all manufacturers were required to

comply, at the latest, by September

2000. EPA believes that all emission

reductions from the AIM coatings

national regulation will occur by 2002

and therefore are creditable in the

attainment plan for the Houston area.

Autobody Refinish Coatings Rule:

According to EPA's guidance 9 and

proposed national rule, many States

have claimed a 37% reduction from this

source category based on a proposed

rule. However, EPA's final rule,

"National Volatile Organic Compound

Emission Standards for Automobile

Refinish Coatings," published on

September 11, 1998 (63 FR 48806), did

not regulate lacquer topcoats and will

result in a smaller emission reduction of

around 33% overall nationwide. The

8 "Credit for the 15 Percent Rate-of-Progress Plans

for Reductions from the Architectural and

Industrial Maintenance (AIM) Coating Rules,"

March 22, 1995, from John S. Seitz, Director, Office

of Air Quality Planning and Standards to Air

Division Directors, Regions I-X.

9 "Credit for the 15 Percent Rate-of-Progress Plans

for Reductions from the Architectural and

Industrial Maintenance (AIM) Coating Rule and the

Autobody Refinishing Rule," November 27, 1994,

from John S. Seitz, Director, OAQPS, to Air

Division Directors, Regions I-X.

37% emission reduction from EPA's

proposed rule was an estimate of the

total nationwide emission reduction.

Since this number was an overall

average, it was not applicable to any

specific area. For example, in California

the reduction from the national rule is

zero because its rules are more stringent

than the national rule.

Texas did not rely on the above

guidance. Instead, as part of the

development of their 15% Rate of

Progress plan, Texas used data for autorefinishing coating use specific for

Texas to estimate the emission

reductions from existing state rules. To

avoid double counting, for the purposes

of the attainment demonstration, they

did not assume any additional emission

reductions due to the national rule.

Therefore, the Houston area's

attainment demonstration SIP relied on

state rules, not the national rule for its

emission reductions. On EPA's approval

of the 15% ROP plan, EPA approves the

credit Texas is now relying on for

attainment.

Consumer Products Rule: According

to EPA's guidance 10 and proposed

national rule, States have generally

claimed a 20% reduction from this

source category. The final rule,

"National Volatile Organic Compound

Emission Standards for Consumer

Products," (63 FR 48819), published on

September 11, 1998, will result in a

20% reduction. Therefore the

reductions obtained by States from the

final national rule are consistent with

credit which was claimed.

Comment: One commenter included

by reference their comments on the

TNRCC proposed rules. They include

several comments opposing the

Construction Hour shift, Accelerated

Tier I/I1, NOx Reduction Systems (a

requirement to retrofit off-road

equipment), and low sulfur gasoline.

Response: As all of these measures

have been dropped from the State's plan

and were not submitted to EPA. Thus,

no response is necessary.

4. Comments on Enforceable

Commitments

Comment: Several commenters claim

that EPA should not approve the

attainment demonstration for the HG

area because the plan contains, in part,

commitments to adopt measures that are

necessary to reach attainment. The

commenters contend that EPA does not

have authority to accept enforceable

commitments to adopt measures in the

10 "Regulatory Schedule for Consumer and

Commercial Products under Section 183(e) of the

Clean Air Act," June 22, 1995, from John S. Seitz,

Director, OAQPS, to Air Division Directors, Regions

I-X.

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future in lieu of adopted control

measures.

The commenters contend that the 56

tpd gap must be closed now. The

commenters are concerned that Texas

has proposed a process that will take

three more years-until 2004-to

develop and adopt the final control

measures needed for attainment.

Deferred adoption and submittal are not

consistent with the statutory mandates

and are not consistent with the Act's

demand that all SIPs contain

enforceable measures. EPA does not

have authority to approve a SIP if part

of the SIP is not adequate to meet all

tests for approval. Because the submittal

consists in part of commitments, Texas

has not adopted rules implementing

final control strategies, and the plan

includes insufficient reduction

strategies to meet the emission

reduction goals established by the

TNRCC. Thus, Texas has failed to adopt

a SIP with sufficient adopted and

enforceable measures to achieve

attainment. For these reasons, the

submittal also does not meet the NRDC's

consent decree definition of a "full

attainment demonstration SIP," which

obligates EPA to propose a federal

implementation plan if it does not

approve the HG area SIP. For these

reasons, EPA should reject the HG area

SIP and impose sanctions on the area

and publish a proposed FIP no later

than October 15, 2001.

Response: EPA disagrees with the

comments, and believes-consistent

with past practice-that the Act allows

approval of enforceable commitments

that are limited in scope where

circumstances exist that warrant the use

of such commitments in place of

adopted measures."I Once EPA

determines that circumstances warrant

consideration of an enforceable

commitment, EPA believes that three

factors should be considered in

determining whether to approve the

enforceable commitment: (1) Whether

11 These commitments are enforcd by the EPA

and citizens under, repesetively, sections 113 adn

301 of the Act. In the past, EPA has approved

enforceable commitments and courts have enforced

these actions against states that failed to comply

with those commitments. See, e.g., American Lung

Association of New Jersey v. Kean, 670 F. Supp.

1285 (D.N.J 1987), affirmed, 871 F.2d 319 (3rd Cih.

1989); NRDC v. N.Y. State Dept. of Environmental

Conservation, 668 F. Supp. 848 (S.D.N.Y. 1987);

Citizens for a Better Environment v. Deukmejian,

731 F. Supp. 1448, reconsideration granted in part,

746 F. Supp. 976 (N.D. Cal. 1990); Coalition for

Clean Air, et al. v. South Coast Air Quality

Management District, CARB and EPA, No. CV 97-

6916 HLH, (C.D. Cal. August 27, 1999). Further, if

a state fails to meet its commitments, EPA could

make a finding of failure to implement the SIP

under Section 179(a), which would start an 18-

month period for the State to begin implementation

before mandatory sactions are imposed.

the commitment addresses a limited

portion of the statutorily-required

program; (2) whether the state is capable

of fulfilling its commitment; and (3)

whether the commitment is for a

reasonable and appropriate period of

time.

As an initial matter, EPA believes that

present circumstances for the New York

City, Philadelphia, Baltimore and

Houston nonattainment areas warrant

the consideration of enforceable

commitments. The Northeast states that

make up the New York, Baltimore, and

Philadelphia nonattainment areas

submitted SIPs that they reasonably

believed demonstrated attainment with

fully adopted measures. After EPA's

initial review of the plans, EPA

recommended to these areas that

additional controls would be necessary

to ensure attainment. Because these

areas had already submitted plans with

many fully adopted rules and the

adoption of additional rules would take

some time, EPA believed it was

appropriate to allow these areas to

supplement their plans with enforceable

commitments to adopt and submit

control measures to achieve the

additional necessary reductions. For the

HG area, the State has submitted

supporting information that EPA has

confirmed indicating that Texas has

adopted for the HG area NOx controls

that are as tight or tighter than any other

area including the one extreme areaSouth Coast. Thus, because the State has

adopted many strict controls that were

included in the submitted plan and

needs additional time to consider

technologies that are still in the

developmental stages, EPA determined

that it is appropriate to consider an

enforceable commitment for the

remaining necessary reductions. For the

HG area, EPA has determined that the

submission of enforceable commitments

in place of adopted control measures for

this limited set of reductions will not

interfere with the area's ability to meet

its rate-of-progress obligations.

EPA's approach here of considering

enforceable commitments that are

limited in scope is not new. EPA has

historically recognized that under

certain circumstances, issuing full

approval may be appropriate for a

submission that consists, in part, of an

enforceable commitment. See e.g., 62 FR

1150, 1187 (Jan. 8, 1997) (ozone

attainment demonstration for the South

Coast Air Basin); 65 FR 18903 (Apr. 10,

2000) (revisions to attainment

demonstration for the South Coast Air

Basin); 63 FR 41326 (Aug. 3, 1998)

(federal implementation plan for PM-10

for Phoenix); 48 FR 51472 (State

Implementation Plan for New Jersey).

Nothing in the Act speaks directly to the

approvability of enforceable

commitments.12 However, EPA believes

that its interpretation is consistent with

provisions of the Act. For example,

section 110(a)(2)(A) provides that each

SIP "shall include enforceable emission

limitations and other control measures,

means or techniques * * * as well as

schedules and timetables for

compliance, as may be necessary or

appropriate to met the applicable

requirement of the Act." Section

172(c)(6) of the Act requires, as a rule

generally applicable to nonattainment

SIPs, that the SIP "include enforceable

emission limitations and such other

control measures, means or techniques

* * * as may be necessary or

appropriate to provide for attainment • * * by the applicable attainment date

... " (Emphasis added.) The

emphasized terms mean that

enforceable emission limitations and

other control measures do not

necessarily need to generate reductions

in the full amount needed to attain.

Rather, the emissions limitations and

other control measures may be

supplemented with other SIP rules-for

example, the enforceable commitments

EPA is approving today-as long as the

entire package of measures and rules

provides for attainment. EPA's

interpretation that the Act allows for a

approval of limited enforceable

commitments has been upheld by the

courts of appeals in some circuits. See

City of Seabrookv. EPA, 659 F.2d 1349

(5th Cir. 1981); Connecticut Fund for the

Environment v. EPA, 672 F.2d 998 (2d

Cir.), cert. denied 459 U.S. 1035 (1982);

Friends of the Earth v. EPA, 499 F.2d

1118 (2d Cir. 1974); Kamp v.

Hernandez, 752 F.2d 1444 (9th Cir.

1985).

As provided above, after concluding

that the circumstances warrant

consideration of an enforceable

commitment-as they do for the HG

area-EPA would consider three factors

in determining whether to approve the

submitted commitments. First, EPA

believes that the commitments must be

limited in scope. In 1994, in considering

EPA's authority under section 110(k)(4)

to conditionally approve unenforceable

commitments, the Court of Appeals for

the District of Columbia Circuit struck

down an EPA policy that would allow

12 Section 110(k)(4) provides for "conditional

approval" of commitments that need not be

enforceable. Under that section, a State may commit

to "adopt specific enforceable measures" within

one-year of the conditional approval. Rather than

enforcing such commitments against the State, the

Act provides that the conditional approval will

convert to a disapproval if "the State fails to comply

with such commitment."

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States to submit (under limited

circumstances) commitments for entire

programs. Natural Resources Defense

Councilv. EPA, 22 F.3d 1125 (D.C. Cir.

1994). While EPA does not believe that

case is directly applicable here, EPA

agrees with the Court that other

provisions in the Act contemplate that

a SIP submission will consist of more

than a mere commitment. See NRDC,

22. F.3d at 1134.

In the present circumstances, the

commitments address only a small

portion of the plan. For the HG area, the

commitment addresses only 6% of the

emission reductions necessary to attain

the standard. Already adopted measures

include controls to reduce NOx

emissions by approximately 90% from

industrial sources, a more stringent and

expanded I/M program, a Clean Diesel

Program, a well-funded incentive

program to encourage the early

introduction of cleaner diesel

equipment, controls on airport ground

support equipment, and several

voluntary measures to reduce emissions

from mobile sources.

As to the second factor, whether the

State is capable of fulfilling the

commitment, EPA considered the

current or potential availability of

measures capable of achieving the

additional level of reductions

represented by the commitment and

whether the State has or is capable of

getting the requisite authority to adopt

measures to achieve those reductions.

For HG area, the SIP submittal already

includes substantial reductions,

covering every significant NOx source

category. The SIP for the HG area

already includes NOx control

requirements that, overall, are more

expensive and technologically

advanced, and apply to smaller emitters,

than those in any other SIP in the nation

other than the South Coast-the one

area classified as extreme for the 1-hour

ozone standard. Thus, determining

measures that will generate the

necessary additional reductions is

significantly more complex than for the

northeastern States. However, the State

has provided EPA with sufficient

information to assure EPA that it will be

capable of adopting controls to achieve

the necessary level of emission

reductions. First, the State has

identified advanced technologies and

innovative ideas that, in EPA's opinion,

are or will be shortly available and thus

could be adopted and implemented in

sufficient time for the HG area to attain

by 2007. Furthermore, the State has

identified a range of emission

reductions that potentially could be

achieved by each of these advanced

technologies and innovative strategies.

While at this time the State-in

conjunction with EPA-is still working

to assess the appropriate level of

reductions that may be achieved by

these technologies and strategies, EPA

believes that the totality of the current

information is sufficient to assure EPA

that Texas can meet its commitment to

adopt measures that will achieve the

level of reductions necessary to meet the

HG area's shortfall.

The third factor, EPA has considered

in determining to approve limited

commitments for the HG area

attainment demonstration is whether

the commitment is for a reasonable and

appropriate period. EPA recognizes that

both the Act and EPA have historically

emphasized the need for submission of

adopted control measures in order to

ensure expeditious implementation and

achievement of required emissions

reductions. Thus, to the extent that

other factors-such as the need to

consider innovative control strategiessupport the consideration of an

enforceable commitment in place of

adopted control measures, the

commitment should provide for the

adoption of the necessary control

measures on an expeditious, yet

practicable, schedule.

Texas is faced with exploring cuttingedge technology, as it has already

required extremely stringent controls.

Thus, in considering the appropriate

amount of time for Texas to meet its

commitment, EPA considered that

Texas needs time to develop and assess

the capabilities of these technologies in

addition to the time it needs to adopt

the measures that will achieve the

needed level of emission reductions.

Because some of the measures that

Texas is considering are further along in

the development process, Texas has

committed to adopt measures to fill a

portion of the shortfall in the near term

and to adopt the remaining measures by

an intermediate-term date. Thus, Texas

has committed to adopt controls to

achieve 25% of the needed emission

reductions by December 2002 and to

adopt controls to achieve the remaining

level of reduction by May 1, 2004. EPA

believes that this schedule is

expeditious in light of the types of

cutting-edge controls that Texas needs

to evaluate, develop and then adopt in

order to achieve the level of reductions

needed in the HG area. In addition, EPA

believes that these adoption dates will

not impede Houston's ability to attain

the 1-hour ozone standard by November

15, 2007 nor will it impede Houston's

ability to meet the ROP requirement

because the HG area can meet the ROP

requirement with already adopted

measures.

The enforceable commitments

submitted for the HG nonattainment

area, in conjunction with the other SIP

measures and other sources of emissions

reductions, constitute the required

demonstration of attainment and the

commitments will not interfere with the

area's ability to make reasonable

progress under section 182(c)(2)(B) and

(d). EPA believes that the delay in

submittal of the final rules is

permissible under section 110(k)(3)

because the State has obligated itself to

submit the rules by specified short-term

and intermediate-term dates, and that

obligation is enforceable by EPA and the

public. Moreover, as discussed in the

proposal and TSD, the SIP submittal

approved today contains major

substantive components submitted as

adopted regulations and enforceable

orders.

EPA does not agree with the assertion

that the HG area SIP does not meet the

NRDC consent decree definition of a

"full attainment demonstration." The

consent decree defines a "full

attainment demonstration" as a

demonstration according to CAA section

182(c)(2). As a whole, the attainment

demonstration-consisting of

photochemical grid modeling, adopted

control measures, an enforceable

commitment with respect to a limited

portion of the reductions necessary to

attain, and other analyses and

documentation-is approvable since it

"provides for attainment of the ozone

(NAAQS) by the applicable attainment

date." See section 182(c)(2)(A).

Comment: The SIP includes explicit

enforceable commitments to consider

relaxing regulations on industrial point

sources. EPA must reject any efforts to

relax effective control measures on the

books before the TNRCC eliminates the

identified shortfall in emission

reductions. Proposed changes to the

plan would commit the TNRCC to

consider steps that will unlawfully

increase the gap between predicted

emission reductions resulting from

regulatory measures and the emission

reduction goals established by the

TNRCC. Further, it is unlawful for the

SIP to contain a promise to relax NOx

point sources in exchange for

implementation of measures to control

upset emissions.

Response: The TNRCC has included

in Chapter 7 of the SIP its commitment

to developing an enforceable plan to

reduce releases of reactive hydrocarbon

emissions and emissions of chlorine.

Recent findings from the Texas 2000 Air

Quality Study indicate that highly

reactive hydrocarbons and/or chlorine

emissions may be primary causes of the

rapid build-up of ozone in the HG area.

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TNRCC goes on to say that to the extent

that the science confirms the benefit

from this program then it is the intent

of the commission to implement such a

program through a SIP revision which

would also decrease NOx reductions

required from industrial sources down

to 80% control. At this time, EPA is not

acting on whether this potential, future

SIP revision would be approvable. At

this time, we are considering only the

effective State rules before us that

include 90% control on industrial

source NOx emissions. The State's

commitment to consider alternative

control strategies in the future has no

bearing on this approval. The Supreme

Court has consistently held that under

the Act, initial and primary

responsibility for deciding what

emissions reductions will be required

from which sources is left to the

discretion of the States. Whitman v. Am.

TmckingAss'ns, 531 U.S. 457 (2001);

Train v. NRDC, 421 U.S. 60 (1975). This

discretion includes the continuing

authority to revise choices about the

mix of emission limitations. Train at 79.

Therefore, EPA believes that it is

appropriate and authorized under the

Act for a State to continue to update its

growth projections, inventories,

modeling analyses, control strategies,

etc., and submit these updates as a SIP

revision based on newly available

science and technology.

However, section 110(1) of the Act

governs EPA's review of a SIP revision

from a state that wishes to make changes

to its approved SIP. This section

provides that EPA may not approve a

SIP revision if it will interfere with any

applicable requirement concerning

attainment and reasonable further

progress or any other applicable

requirement of the Act.' 3 Therefore, if

we receive an attainment demonstration

SIP revision from Texas that contains

relaxed control measures or the

replacement of existing control

measures, we would consider the

revised plan's prospects for meeting the

current attainment requirements and

other applicable requirements of the

Act. See, the Act section 110(k)(3),

Union Electric v. EPA, 427 U.S. 246

(1976) and Train, 421 U.S. at 79.

In summary, the State may choose to

submit a SIP revision in 2002 or 2003

as it has suggested it may do. If we

receive a SIP revision that meets our

completeness criteria, we will review it

13 The Supreme Court under the 1970 CAA,

observed that EPA's judgment in determining the

approval of a SIP revision is to "measure the

existing level of pollution, compare it with the

national standards, and determine the effect on this

comparison of specified emission modifications."

Train at 93.

against the statutory requirements of

section 110(1). Further, the Act requires

us to publish a notice and to provide for

public comment on our proposed

decision. EPA believes that it is in the

context of that future rulemaking, not

EPA's current approval, that the

commenter's concern regarding the

appropriateness of any replacement

measures adopted by the State should

be considered.

Comment: The mid-course review

process outlined by TNRCC is not a

permissible substitute for a currently

complete attainment demonstration or

adopted enforceable control measures.

The mid-course review will delay final

approval of the SIP until 2004, 10 years

after the SIP was required under the

Act.

Response: The mid-course review is

not intended as a replacement for a

complete attainment demonstration or

as a replacement for adopted control

measures. As provided elsewhere in the

responses to comments, EPA believes

the State's commitment to adopt

additional measures is appropriate. It is

intended to reflect the reality that the

modeling techniques and inputs are

uncertain. Thus, the progress of

implementing the plan should be

evaluated so that adjustments can be

made to ensure the plan is successful.

EPA is fully approving the attainment

demonstration based on the information

currently available. The mid-course

review allows the State and EPA an

opportunity to consider additional

information closer to the attainment

date to assess whether adjustments are

necessary.

In the case of Texas, the State has

extensive plans to fully evaluate the

inputs to the model and the modeling

itself using the most up to date

information possible. The State will also

be evaluating several new control

measures for inclusion in the SIP. We

are fully supportive of this continued

evaluation of the science supporting the

plan to reach attainment.

Comment: TNRCC has failed to meet

its commitment to provide a plan by

July 8, 2001. The TNRCC has reneged on

previous commitments to model

attainment. These demonstrate reasons

for our objection to EPA's reliance on

commitments.

Response: We do not agree that

TNRCC has reneged on previous

commitments to model attainment. As

discussed in the response to comments

on modeling, using weight of evidence

in conjunction with the model is an

appropriate method of demonstrating

attainment. Further, Texas has made

every effort to adopt all of the necessary

measures to demonstrate attainment.

Therefore, as discussed previously, EPA

believes that it is acceptable to allow

additional time for the development of

new programs or measures for a small

percentage of the needed reductions.

Comment: Texas provided a comment

letter on EPA's December 1999

proposal. In this letter, Texas explained

their plans to provide the following

elements and enforceable commitments

by April 2000: (1) A list of measures that

could be used to achieve attainment (2)

a commitment to provide a new mobile

source emissions budget using

MOBILE6 by May 2004, (3) a

reenforcement of their previous

commitment to adopt the majority of

necessary rules for attainment by

December 31, 2000, and to adopt the

remainder if necessary by July 31, 2001,

and (4) a commitment to perform a midcourse review.

Response: TNRCC adopted these

elements in April 2000. We are now

approving the commitments that are

still relevant. (See the final action

section).

Comment: One commenter suggested

several specific language changes to the

enforceable commitments in the Texas

SIP.

Response: EPA and TNRCC met and

agreed that some but not all of the

language changes should be made. The

section on changes from the proposal

explain these changes. Other specific

language changes proposed by the

commenters are not necessary for

approvable enforceable commitments.

5. Comments on Motor Vehicle

Emissions Budgets

a. Comments on the July 12, 2001

Proposal

Comment: The commenters raised

several questions concerning the Motor

Vehicle Emissions Budgets (the budgets)

established in the Houston attainment

demonstration SIP. The commenters

stated that the budgets submitted in the

SIP should not be called adequate or be

approved by the EPA because the

attainment demonstration SIP does not

provide for attainment. One commenter

specifically pointed to the need for

adopted and enforceable control

measures.

Response: The rate-of-progress (ROP)

budgets for the year of 2007 are 79.5 tpd

and 156.7 tpd for VOC and NOx,

respectively. The commenters support

these budgets. In addition, these budgets

are identified as the budgets for the

2007 attainment demonstration SIP

which are being approved by the EPA

only until revised budgets pursuant to

the State's commitments relating to

MOBILE6 and shortfall measures are

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submitted and we have found them

adequate for transportation conformity

purposes. Approval of the attainment

budgets is based on the current control

measures specified in the SIP and the

enforceable commitments made for

additional controls which will be

implemented in the interim period.

Because all measures which have not

yet been adopted are included in

written commitments in the SIP, EPA

believes that it can find the budgets

adequate. The EPA believes that

consistency of the budgets related to the

emissions inventory, and SIP control

strategy are demonstrated and meet the

requirements of 40 CFR 93.118(e).

Therefore, the budgets for the

attainment demonstration SIP are

adequate for transportation conformity

purposes. Also, it should be noted that

the conformity rules allow emission

reduction credit to be taken for purposes

of conformity determinations for any

measures that have been either adopted

by the enforcing jurisdiction, included

in the applicable implementation plan,

contained in a written commitment in

the submitted implementation plan, or

promulgated by EPA as a federal

measure. See 40 CFR 93.122(a)(3).

As described in the November 3, 1999

memorandum entitled "Guidance on

Motor Vehicle Emissions Budgets in

One-Hour Ozone Attainment

Demonstrations," from Marylin ZawMon, Office of Mobile Sources, to Air

Division Directors, Regions I-VI, there

are circumstances in which the EPA

could find a SIP's motor vehicle

emissions budgets adequate even

though additional emission reductions

are necessary in order to demonstrate

attainment. Specifically, the EPA's

position is that the motor vehicle

emissions budgets could be adequate for

conformity purposes if the State

commits to adopt, for the area, measures

that will achieve the necessary

additional reductions, and the State

identifies a menu of possible measures

that could achieve the reductions

without requiring additional limits on

highway construction. The HG area's

SIP contains such commitments and

such a menu.

We believe that the budgets can be

found adequate and approvable because

the budgets will not interfere with the

area's ability to adopt additional

measures to attain the ozone standard

and they are consistent with the

attainment demonstration SIP. While

the area is adopting its additional

measures, the SIP's budgets will cap

motor vehicle emissions and thereby

ensure that the amount of additional

reductions necessary to demonstrate

attainment will not increase. The

budgets are consistent with and clearly

related to the emissions inventory and

the control measures and consistent

with attainment. EPA disagrees that the

SIP does not provide for attainment. For

further explanation of how this

attainment demonstration SIP as an

overall plan provides for attainment

please see other responses directly

relating to the sufficiency of the overall

attainment plan, control strategy,

enforceable commitments, etc.

contained in this final action.

Comment: The commenters asserted

that further NOx reductions needed for

attainment will require additional onroad mobile source controls and these

controls will result in a lower motor

vehicle emissions budget. The

commenters felt that the budgets

established in the SIP are too high and

the NOx budgets should be reduced by

30 or more tpd.

Response: Agency policy for the areas

needing additional emission reductions

has provided that, in certain cases, EPA

may determine the budget adequate

even when the SIP includes

commitments to additional measures. In

a November 3, 1999, Memorandum

entitled "Guidance on Motor Vehicle

Emissions Budgets in One-Hour Ozone

Attainment Demonstrations," EPA

issued guidance regarding such

commitments in the ozone attainment

demonstrations for the HG area as well

as other areas. We indicated that

budgets could be based on potential

control measures identified in the SIP

that, when implemented, would be

expected to achieve the emission

reductions necessary for attainment of

the standard and a commitment to adopt

measures to achieve the reductions.

These measures may not involve

additional limits on highway

construction beyond the restrictions

already imposed under the submitted

motor vehicle emissions budget. As long

as the additional measures do not

involve additional limits on highway

construction, allowing new

transportation investments consistent

with the submitted budgets will not

prevent the area from achieving the

additional reductions that it needs for

attainment. This allows the EPA to

consider the budgets adequate for

transportation conformity purposes. The

HG area SIP contains such commitments

and measures. The SIP demonstrates

that the budgets will not interfere with

the HG area's ability to adopt additional

measures to attain.

The budgets established in the SIP are

consistent with the process in 40 CFR

93.118(e), and the EPA does not

consider them too high within the

context of the ozone attainment

demonstration SIP as described above

and further documented in the SIP and

EPA's TSD. The budgets are consistent

with and clearly related to the emissions

inventory and the control measures and

consistent with attainment. Our

approval of the budgets is limited until

revised budgets are submitted and we

have found them adequate for

transportation conformity purposes.

Texas has committed to revise the

budgets relating to MOBILE6 and the

shortfall measures. While the list of

potential measures does include

measures that pertain to motor vehicles,

none of the measures involves

additional limits on highway

construction; therefore, if lower budgets

do result, the transportation investments

will still be consistent with the budgets

and will not prevent the HG area from

achieving attainment.

Comment: The motor vehicle

emissions budgets are inadequate

because they do not provide for all

reasonably available control measures to

attain the standard as expeditiously as

practicable.

Response: The motor vehicle

emissions budgets are adequate. The SIP

includes all necessary RACM and

provides for expeditious attainment as

explained further in the RACM section

of this action.

b. Comments on July 28, 2001

Supplemental Notice

Comment: One commenter generally

supports a policy of requiring motor

vehicle emissions budgets to be

recalculated when revised MOBILE

models are released.

Response: The Phase II attainment

demonstrations that rely on Tier 2

emission reduction credit contain

commitments to revise the motor

vehicle emissions budgets after

MOBILE6 is released.

Comment: The revised budgets

calculated using MOBILE6 will likely be

submitted after the MOBILE5 budgets

have already been approved. EPA's

policy is that submitted SIPs may not

replace approved SIPs.

Response: This is the reason that EPA

proposed in its July 28, 2000

Supplemental Notice of Proposed

Rulemaking (65 FR 46383) that the

approval of the MOBILE5 budgets for

conformity purposes would last only

until MOBILE6 budgets had been

submitted and found adequate. In this

way, the MOBILE6 budgets can apply

for conformity purposes as soon as they

are found adequate.

Comment: If a State submits

additional control measures that affect

the motor vehicle emissions budgets but

does not submit revised motor vehicle

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emissions budgets, EPA should not

approve the attainment demonstration.

Response: EPA agrees. The motor

vehicle emissions budgets in the HG

area attainment demonstration reflect

the motor vehicle control measures in

the attainment demonstration. In

addition, Texas would be required to

submit a new budget if any adopted

measures would change the budget, and

Texas has committed to submit a new

budget if they adopt additional control

measures that reduce on-road vehicle

emissions.

Comment: EPA should make it clear

that the motor vehicle emissions

budgets to be used for conformity

purposes will be determined from the

total motor vehicle emissions reductions

required in the SIP, even if the SIP does

not explicitly quantify a revised motor

vehicle emissions budget.

Response: EPA will not approve SIPs

without motor vehicle emissions

budgets that are explicitly quantified for

conformity purposes. The HG

attainment demonstration contains

explicitly quantified motor vehicle

emissions budgets which EPA has found

adequate and approvable.

Comment: If a state fails to follow

through on its commitment to submit

the revised motor vehicle emissions

budgets using MOBILE6, EPA could

make a finding of failure to submit a

portion of a SIP, which would trigger a

sanctions clock under section 179.

Response: If a state fails to meet its

commitment, EPA could make a finding

of failure to implement the SIP, which

would start a sanctions clock under

section 179 of the Act.

Comment: If the budgets recalculated

using MOBILE6 are larger than the

MOBILE5 budgets, then attainment

should be demonstrated again.

Response: As EPA proposed in its

December 16, 1999 notices, we will

work with States on a case-by-case basis

if the new emissions estimates raise

issues about the sufficiency of the

attainment demonstration.

Comment: If the MOBILE6 budgets are

smaller than the MOBILE5 budgets, the

difference between the budgets should

not be available for reallocation to other

sources unless air quality data show that

the area is attaining, and a revised

attainment demonstration is submitted

that demonstrates that the increased

emissions are consistent with

attainment and maintenance. Similarly,

the MOBILE5 budgets should not be

retained (while MOBILE6 is being used

for conformity demonstrations) unless

the above conditions are met.

Response: EPA agrees that if

recalculation using MOBILE6 shows

lower motor vehicle emissions than

MOBILE5, then these motor vehicle

emission reductions cannot be

reallocated to other sources or assigned

to the motor vehicle emissions budget

unless the area reassesses the analysis in

its attainment demonstration and shows

that it will still attain. In other words,

the area must assess how its original

attainment demonstration is impacted

by using MOBILE6 vs. MOBILE5 before

it reallocates any apparent motor

vehicle emission reductions resulting

from the use of MOBILE6. In addition,

Texas will be submitting new budgets

based on MOBILE6 so the MOBILE5

budgets will not be retained in the SIP

indefinitely.

Comment: We received a comment on

whether the grace period before

MOBILE6 is required in conformity

determinations will be consistent with

the schedules for revising SIP motor

vehicle emissions budgets ("budgets")

within 1 or 2 years of MOBILE6's

release.

Response: This comment is not

germane to this rulemaking, since the

MOBILE6 grace period for conformity

determinations is not explicitly tied to

EPA's SIP policy and approvals.

However, EPA understands that a longer

grace period would allow some areas to

better transition to new MOBILE6

budgets. EPA is considering the

maximum 2-year grace period allowed

by the conformity rule, and EPA will

address this in the future when the final

MOBILE6 emissions model and policy

guidance is released.

Comment: One commenter asked EPA

to clarify in the final rule whether

MOBILE6 will be required for

conformity determinations once new

MOBILE6 budgets are submitted and

found adequate.

Response: This comment is not

germane to this rulemaking. However, it

is important to note that EPA intends to

clarify its policy for implementing

MOBILE6 in conformity determinations

when the final MOBILE6 model is

released. EPA believes that MOBILE6

should be used in conformity

determinations once new MOBILE6

budgets are found adequate.

Comment: One commenter did not

prefer the additional option for a second

year before the state has to revise the

conformity budgets with MOBILE6,

since new conformity determinations

and new transportation projects could

be delayed in the second year.

Response: EPA proposed the

additional option to provide further

flexibility in managing MOBILE6 budget

revisions. The supplemental proposal

did not change the original option to

revise budgets within one year of

MOBILE6's release. State and local

governments can continue to use the 1-

year option, if desired, or submit a new

commitment consistent with the

alternative 2-year option. EPA expects

that state and local agencies have

consulted on which option is

appropriate and have considered the

impact on future conformity

determinations. Texas has committed to

revise its budgets within 2 years of

MOBILE6's release for the HG area.

Texas has committed that if a

transportation conformity analysis is to

be performed between 12 months and

24 months after the MOBILE6 official

release, transportation conformity will

not be determined until Texas submits

an MVEB which is developed using

MOBILE6 and which we find adequate.

6. Comments on RACM

a. Comments on December 16, 1999

Proposal

Comment: Several commenters stated

in response to the December 16, 1999

proposed approval/proposed

disapprovals for the severe areas and

certain serious areas that there is no

evidence in several states that they have

adopted reasonably available control

measures (RACM) or that the SIPs have

provided for attainment as

expeditiously as practicable.

Specifically, the lack of Transportation

Control Measures (TCMs) was cited in

several comments, but potential

stationary source controls were also

covered. One commenter stated that

mobile source emission budgets in the

plans are by definition inadequate

because the SIPs do not demonstrate

timely attainment or contain the

emissions reductions required for all

RACM. That commenter claims that

EPA may not find adequate a motor

vehicle emission budget (MVEB) that is

derived from a SIP that is inadequate for

the purpose for which it is submitted.

The commenter alleges that none of the

MVEBs submitted by the states that EPA

is considering for adequacy is consistent

with either the level of emissions

achieved by implementation of all

RACM nor are they derived from SIPs

that provide for attainment. Some

commenters stated that for measures

that are not adopted into the SIP, the

State must provide a justification why

they were determined to not be RACM.

Response: The EPA reviewed the

November 1999 submission for the HG

area and determined that it did not

include sufficient documentation

concerning available RACM measures.

For all of the severe areas for which EPA

proposed approval in December 1999,

EPA consequently issued policy

guidance memorandum to have these

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States address the RACM requirement

through an additional SIP submital.

(Memorandum of December 14, 2000,

from John S. Seitz, Director, Office of

Air Quality Planning and Standards, re:

"Additional Submission on RACM from

States with Severe 1-hour Ozone

Nonattainment Area SIPs."

On May 30, 2001, TNRCC proposed a

RACM analysis which we proposed to

approve on July 13, 2001 through

parallel processing. The State finalized

its RACM analysis on September 26,

2001. The Governor submitted this final

RACM analysis in a letter dated October

4, 2001. Based on this SIP supplement,

EPA concluded that the SIP for the HG

area meets the requirement for adopting

RACM.

Section 172(c)(1) of the Act requires

SIPs to contain RACM and provides for

areas to attain as expeditiously as

practicable. EPA has previously

provided guidance interpreting the

requirements of 172(c)(1). See 57 FR

13498, 13560 (April 16, 1992). In that

guidance, EPA indicated its

interpretation that potentially available

measures that would not advance the

attainment date for an area would not be

considered RACM. EPA also indicated

in that guidance that states should

consider all potentially available

measures to determine whether they

were reasonably available for

implementation in the area, and

whether they would advance the

attainment date. Further, states should

indicate in their SIP submittals whether

measures considered were reasonably

available or not, and if measures are

reasonably available they must be

adopted as RACM. Finally, EPA

indicated that states could reject

measures as not being RACM because

they would not advance the attainment

date, would cause substantial

widespread and long-term adverse

impacts, would be economically or

technologically infeasible, or would be

unavailable based on local

considerations, including costs. The

EPA also issued a recent memorandum

re-confirming the principles in the

earlier guidance, entitled, "Guidance on

the Reasonably Available Control

Measures (RACM) Requirement and

Attainment Demonstration Submissions

for Ozone Nonattainment Areas." John

S. Seitz, Director, Office of Air Quality

Planning and Standards. November 30,

1999. Web site: http://www.epa.gov/ttnl

oarpg/tlpgm.html.

EPA evaluated the Texas RACM

demonstration and performed an

additional analysis of TCMs as

described in the TSD for the July 12,

2001 proposed approval. Specific

comments on the RACM demonstration

are addressed in later responses to

comments.

Although EPA does not believe that

section 172(c)(1) requires

implementation of additional measures

for the HG area, this conclusion is not

necessarily valid for other areas. Thus,

a determination of RACM is necessary

on a case-by-case basis and will depend

on the circumstances for the individual

area. 14 In addition, if in the future EPA

moves forward to implement another

ozone standard, this RACM analysis

would not control what is RACM for

these or any other areas for that other

ozone standard.

Also, EPA has long advocated that

States consider the kinds of control

measures that the commenters have

suggested, and EPA has indeed

provided guidance on those measures.

See, e.g., http://www.epa.gov/otaql

transp.htm. In order to demonstrate that

they will attain the 1-hour ozone

NAAQS as expeditiously as practicable,

some areas may need to consider and

adopt a number of measures-including

the kind that Texas itself evaluated in

its RACM analysis-that even

collectively do not result in many

emission reductions. Furthermore, EPA

encourages areas to implement

technically available and economically

feasible measures to achieve emissions

reductions in the short term-even if

such measures do not advance the

attainment date-since such measures

will likely improve air quality. Also,

over time, emission control measures

that may not be RACM now for an area

may ultimately become feasible for the

same area due to advances in control

technology or more cost-effective

implementation techniques. Thus, areas

should continue to assess the state of

control technology as they make

progress toward attainment and

consider new control technologies that

may in fact result in more expeditious

improvement in air quality. The mid

course review process outlined by Texas

in Chapter 7 of the SIP contains the

State's commitment to continue to

evaluate new technologies as potentially

RACM, for inclusion later in the plan.

The TNRCC adopted an enforceable

commitment to submit a revised SIP no

later than May 1, 2004, addressing any

new information including an "ongoing

assessment of new technologies and

innovative ideas to incorporate into the

plan."

Because EPA is finding that the SIP

meets the Clean Air Act's requirement

14 See, Oberv. EPA, 84 F.3d 304, 311 (9th cir.

1996) (citing the General Preamble, 57 Fed.Reg. at

13560 (April 16, 1992) which held that EPA did not

abuse discretion when changing the interpretation

of the RACM provisions of the Act.

for RACM and that there are no

additional reasonably available control

measures that can advance the

attainment date, EPA concludes that the

attainment date being approved is as

expeditiously as practicable

EPA previously responded to

comments concerning the adequacy of

the MVEBs submitted with the

November 1999 SIP submission when

EPA took final action determining the

budgets (associated with that 1999 plan)

adequate and does not address those

issues again here. The responses are

found at http://www.epa.gov/omsl

transp/conform/pastsips.htm. It should

be noted, since that time, EPA has found

the MVEBs in the November 1999 HG

attainment demonstration SIP

inadequate. (66 FR 35420, July 5, 2001)

We are now approving and finding

adequate through parallel processing the

budgets finally submitted by Texas in a

letter dated October 4, 2001. The section

of this notice on MVEBs explains why

the budgets are adequate and indicates

that the budgets are consistent with the

conclusion that the SIP contains all

necessary RACM for expeditious

attainment.

b. Comments on July 12, 2001 Proposal

Comment: EPA cannot invent

rationales for the states: EPA concedes

that Texas failed to adequately justify

rejection of RACMs identified as

measures to be considered in the future,

or provides its own rationales for why

Texas might have rejected other RACMs

not included on the list to be considered

in the future. The Act and EPA guidance

require the State to perform the required

RACM analysis. EPA's role is limited to

reviewing what the states have

submitted, and approving or

disapproving it. 42 U.S.C. 7410(k)(3);

Riverside Cement Co. v. Thomas, 843

F.2d 1246 (9th Cir. 1988). EPA "may

either accept or reject what the state

proposes; but EPA may not take a

portion of what the state proposes and

amend the proposal ad libitum." Id. If

states are going to reject control

measures, their decision to do so and

the rationale therefore must be subject

to notice and hearing at the state and

local level. This comment is essentially

the same as a comment provided on

EPA's October 12, 2000 Notice of

Availability proposing action regarding

RACM for the three serious areas of

Atlanta, Washington DC and

Springfield, MA.

Response: In the case of the HG SIP,

Texas has performed an analysis of

whether all RACM were included in the

SIP. Based upon its analysis, the State

concluded that one additional measure

not included in the December 2000 SIP

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submission, control of small liquid fired

engines, was reasonably available and

therefore proposed and adopted a rule

to control these sources. Otherwise, the

State concluded all RACM were in

place. The public did have a chance to

comment at the State level on the State's

conclusion that no additional RACM

were required. The EPA believes that

the State analysis was adequate. We

reviewed the State's proposed analysis

and discussed our evaluation of it in the

TSD for our July 2001 proposed action

on the State's RACM analysis. The EPA

did not amend the SIP; EPA evaluated

the State's analysis and for

transportation control measures,

supplemented the State's rationale with

additional thoughts on why we believed

the RACM analysis was adequate. We

explain in the TSD why we agree with

the State that no additional measures

are RACM for the HG area and therefore

the RACM requirement of the Act is

met.

The commenter cites Riverside

Cement for the proposition that EPA

cannot perform an analysis of whether

the State's plan complies with the Act's

RACM requirement. The EPA believes

that the holding of that case is

inapplicable to these facts. In Riverside

Cement, EPA approved a control

requirement establishing an emission

limit into the SIP and disregarded a

contemporaneously-submitted

contingency that would allow the State

to modify the emission limit. Thus, the

court concluded that EPA "amended"

the State proposal by approving into the

SIP something different than what the

State had intended. 843 F.2d at 1248. In

the present circumstances, EPA did not

attempt to modify a substantive control

requirement of the submitted plan.

Rather, EPA evaluated the State's

analysis plus performed additional

analysis to determine if the plan, as

submitted, fulfilled the substantive

RACM requirement of the Act. As a

general matter, EPA believes that States

should perform their own analyses of

RACM (as well as submitting other

supporting documents for the choices

they make), which is what Texas did in

this instance for the Houston area. The

statute places primary responsibility on

the States to submit plans that meet the

Act's requirements. However, nothing in

the Act precludes EPA from performing

those analyses, and the Act clearly

provides that EPA must determine

whether the State's submission meets

the Act's requirements. Under that

authority, EPA believes that it is

appropriate, though not mandated, that

EPA perform independent analyses to

evaluate whether a submission meets

the requirements of the Act if EPA

believes such analysis is necessary. The

EPA has not attempted to modify the

State's submission by either adding or

deleting a substantive element of the

submitted plan. By virtue of the State's

analysis and EPA's evaluation of it, and

EPA's supplemental RACM analysis for

transportation control measures, EPA

has concluded that the State's

submission contains control measures

sufficient to meet the RACM

requirement.

Comment: Inappropriate grounds for

rejecting RACM. The commenter claims

that EPA's bases for rejecting measures

as RACM are inappropriate

considerations: (a) The measures are

"likely to require an intensive and

costly effort for numerous small area

sources"; or (b) the measures "do not

advance the attainment dates" for the

areas. 65 FR 61134. Neither of these

grounds are legally or rationally

sufficient bases for rejecting control

measures. This comment is essentially

the same as a comment provided on

EPA's October 12, 2000 Notice of

Availability proposing EPA's RACM

action for the three areas of Atlanta,

Washington D.C. and Springfield, MA.

Response: The EPA's approach

toward the RACM requirement is

grounded in the language of the Act.

Section 172(c)(1) states that a SIP for a

nonattainment area must meet the

following requirement, "In general.-

Such plan provisions shall provide for

the implementation of all reasonably

available control measures as

expeditiously as practicable (including

such reductions in emissions from

existing sources in the area as may be

obtained through the adoption, at a

minimum, of reasonably available

control technology) and shall provide

for attainment of the national primary

ambient air quality standards."

[Emphasis added.] The EPA interprets

this language as tying the RACM

requirement to the requirement for

attainment of the national primary

ambient air quality standard. The Act

provides that the attainment date shall

be "as expeditiously as practicable but

no later than * * *" the deadlines

specified in the Act. EPA believes that

the use of the same terminology in

conjunction with the RACM

requirement serves the purpose of

specifying RACM as the way of

expediting attainment of the NAAQS in

advance of the deadline specified in the

Act. As stated in the "General Preamble

for the Implementation of Title I of the

Clean Air Act Amendments of 1990

(General Preamble)" (57 FR 13498 at

13560, April 16, 1992), "The EPA

interprets this requirement to impose a

duty on all nonattainment areas to

consider all available control measures

and to adopt and implement such

measures as are reasonably available for

implementation in the area as

components of the area's attainment

demonstration." [Emphasis added.] In

other words, because of the construction

of the RACM language in the Act, EPA

does not view the RACM requirement as

separate from the attainment

demonstration requirement. Therefore,

EPA believes that the Act supports its

interpretation that measures may be

determined to not be RACM if they do

not advance the attainment date. In

addition, EPA believes that it would be

unreasonable to require implementation

of measures that would not in fact

advance attainment. See 57 FR 13560.

EPA has consistently interpreted the Act

as requiring only such RACM as will

provide for expeditious attainment since

the agency first addressed the issue in

guidance issued in 1979. See 44 FR

20372, 20375 (April 4, 1979).

The term "reasonably available

control measure" is not actually defined

in the definitions in the Act. Therefore,

the EPA interpretation that potential

measures may be determined not to be

RACM if they require an intensive and

costly effort for numerous small area

sources is based on the common sense

meaning of the phrase, "reasonably

available." A measure that is reasonably

available is one that is technologically

and economically feasible and that can

be readily implemented. Ready

implementation also includes

consideration of whether emissions

from small sources are relatively small

and whether the administrative burden,

to the States and regulated entities, of

controlling such sources was likely to be

considerable. As stated in the General

Preamble, EPA believes that States can

reject potential measures based on local

conditions including cost (57 FR 13561).

See Oberv. EPA, 84 F3d at 312 (9th

Circuit 1996).

Also, the development of rules for a

large number of very different source

categories of small sources for which

little control information may exist will

likely take much longer than

development of rules for source

categories for which control information

exists or that comprise a smaller number

of larger sources. The longer time frame

for development of rules by the State

would decrease the possibility that the

emission reductions from the rules

would advance the attainment date.

Texas has determined and we agree that

such additional measures in the HG area

could not be developed soon enough to

advance the attainment date.

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Comment: Failure to quantify

reductions needed to attain sooner:

Even if advancement of the attainment

date were a relevant test for RACM, EPA

has failed to rationally justify its claim

that additional control measures would

not meet that test. To begin with,

neither the Agency nor the states have

quantified in a manner consistent with

EPA rules and guidance the emission

reductions that would be needed to

attain the standard prior to achievement

of emission reductions required under

the NOx SIP call. Nowhere is there an

analysis that shows what it would take

to attain in 2004, 2005, 2006 or 2007.

This comment generally repeats a

comment provided on EPA's October

12, 2000 Notice of Availability

proposing EPA's RACM action for the

three areas of Atlanta, Washington DC

and Springfield, MA.

Response: First, note that while the

commenter makes reference to the NOx

SIP call, Texas is not included in the

mandatory NOx SIP call. However, it

should also be noted that even though

Texas was not included, Texas adopted

control measures for regional NOx

emissions reductions (including in

attainment areas) as part of the HG

attainment demonstration SIP, in a

manner similar to those undertaken by

the states included in the NOx SIP call.

These regional reductions will occur by

May 2003 in Texas. In Michigan v. EPA,

200 WL 1341477 (D.C. Cir. 2000) (order

denying motion to stay mandate

pending appeal from 213 F.3d 663(D.C.

Cir. 2000)) the court held the NOx

control measures could not be required

by EPA until May 31, 2004 in order to

allow sources in subject States 1309

days from the date of the court order to

implement the measures as provided in

the original rule. These regional

measures in Texas are thus being

implemented on a more expeditious

schedule and as expeditiously as is

practicable.

Further, it would be futile for TNRCC

to attempt to quantify the emission

reductions that could be possible for the

HG area to attain prior to the 2007

deadline. With all of the adopted

control measures, and with the

enforceable commitments to achieve the

additional 56 tons/day of NOx emission

reductions needed for attainment, plus

the necessary reliance upon Federal

measures, including the amount of

cleaner on and off-road vehicles that

will enter the fleet, there are simply no

additional measures that EPA is aware

of that are reasonably available or

economically feasible that could be

implemented, much less implemented

in time, to achieve attainment in

advance of when the measures are being

implemented in this plan.

The following respond to the issue of

whether additional specific potentially

available measures are RACM for the

HG area.

Comment: Inadequate RACM analysis:

EPA's RACM analysis is grossly

inadequate in several key respects.

Comment a: EPA's analysis fails to

provide the technical basis and

calculations by which it developed its

emission reduction estimates for various

measures. EPA failed to provide

citations to the literature regarding

estimates of emission reductions for

various TCMs. EPA failed to specify the

level of implementation assumed for

some of the TCMs in the analysis.

Response a: First, note that EPA's

analysis contained in the TSD was

intended to evaluate and in one instance

supplement the TNRCC analysis and

conclusion that all RACM had been

adopted. We evaluated the TNRCC's

technical basis and calculations for the

emission reduction estimates for

controls possible for all of the source

categories in the emission inventory.

Regarding the TCM category, we

provided additional technical analysis

and calculations. The commenter

apparently believes EPA's analysis of

potential TCMs as not being RACM for

the HG area is insufficient, however.

EPA's technical basis for the

supplemental TCM RACM analysis and

the assumptions used in the calculation

of estimated emission reductions from

additional potential TCMs were derived

from a review of the literature on the

implementation and effectiveness of

TCM's. 15 The TCMs evaluated depend

on the level of implementation.

Implementation variables, representing

levels of implementation effort, are

implicit in the range of effectiveness for

each category of TCM. EPA does not

believe it is necessary, or even

practically possible, to evaluate every

explicit variation of TCM's in order to

adequately determine if it is reasonably

available. In summary, the technical

basis is provided in Appendix B to the

TSD and Chapter 7 of TNRCC's SIP. In

conclusion, we determined that at a

reasonable level of implementation, all

potential categories of TCMs taken

together would not be sufficient to

advance the attainment date.

Comment b: EPA's analysis looks at

only a small universe of potential

15 Transportation Control Measures: State

Implementation Plan Guidance, US EPA 1992;

Transportation Control Measure Information

Documents, US EPA 1992; Costs and Effectiveness

of Transportation Control Measures: A Review and

Analysis of the Literature, National Association of

Regional Councils 1994.

measures, and does not evaluate all of

the measures identified in public

comment and other sources. Several

commenters suggested that a variety of

measures were Reasonably Available

and should be included in the SIP.

Response b: It is EPA's position that

the TNRCC's RACM analysis identified

and addressed all potential categories of

stationary and mobile sources in the HG

area, that could provide additional

emission reductions, and measures that

might be considered RACM. The EPA

believes not only that Texas identified

and addressed all the potential source

categories but that it also addressed

identified measures raised by

commenters. The TNRCC considered a

wide range of potential measures,

including all measures adopted in other

severe and serious areas and the

California South Coast's extreme

attainment demonstration SIP.

The following addresses specific

measures that were suggested by

commenters.

VOC Control Measures

Comment: An adequate plan would

emphasize reductions in all precursors

not just one.

Response: The two primary

precursors to ozone are Volatile Organic

Compounds (VOCs) and Oxides of

Nitrogen ( NOx). These classes of

chemicals react in the atmosphere in the

presence of sunlight to form ozone.

Under 182(c)(2), States must base their

attainment demonstration on

photochemical modeling or any other

analytical method determined by EPA to

be at least as effective. Modeling is

generally regarded as the most reliable

basis for ascertaining which precursors

should be emphasized for control in

order to obtain a reduction in ozone

concentration levels. In the HG area, the

photochemical modeling indicates that

NOx emission reductions are much

more effective in reducing ozone and

thus, NOx emission reductions have

appropriately been the emphasis in the

plan's control strategy. As discussed

further in the next comment/response,

EPA agrees that no additional VOC

measures would advance the attainment

date.

Future studies may revise the

emphasis of the control strategy. EPA is

aware that some of the preliminary

results of the Texas Air Quality Study

2000 indicate that reactive VOC's may

need to be considered for additional

control. Further, there is no clear

evidence, at this time, that indicates that

the control of other pollutants, such as

particulate matter, would help in

reducing the ozone concentration levels

in the HG area.

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Comment: A commenter stated that

TNRCC has not developed adequate

VOC controls. The document presents

evidence that categories of emissions

representing the "vast majority" of point

source emissions are regulated but does

not determine whether in fact the

facilities are regulated. The commenter

felt the proper analysis would present

an inventory of controlled emissions

and compare it with total emissions.

Response: EPA believes the analysis

in Chapter 7 of the SIP and in the TSD

does demonstrate further VOC controls

are not required as RACM based on the

information currently available. This

conclusion is based on three factors.

First, EPA believes Texas has regulated

all major sources of VOCs in the HG

area to at least a RACT level. We took

action on these RACT rules in separate

Federal Register actions. We found that

the State had implemented RACT on all

major sources in the HG area except

those that were to be covered by postenactment Control Technique

Guidelines (CTGs)(60 FR 12437, March

7, 1995). Since that time many expected

CTGs were issued as Alternative Control

Technique documents-ACTs. Of the

expected CTGs and ACT's, the HG area

had major sources in the following

categories; batch processing, industrial

wastewater, reactors and distillation,

and wood furniture. We have approved

measures for all of these categories as

meeting RACT.

Batch Processing-July 16, 2001 66 FR

36913

Industrial Wastewater-December 10,

2000 65 FR 79745

Reactors and Distillation-January 26,

1999, 64 FR 3841

Wood Furniture-October 30, 1996, 61

FR 55894

Further, EPA agrees with the

conclusion drawn by Texas in its RACM

analysis that the majority of VOC point

source emissions (whether emitted from

major sources or minors) are already

regulated by the rules contained in

Chapter 115 of the State Implementation

Plan. The State's VOC rules go beyond

RACT level controls for some categories

such as fugitive emissions and gasoline

loading emissions. EPA has approved

Chapter 115 as meeting the RACT

requirements.

Second, because of the particular

chemistry in the HG area VOC controls

are not nearly as effective as NOx

controls in reducing ozone. TNRCC has

demonstrated through modeling that

12-15 tons/day of VOC emission

reductions are needed to achieve the

same ozone benefit as one ton/day of

NOx emission reductions as shown in

Chapter 7 of the October 2001 SIP

revision. Thus, the particular chemistry

in the HG area makes additional ozone

benefits very difficult to achieve

through VOC reductions. In fact,

modeling indicates that if all man made

VOC's were reduced to zero, the area

would not reach attainment.

Third, Texas analyzed the controlled

VOC inventory to determine if any

source categories remained where

additional VOC controls could be

implemented that could advance the

attainment date in light of the modeling

evidence. As discussed previously, EPA

does not believe that section 172(c)(1)

requires implementation of potential

RACM measures that will not be

sufficient to allow the area to achieve

attainment in advance of full

implementation of all other required

measures, in this case, full

implementation of the NOx controls

called for in the plan including the 56

tons/day NOx reductions called for by

the enforceable commitments. In the

TNRCC analysis, a VOC source category

had to have at least 12-15 tons per day

of emissions to warrant further analysis.

This level was chosen because it might

be theoretically possible to reduce these

categories enough to achieve as much as

the equivalent of one ton/day of NOx

reduction. Given that the final 121 tons/

day of point source reductions, out of a

total of almost 600 ton/day of emission

reductions, will not be implemented

until spring 2007 emission reductions

from measures that achieve less than the

equivalent one ton/day of NOx

reductions even if combined with

several measures of similar magnitude

cannot advance the attainment date. The

TNRCC presents in the SIP Narrative,

Chapter 7, a summary of the inventory

that reflects the controlled level of

emissions. Based on the above screening

level one category, storage tanks, was

examined for additional control. Based

on controls in the Alternative

Technique Guideline, only 2.2 tpd of

additional reduction in VOC could be

achieved which is far less than the

equivalent of one ton/day of NOx

reduction and therefore would not

advance attainment.

Texas also reviewed all VOC area

source (as opposed to points source)

categories to see if any categories were

emitting greater than 11 tons/day in

emissions. While some area source

categories emitted more than 11 tons/

day, these categories already are subject

to rules. TNRCC did not believe

additional controls on already regulated

categories would be reasonable in light

of the amount of VOC reductions

needed to achieve ozone benefits.

In summary, the modeling indicates

that it takes substantial VOC emission

reductions to achieve ozone reductions

in the HG area. Already all major

sources of VOC's in HG have RACT in

place. Emission reductions beyond

RACT on major VOC sources may be

achievable but could not achieve

sufficient ozone benefit for the HG area

to achieve attainment in advance of the

measures in the SIP we are approving

today. Significant area source categories

are also regulated. Therefore, no

emission reduction measures were

identified that would achieve

attainment in advance of the measures

contained in the plan.

Comment: For States that need

additional VOC reductions, this

commenter recommends a process to

achieve these VOC emission reductions,

which involves the use of HFC-152a

(1,1 difluoroethane) as the blowing

agent in manufacturing of polystyrene

foam products such as food trays and

egg cartons. HFC-152a could be used

instead of hydrocarbons, a known

pollutant, as a blowing agent. Use of

HFC-152a, which is classified as VOC

exempt, would eliminate nationwide

the entire 25,000 tons/year of VOC

emissions from this industry.

Response: This comment was not

provided to TNRCC. EPA has met with

the commenter and has discussed the

technology described by the company to

reduce VOC emissions from polystyrene

foam blowing through the use of HFC152a (1,1 difluoroethane), which is a

VOC exempt compound, as a blowing

agent. Since the HFC-152a is VOC

exempt, its use would give a VOC

reduction compared to the use of VOCs

such as pentane or butane as a blowing

agent. However, EPA has not studied

this technology exhaustively. It is each

State's prerogative to specify which

measures it will adopt in order to

achieve the additional VOC reductions

it needs. In evaluating the use of HFC152a, States may want to consider

claims that products made with this

blowing agent are comparable in quality

to products made with other blowing

agents. Also the question of the over-all

long term environmental effect of

encouraging emissions of fluorine

compounds would be relevant to

consider. This is a technology which

States may want to consider, but

ultimately, the decision of whether to

require this particular technology to

achieve the necessary VOC emissions

reductions must be made by each

affected State. Finally, EPA notes that

under the significant new alternatives

policy (SNAP) program, created under

CAA § 612, EPA has identified

acceptable foam blowing agents many of

which are not VOCs (http://

www.epa.gov/ozone/title6/snap/).

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In the case of the HG area, the

analysis in chapter 7 did not show this

category of emissions as one with more

than 11 tons/day of emissions so, as

discussed in a previous comment, there

cannot possibly be enough emission

reductions from this category to achieve

sufficient ozone benefit for the HG area

to reach attainment in advance of the

full implementation of the measures in

this SIP.

Comment: Two commenters suggested

that a portable gasoline container buy

back program should be adopted in the

HG area to introduce gasoline containers

meeting the California Air Resources

Board (CARB) standards to the HG area.

It was estimated based on CARB

experience that controls on containers

would be able to achieve 23 tpd of VOC

reductions in the HG area.

Response: This measure was

suggested to TNRCC as a replacement to

their Commercial Lawn Service

operating restrictions. TNRCC evaluated

the measure and decided the measure

would not achieve equivalent

reductions to the operating restrictions.

EPA is aware that CARB has projected

significant emission reductions from

this measure. This is based on their

studies of the emissions from

evaporation and spillage from gasoline

containers in California. TNRCC in their

RACM analysis of the HG emission

inventory, however, did not identify

this source category, i.e., gasoline

containers, as having the same level of

emissions and therefore the potential to

achieve the same level of emission

reductions as was found in California.

TNRCC used EPA approved

methodology to develop its inventory.

EPA concludes, based on the record

supporting the State's RACM analysis,

that Texas used appropriate

assumptions for determining emission

reductions from this measure. Based on

the emission estimates contained in the

approved inventory, EPA agrees with

Texas that this measure cannot be

considered RACM at this time because

the measures cannot achieve sufficient

ozone benefit for the HG area to achieve

attainment in advance of the full

implementation of the measures in the

SIP we are approving today. Future

study of this portion of the inventory

utilizing information developed by

CARB may indicate that more emissions

arise from this category in the HG area

and this measure may have to be

revisited.

Comment: One commenter pointed to

the results of the Channelview Source

Reduction Project as evidence that

significant levels of VOC emission

reductions can be achieved. The

Channelview Project resulted in the

following improvements: Additional gas

flow meters, reduced flaring of off-spec

product, elimination of flaring of extracontract product, improved flare

systems, and prevention of unnecessary

shutdowns.

Response: The November 14, 2000

"Source Reduction Project, Report on

Phase I" documents the cooperative

effort between the Community Advisory

Panel and Lyondell and Equistar

(CAPLE) to reduce air emissions at these

companies. It documents several

improvements and significant emission

reductions that have been made at these

plants through focusing on source

reduction. It is not clear from the report,

however, whether or not the measures

instituted by these companies have

general applicability within the

chemical industry. The measures taken

by these companies to reduce emissions

have promise as measures that can

achieve emission reductions throughout

the HG area but it will take further study

by us and the State to determine if they

can be applied to other facilities, are

technically and economically feasible

and achieve reductions that could

advance attainment, and thus can be

considered potential RACM for the HG

area. Therefore, at this time, EPA cannot

find these measures feasible. EPA agrees

with Texas that this type of project

cannot currently be considered RACM.

Comment: One commenter suggested

that the State should reduce fugitive

VOC emissions by 90%.

Response: The commenter did not

suggest how the 90% emission

reduction from fugitive VOC emissions

could be achieved. EPA is not aware of

any technology or programs that have

been demonstrated to achieve this level

of reductions. TNRCC already has in

place a leak detection and repair

requirement that goes beyond the levels

in EPA's control technique guidelines to

control refinery and chemical plant

fugitive emissions. EPA has approved

this requirement for fugitive emissions

as meeting the RACT requirement for

the HG area. Based on the above, EPA

concludes that this measure is not

technically feasible at this time.

Upset Emissions

Comment: TNRCC has failed to adopt

reasonably available control measures

for controlling upset emissions because

the TNRCC rules fail to meet at a

minimum EPA guidance for upset

emissions. The rule violates the

requirements regarding creating an

affirmative defense because (1) it is a

blanket exemption, (2) it covers sources

whose individual contributions of

pollutants have the potential to cause an

exceedence, (3) it covers both penalties

and injunctive relief, and (4) it could be

interpreted as barring citizen and/or

EPA enforcement action.

Response: On November 28, 2000,

EPA issued a direct final approval of a

revision to the Texas SIP addressing

excess emissions from start-up,

shutdown, malfunction and

maintenance. 65 FR 70792. In that

notice, EPA explained that it

determined that the rule was consistent

with the EPA guidance referenced by

the commenter, "State Implementation

Plans: Policy Regarding Excess

Emissions During Malfunctions, Startup

and Shutdown," September 20, 1999.

This determination included EPA's

conclusion that the Texas rule does not

provide an exemption from compliance

for periods of excess emissions. No

adverse comments were received and

EPA's approval became effective on

January 29, 2001. Through the proposed

actions on which EPA is taking today,

EPA is not re-opening its past approval

of SIP requirements. Thus, the

commenters attempt to now raise issues

about whether EPA's approval of that

rule was appropriate are untimely.

Point Source NOx Controls

Comment: The Phase II NOx limits

agreed to by OTC States are clearly

RACM for all areas, as they are widely

in effect. States that have not adopted

such measures have not adopted

enforceable NOx RACT limits for all

relevant facilities. It is not sufficient for

States to assert that they will adopt

additional NOx controls if needed.

Response: That the OTC states have

implemented the OTC Phase II NOx

limits does not automatically prove that

these limits are RACM for all areas. EPA

concedes that the wide-spread adoption

of such programs and EPA's own

analysis of NOx control on large

stationary sources would warrant

consideration whether such limits meet

the technological and economical

feasibility criteria of RACM and would

advance attainment. However, such an

analysis is not relevant in the case of the

HG ozone nonattainment area. Texas

has already adopted programs for the

HG area to implement limits that are

more stringent than the OTC Phase 11

limits.

Comment: A commenter suggested

energy efficiency improvements are not

just for residential and commercial

buildings and suggested savings could

be achieved by more efficient motor and

drive systems.

Response: We agree that improved

energy efficiency is a desirable method

of reducing air emissions. There are

difficulties in including such measures

in a SIP because it is not always clear

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where the benefits of the reduced

electrical demand will occur. The

reduced demand could result in

emission reductions outside the HG

area. There are initiatives in Texas to

reduce growth in demand in Texas such

as the State wide building codes

established by Senate Bill 5. The State

of Texas has committed to further

examine the benefits and methods of

improving energy efficiency for possible

inclusion in the SIP at the mid-course

review. EPA concludes that there is not

enough information at this time to

determine the appropriate emission

benefits and therefore energy efficiency

cannot currently be considered RACM.

Comment: Just as Integrated Resource

Planning (IRP) for electric utilities

resulted in demand side management

programs that conserved electricity, IRP

for natural gas utilities will have the

same impact on conserving natural gas

usage and resulting emissions. A

number of states have effectively

implemented IRP for natural gas.

Response: As noted above, EPA agrees

that improved energy conservationregardless of the form of energy-is a

desirable method of reducing air

emissions. Since such measures would

likely have to rely on voluntary efforts,

the State would have to estimate the

effect on emission reductions that

would result. Putting in place even a

voluntary effort to conserve natural gas

that could be quantified in terms of its

emission reduction benefits would

likely require a significant amount of

time. EPA is aware that the State had

devoted a tremendous amount of

resources in developing and adopting

the number of control measures that it

did for the HG area's one-hour ozone

SIP, and even with that had to commit

to fill a shortfall of 56 tons/day of NOx

reductions. EPA believes it is unlikelygiven the time spent on the bulk of the

SIP-that the State had the time to

develop such a quantifiable voluntary

program that would have yielded

enough NOx reductions to advance the

attainment date. Furthermore, it appears

unlikely that such a quantifiable

program could be put into place in

sufficient time to advance the

attainment date given the resources that

the State will have to spend over the

next several years simply developing

and adopting the emission controls to

achieve the 56 tons/day NOx emission

reductions. Therefore, EPA believes that

this measure is not RACM, at this time,

for the HG area.

Comment: Stringent Standards for

Stationary Diesel Engines: The TNRCC

should establish the same requirements

for new and existing stationary diesel

engines in the HG area that are not used

exclusively during infrequent

emergency or backup situations.

Response: The State received a similar

comment. In their response they

explained that based on information in

the emissions inventory and contact

with diesel engine vendors and others

familiar with the stationary diesel

engines in the HG area, the State is

unaware of any existing stationary

diesel engines that are being operated in

situations other than generation of

electricity in emergency situations or

operation for maintenance and testing.

The Chapter 117 rule requires that all

testing and maintenance be done

outside the hours of 6 am to 12 am. As

discussed in the comments on the

modeling inputs, emissions in the

morning are the most conducive to

ozone formation. Emissions outside this

period are much less conducive to

ozone formation. Therefore, the rules for

maintenance represent RACM for the

HG area.

TNRCC believes and EPA agrees that

few existing engines will be moved from

emergency service to routine or peak

shaving operations for the following

reasons. Any existing engines at a site

with a collective design capacity to emit

(from units with chapter 117 emission

limits) greater than ten tpy of NOx are

subject to the Chapter 101 mass

emissions cap and trade program if they

choose to increase their operation to 100

hours per year or more (based on a

rolling 12-month average) and, in

addition to having to comply with the

Chapter 117 rules, will only be issued

NOx emissions allocations based on

their historical activity level which

would be much lower than 100 hrs/year.

Existing engines theoretically could be

switched to peak shaving service up to

100 hours/year but in reality only about

40 hours/year would be available for

this type of operation. The remaining

time would have to be used for normal

routine testing of the engines. It is

unlikely that the profit from sale of

electricity, would justify the cost of the

modifications to the switching system

for only about 40 hours of operation.

EPA concludes that additional control

beyond the existing program is not

economically feasible and therefore

would not represent RACM.

On-Road Control Measures

Comment: Two commenters suggested

that 15 ppm sulfur gasoline should be

adopted in the HG area as a reasonably

available control measure.

Response: The Act preempts states

from establishing state fuels under

section 211(c)(4)(A). Waivers from

preemption are possible under section

211(c)(4)(C) if the state can show

necessity for that fuel to meet the

NAAQS, and if no other reasonable or

practicable non-fuel measures exist that

could be implemented in place of a state

fuel. For a state to obtain a waiver of

preemption, an acceptable

demonstration must be submitted to

EPA that can justify the need for a

particular state fuel. This provision of

the Act was included to discourage the

development of a patchwork of fuel

requirements from State to State.

Texas considered adopting a 15 ppm

sulfur standard in gasoline, but

withdrew the proposal once the 30 ppm

Federal low sulfur gasoline standard

became final. They received comments

both for and against the proposal.

Comments against cited excessive costs

when compared with the emissions

benefit, the difficulties in producing a

boutique fuel, and anticipated

distribution problems and conflicts with

on-going efforts to comply with the

federal low-sulfur requirements of 30

ppm. Texas only projected a 1.15 ton/

day of emission reduction from the

institution of a 15 ppm fuel. The BCCA

estimates that the cost of these

reductions is $400,000/ton to refiners.

Based on TNRCC cost estimates, the cost

is over $500,000/ton to consumers.

Because of the general preemption in

the Act and the low projected cost

effectiveness, EPA does not consider

this fuel requirement to be RACM for

the HG area.

Comment: One commenter suggested

that Texas adopt diesel fuel that meets

a 15 ppm sulfur standard by 2003.

Response: Texas adopted a low

emission diesel fuel in December 2000,

that includes a low sulfur component.

The state's low sulfur component

phases in beginning May 1, 2002, with

500 ppm sulfur statewide for onhighway use and 110 counties in east

and central Texas for non-road use. On

June 1, 2006, the sulfur level drops to

15 ppm in east and central Texas for offhighway use to be consistent with

Federal low sulfur diesel fuel for onhighway use. Thus, TNRCC has already

adopted a standard more stringent than

the Federal Standards.

In order for Texas to adopt statewide

fuel controls that are more stringent

than Federal controls, the state must

show necessity to achieve the NAAQS

in the nonattainment areas and justify

implementing a fuel measure over

nonfuel measures statewide. Texas has

requested and EPA is granting in a

separate Federal Register a waiver

under 211(c)(4)(A) for this fuel. EPA

does not believe the accelerated

schedule of implementing the low

sulfur standard suggested by the

commenter is reasonable or will result

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in ozone benefits because the low sulfur

requirement does not result in NOx

emission reductions by itself but instead

enables catalyst technologies. Under

Federal regulations, new vehicles will

not be required to meet the new

emission standard enabled by low sulfur

diesel until 2007. Therefore, EPA does

not consider calling for these fuel

requirements earlier as suggested by the

commenter to be RACM.

Comment: Two commenters gave

comments that the Inspection and

Maintenance Program could be

improved. One said that adequate

resources to develop and implement an

I/M program must be assigned;

otherwise, the program cannot be

considered credible. A second

commenter stated that the program

should be established based on where

the vehicle owner usually works.

Response: EPA has reviewed the I/M

program developed by the State of

Texas. In a separate Federal Register

notice, we are approving the State's I/M

program. The new program, using the

Accelerated Simulation Mode (ASM)

test method will be implemented in all

eight counties of the HG nonattainment

area and covers more vehicles than are

required by the Federal I/M rules.

Expanding the program to cover

vehicles not registered in the program

area is beyond the scope of the Federal

rules and would be extremely difficult

to implement and enforce. Further, the

prior, less stringent program met the

minimum I/M requirement for the HG

area. The new program goes beyond

those requirements. As such, we believe

TNRCC has adopted an I/M program

that meets the RACM requirement. We

agree that adequate resources will have

to be devoted to the implementation of

this program by the Texas Department

of Public Safety and TNRCC for the

goals of the program to be achieved. At

this time, we have no information to

support a determination that the

program will not be fully implemented.

Comment: One commenter suggested

that public and large commercial fleets

be required to have low emitting

vehicles.

Response: Texas adopted Fleet

provisions and submitted them to EPA

on August 27, 1998 as the Texas Clean

Fuel Fleet (CFF) substitute plan. EPA

approved this provision on February 7,

2001 (66 FR 9203) as meeting the Clean

Fuel Fleet Requirements of the Act.

These provisions ensure that fleets meet

a reasonable level of control in serious

and above nonattainment areas. Texas'

CFF substitute plan relies on a State

fleet program-the Texas Clean Fleet

(TCF) program-supplemented with

additional volatile organic compound

(VOC) and nitrogen oxide (NOx)

emission controls. The emission

reductions for Texas' plan greatly

exceed the reductions that would have

been achieved with the Federal CFF

program. Therefore, the State's

substitute plan will meet the Federal

CFF requirement for VOC and NOx

emissions reductions. EPA believes that

TNRCC has instituted RACM for this

source category.

Comment: One commenter suggested

that the State should encourage the

early introduction of Tier 2 vehicles.

Response: In the last session, the

Texas legislature passed Senate Bill 5

which includes an incentive program

for the purchase of vehicles that meet

the more stringent Tier II vehicle

standards. This program should result

in more cleaner vehicles coming into

use in Texas then would be required

under the Federal Program. It is

uncertain, however, how much

additional emission reduction will come

from this program as it apparently is the

first of its kind in the country.

Therefore, EPA concludes that further

acceleration of this program would not

constitute RACM for the HG area.

Comment: A commenter suggested

that non-USA registered trucks should

be subject to an I/M inspection.

Response: It is not clear whether the

State has the legal authority to require

trucks from a foreign country to be

inspected. As a practical matter, there

are no proven test methods to employ

for Diesel I/M programs. Therefore, this

cannot be considered a reasonably

available measure. Comment: One commenter felt all

highway construction in HG area should

be limited. The HG area must absorb ongoing expansions at the airports,

medical center plus population and job

growth. There is no room for the above

ongoing new emissions generating

projects let alone any new large

emissions generating projects. The same

commenter later said that the

Transportation Improvement Plan and

other proposed changes to Regional

Highway system must demonstrate full

conformity with the Act.

Response: EPA agrees that the

Regional Transportation Plans must

demonstrate conformance to the State

Implementation Plan consistent with

section 176(c) of the Act and our

transportation conformity rules at 40

CFR 93.100; however, these are separate

requirements from demonstrating

attainment of the NAAQs.

Transportation conformity is the process

whereby the transportation plans have

to be reconciled with and show they are

consistent with the plans for attainment.

In this SIP, the State has established an

emissions budget for motor vehicle

emissions consistent with attainment.

The Houston/Galveston Area Council

will have to show for all future plans,

taking into account existing roads and

future growth how they will conform to

these budgets. Given the severe impact

a ban on road construction would place

on the HG area, EPA concludes that this

is not a reasonably available measure.

Comment: One commenter suggested

the State institute an auto license fee

tied to actual vehicle NOx emission

rates.

Response: EPA is not aware of

anywhere where this measure has been

instituted. It is not clear how much

emission reductions could be achieved

and at what fee levels. Because of the

lack of localized information on the

costs and benefits of this program this

cannot be considered a RACM.

Texas is already instituting a program

to provide rebates for the purchase of

vehicles meeting the cleanest Tier II

standards. This program should

influence positively the introduction of

cleaner vehicles into the fleet.

Off Road Measures

Comment: Three commenters

recommended measures they felt were

appropriate to control emissions from

construction equipment. One

commenter felt that all diesel equipment

should be required to register. He felt

this would result in a 70% reduction in

emissions. Two other commenters felt

that all State and Local Government

contracts should have requirements that

require lower emission equipment be

used.

Response: The Texas legislature has

passed an incentive program that will

pay for the cost of upgrading diesel

equipment to meet cleaner standards.

Texas plans to direct 24.7 million

dollars/year to the HG area from the

Texas Emission Reduction Program

passed under Senate Bill 5. Based on

experience from similar programs in

California, we expect substantial

reductions to be achieved. We therefore

believe that additional measures to

reduce emissions from this category are

not RACM.

Comment: One commenter suggested

the following measures to achieve

additional emission reductions from

aircraft operations: (1) Mandatory

Powering of Jets at gates with Electric

Power (2)Reduced Idling on the runway

(3) Congestion Pricing at Rush Hours at

Airports.

Response: First, the State has

executed agreed Orders with the major

airlines and the City of Houston to

achieve emission reductions from

Ground Support Equipment (GSE) at

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airports in the HGA area. These Orders

require a phased-in replacement of

current combustion engine equipment

with electric equipment or to achieve

equivalent reductions. Equipment

powering jets at gates is included in the

definition of GSE; thus, over a period of

time jets at gates will be powered with

electric equipment or equivalent

emission reductions will be achieved.

Second, although planning of airline

operations during rush hours to reduce

idling on runways to reduce emissions

may have merit, the State does not have

the authority to impose regulations on

airlines to require this planning. The

Federal Aviation Administration has

jurisdiction over airline operations once

the aircraft leaves the gate and State

regulation is pre-empted. Third, since

the State has no authority to control

airline operations, and congestion is a

function of the higher level of

operations during rush hours,

congestion pricing is likely to place an

unnecessary economic burden on the

traveling public with no air quality

benefits. State controls on pricing are

expressly preempted by the Air

Deregulation Act. Therefore, EPA

concludes that such measures are not

reasonably available.

Transportation Control Measures and

Land Use

Comment: Transportation Control

Measures as RACM: EPA gives virtually

no consideration to the emission

reduction benefits of transportation

programs, projects and services

contained in adopted regional

transportation plans (RTPs), or that are

clearly available for adoption as part of

RTPs adopted for a nonattainment area.

In addition, it is arbitrary and capricious

for EPA not to require as RACM

economic incentive measures that are

generally available to reduce motor

vehicle emissions in every

nonattainment area. One commenter

provided a report "Studies on the Travel

and Air Quality Effects of Transit, Land

Use Intensification, and Auto Pricing

Policies." The commenter felt this

report contained measures that are

RACM.

Response: A similar comment was

received in response to the analysis EPA

performed as part of EPA's notice of

availability where an analysis of

Reasonably Available TCMs was

performed for four serious ozone

nonattainment areas: Greater

Connecticut, Springfield, MA,

Washington, DC and Atlanta. In the

Technical Support Document for the

July 12, 2001 proposal on RACM, EPA

performed a similar analysis for the HG

area. This analysis was performed to

evaluate the State's conclusion that

further TCMs are either economically

infeasible or would not advance

attainment.

EPA's TSD for the July 12, 2001

proposal on RACM for the HG area does

consider transportation programs,

projects and services that are generally

adopted, or available for inclusion in a

nonattainment area's SIP. The RACM

analysis includes seven broad categories

and twenty-seven subcategories of

Transportation Control Measures

(TCMs) that represent a range of

programs, projects and services. The

inclusion of a TCM in an RTP or TIP

does not necessarily mean that it meets

EPA's criteria for RACM and must be

included in the SIP. The measure must

also contribute to expeditious

attainment. EPA concluded from its

analysis that the State's assertion that

further TCMs are not RACM was

appropriate.

Some of these TCMs, such as parking

cashout, transit subsidies, and parking

pricing, are explicitly economic

incentive programs. Furthermore, these

categories of TCMs, as well as most of

the others, could be infinitely

differentiated according to criteria, such

as the method of implementation, level

of promotional effort or market

penetration, stringency of enforcement,

etc. The application of economic

incentives to increase the effectiveness

of a TCM is one such criterion. These

implementation variables, representing

levels of implementation effort, are

implicit in the range of effectiveness for

each category of TCM. EPA does not

believe it is necessary, or even

practically possible, to evaluate every

explicit variation of TCM's in order to

adequately determine if it is reasonably

available.

From the analysis for the HG area,

EPA identified 1.7 to 22.4 tpd of NOx

emission reductions as theoretically

achievable from TCMs. The EPA

believes that emission reductions which

are in the low- to mid-point range of

EPA's analysis are achievable with

careful planning, adequate

implementation resources, aggressive

public information programs and a

sustained commitment by the

implementing agencies. TNRCC has

identified in its SIP the implementation

of a wide range of TCMs which are

projected to achieve 4.86 tpd of

emission reductions. The TCM's

identified in the HG analysis are in the

low- to mid-point range. Additional

emission reductions beyond this level

that could be reasonably achieved

would not advance attainment given

that the final 121 tons/day of NOx

emissions reductions from the point

source rules will not be achieved until

spring of 2007.

There are many important reasons

why a state, regional, or local planning

agency might implement TCMs in an

integrated traffic management plan

beyond whatever air quality benefits the

TCMs might generate, including

preserving open space, water shed

protection, avoiding sprawl, mitigating

congestion, and "smart growth"

planning generally. So the fact that

TCMs are being implemented in certain

ozone nonattainment areas does not

necessarily lead one to the conclusion

that those TCMs represent mandatory

RACM when they are analyzed

primarily for the purpose of determining

whether they would advance the ozone

attainment date.

The report, "Studies on the Travel

and Air Quality Effects of Transit, Land

Use Intensification, and Auto Pricing

Policies," provides case studies from

two areas of the country, Portland OR,

and Sacramento, CA and a literature

survey. EPA's analysis included

consideration of measures in the same

categories as provided in this report.

Based on this analysis, EPA does not

believe implementation of these

measures would advance the HG area's

attainment. Further, as stated in the

General Preamble, 57 FR 13560, EPA

believes that local circumstances vary to

such a degree from city-to-city that a

national presumption of RACM is not

appropriate. It is more appropriate for

States to consider TCM's on an areaspecific basis and to consider groups of

interacting measures, rather than

individual measures. Therefore, based

on EPA's analysis, EPA cannot conclude

that these measure suggested in the

report are RACM for the HG area.

Comment: A number of specific TCMs

and economic incentive programs to

reduce vehicle miles traveled were

identified by various commenters.

These include: Telecommuting, satellite

offices, college/university traffic control

measures, Bike and Walk pathways,

Increased Government Use of the Web,

Voluntary No Drive Days, Trip

Reduction Ordinances, Employer Based

Transportation Management, Road

Pricing, Ride Share Incentives,

Insurance Pricing, Commuter Choice,

Parking Cashout, Taxes on Paid Parking,

Congestion Pricing, Location Efficient

Mortgages, Fee Bate on Suburban

Mortgages, Tax Incentives for Living

Near Place of Employment, Incentives

for Transit Oriented Development and

improved incident response.

Response: As stated in the previous

response, EPA does not believe it is

necessary, or even practically possible,

to evaluate every explicit variation of

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TCM's in order to adequately determine

if it is reasonably available. EPA notes

that many of the measures listed above

are being encouraged in the HG area as

part of the commuter choice program

such as telecommuting, ride share

incentives, and employer based

transportation management. As

discussed in the previous comment

Texas has identified 4.83 tpd of NOx

emission reductions from reasonably

available Transportation Control

Measures which, based on the literature

survey, falls into the low to midpoint of

emission reductions theoretically

achievable from these programs. Also,

as noted above, this small amount of

emissions reductions would not

advance attainment prior to the

implementation of all other measures in

the plan. Therefore, EPA believes the

small amount of additional reductions

that could reasonably be achieved

would not advance attainment.

Comment: EPA's analysis also

completely fails to consider the

additional benefits likely from

combined implementation of

complementary TCMS e.g., parking

management along with transit

improvements. It is arbitrary and

irrational for EPA to assume that these

measures can and will be implemented

in complete isolation from one another.

Response: EPA recognizes that many

control measures, particularly TCMS,

are more effective if done in conjunction

with others. EPA maintains, however,

that it is not practically possible to

analyze a seeming infinite set of

combinations of measures for possible

benefits. The EPA's analysis did look at

all measures in various categories at a

reasonable level of implementation and

concluded that as a whole these

categories of measures, taken together,

would not advance attainment or would

otherwise not be reasonably available.

General RACM Comments

Comment: One commenter suggested

that the SIP should include enforcement

of New Source Review such that

grandfathered plants would get

emissions permits with emission limits

that are identical to new construction as

of June 2001.

Response: Existing industrial sources

in the HG area are required to comply

with Chapter 115 for VOC and Chapter

117 for NOx controls regardless of

whether the sources are permitted or

grandfathered. These rules have been

approved as RACT. In addition all

sources, both existing and new, are

subject to the NOx mass emissions cap

in Chapter 101. Requiring all existing

sources to obtain permits is not likely to

result in any additional emission

reductions beyond those achieved by

the Chapter 115 and Chapter 117 rules.

Comment: One commenter

incorporated in their comments to EPA

their comment to the TNRCC where

they encouraged the State to use Market

Incentives to the extent possible.

Response: We believe the State has

employed market based incentives in a

variety of programs. The cap and trade

program and the Texas Emission

Reduction Program are the two main

examples of programs that use markets

to provide significant flexibility in how

emission reductions are achieved.

Comment: STAPPA's 1993 report

recommended adoption of California or

South Coast Air Quality Management

District (SCAQMD) controls/limits for

various source categories. The

commenter mentions further possible

control measures as well, and notes that

none of the states offered consideration

of these measures accompanied by

reasoned explanations for their

rejection.

Response: Texas used the EPA survey

"Serious and Severe Ozone

Nonattainment areas: Information on

Emissions Control Measures Adopted or

Planned and Other Available Control

Measures" as a basis to determine if all

reasonably available control measures

had been implemented. This report

includes measures from the STAPPA

1993 report and other measures that

EPA considers potentially reasonably

available. TNRCC did not identify any

additional measures that were

considered reasonable for the HG area.

Comment: By absorbing ozone and

reducing air temperatures, trees actually

account for a small but measurable

reduction in ozone levels. The EPA

should work with TNRCC to encourage

public funding for tree planting and

local ordinance that require canopy

cover in new private development.

Response: EPA agrees that tree

planting can result in a possible

reduction in ozone formation.

Unfortunately, at this time, these

benefits are difficult to quantify. Efforts

are currently underway to complete a

modeling study to quantify the impacts

of various urban heat island mitigation

strategies using the photochemical

model. It is hoped that these studies

will provide information that will allow

tree planting strategies to be included as

a creditable portion of the SIP at a later

date, perhaps for the mid-course review

SIP submission. Texas is involved in

this effort and intends to incorporate

such programs in the SIP should they

prove effective and reasonably available.

C. Response to Comments on Local

Measures

1. Comments on Speed Limits

Comment: Three commenters

indicated the speed limit measure

would not be enforced or was not

enforceable and that EPA should not

give credit unless TNRCC develops a

mechanism to demonstrate that speeds

actually decrease.

Response: The mechanism to enforce

reduced speed limits is already in place

with the Department of Public Safety

and local municipalities. EPA

acknowledges that it is unlikely that

100% of vehicles will comply with the

new speeds. The modeling projections

assume that the average speed will be

10% higher than the posted speed limits

on roads that currently have average

speeds above the reduced speeds. Thus,

the State has made reasonable

assumptions to anticipate the level of

compliance with this rule. We believe

we can approve these reasonable

planning assumptions about speed

reductions. It would not be appropriate

to wait until Texas proves that the

speeds have been reduced to give credit

for this measure just as we would not

wait until industrial sources have

accomplished their emission reductions

before approving point source rules. We

do believe that the effectiveness of this

measure, as with all measures, should

be monitored. Data is collected in the

HG area by Transtar and Texas

Department of Transportation. This data

could be used to evaluate the efficacy of

this measure in reducing speeds.

2. Comments on the VMEP

Comment: The plan includes

impermissible reductions for

"Voluntary controls." EPA has no legal

basis for issuing SIP credit for the VMEP

program; the VMEP measures do not

meet the test of being real, permanent,

and enforceable to qualify for emission

reductions.

Response: EPA disagrees with the

comments, and continues to believe that

the voluntary measures proposed by

Texas for inclusion in the SIP are

approvable under the Act. EPA

acknowledges that, by themselves, the

measures would not be approvable,

because, as noted by the commenter,

they are not enforceable against the

entities producing the emissions

reductions and thus do not meet the

enforceability requirement of section

110(a)(2)(A). However, EPA did not

propose to approve the measures by

themselves. EPA proposed to approve

them only in conjunction with an

enforceable commitment by the state of

Texas to monitor implementation of the

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voluntary measures, determine whether

the anticipated reductions from the

measures were in fact achieved, and if

not to either alter the program such that

the requisite reductions will be

achieved, adopt substitute measures, or

demonstrate that the attainment and

maintenance goals of the ozone SIP can

still be met without the reductions from

these measures. Thus, EPA did not

propose to approve voluntary measures

as satisfying the enforceability

requirements of section 110. Rather,

EPA proposed to approve the voluntary

programs into the SIP as part of the

overall attainment scheme, and

proposed to approve the state's

enforceable commitment to monitor,

assess, and rectify any shortfall as

meeting the enforceability requirements

of the Act.

EPA continues to believe that this

approach is a proper means of

encouraging implementation of

innovative mobile source control

measures while providing an

enforceable SIP backstop measure.

Ideally, the voluntary measures will

produce the estimated emissions

reductions without need for any state

backfill or federal or citizen

enforcement. However, should any

shortfall result, Texas will be bound by

the enforceable SIP commitment to

rectify the problem and supply the

necessary emissions reductions. Both

EPA and private citizens retain all of

their rights under sections 113 and 304

to bring appropriate enforcement

pressure to bear against the state should

Texas fail to monitor, assess or fill any

shortfall in emissions reductions

resulting from implementation of the

voluntary measures in the SIP. Contrary

to the commenter's allegations, the

emissions reductions associated with

the voluntary measures in the HG area

SIP are required to be achieved; it is

however the state and not the

individuals implementing the voluntary

measures who must ultimately produce

them.

Comment: Two commenters raise

numerous arguments concerning the

unenforceability of the voluntary

measures.

Response: The commenter makes no

mention of the enforceable state

commitment other than to refer to it as

insufficient. This statement without

further explanation does not give EPA

any guidance on the alleged inadequacy

of the commitment nor how the

commenter would have EPA improve

upon it. Therefore, EPA continues to

maintain that the commitment is

approvable as meeting the enforceability

requirements of the Act. In the past,

EPA has often approved enforceable

state commitments to take future actions

under the SIP, and these actions have

been enforced by courts against states

that have failed to comply with those

commitments. 16 EPA believes that the

Texas commitments associated with the

voluntary measures portion of the SIP

are similarly enforceable and thus

approvable. NRDC alleges that the Act

requires all control measures to be

enforceable against individual polluters

and not just against states. However,

many mobile source control measures

are enforceable only against the state or

local transit operator, and not the

individual entities actually producing

the emissions reductions, for instance in

the case of state obligations to establish

vehicle inspection and maintenance

programs or to purchase buses or

expand transit systems. The Act does

not require federal enforcement

capability against individual vehicle

owners or transit users prior to approval

of such programs into the SIP. 1 5

Comment: A commenter alleges that

the public cannot adequately monitor

implementation of the voluntary

measures nor determine whether the

emissions reductions are achieved. The

commenter admonishes the State to

commit to a solid evaluation or auditing

framework to monitor performance of

measures in the VMEP.

Response: Texas is required by its

enforceable commitment to conduct the

evaluation and audit mentioned by ED,

and should make such assessments

available to the public in the normal

course of administrative practice. The

commenters also claim that the state

itself has raised concerns about the

emissions reductions that will be

achieved from these measures. Such

concerns may be valid, nevertheless

Texas has made a commitment to fill

any shortfall in emissions, which both

EPA and citizens can enforce under the

Act.

16 See, Trustees for Alaska v. Fink, 17 F. 3d 1209

(9th Cih. 1994); Coalition Against Columbus Center

v. City ofNew York, 967 F. 2d 764 (2d. Cir. 1992);

Citizens for a Better Environment v. Deukmejian,

731 F. Supp. 1448, reconsideration granted in part,

746 F. Supp. 976 (N.D. Cal. 1990); American Lung

Ass'n of New Jersey v. Keane, 871 F.2d 319 (3d Cih.

1989); NRDC v. New York State Department of

Environmental Conservation, 668 F. Supp. 848

(S.D.N.Y. 1987); Council of Commuter

Organizations v. Gorsuch, 683 F.2d 648 (2d Cir.

1982) and Friends of the Earth v. EPA, 499 F.2d.

1118 (2d. Cir. 1974).

17 The Act does require that enhanced I/M

programs include state enforcement through denial

of vehicle registration without proof of compliance

with inspection requirements. However, the

enforceable SIP requirement is to develop a

program that includes registration denial, and any

enforcement would be against the state for failing

to deny registration. The Act does not contemplate

enforcement actions against individual vehicle

owners attempting to register their vehicles.

Comment: A commenter makes

various arguments about the

unacceptability of the voluntary

measures program stemming from the

stationary source permitting program

under Title V of the Act.

Response: Title V is totally irrelevant

to these mobile source programs. The

voluntary measures program Texas has

included in the HG SIP applies only to

mobile sources that are not subject to

regulation under the Title V stationary

source operating permit program.

Comment: EPA can not alter its past

interpretations without completing

notice-and-comment rulemaking.

Response: EPA believes that this

action is consistent with its past

interpretations that enforceable state

commitments to take future action are

approvable SIP measures. For example,

see EPA actions approving California

plans at 62 FR 1150 ( January 8, 1997)

and 65 FR 18903 (April 10, 2000). In

addition, this action is consistent with

the guidance that EPA issued in 1997

indicating its belief that voluntary

programs could be approved in

conjunction with enforceable state

commitments to fill any resultant

shortfall.' 8 The individual SIP approval

actions implementing the VMEP

guidance constitute the notice-andcomment rulemaking required to

effectuate action under the guidance.

Thus, this SIP rulemaking satisfies both

CAA and APA rulemaking requirements

with respect to final interpretations of

the Act consistent with the guidance.

Further, NRDC alleges that EPA may not

alter interpretations of the

Administrator through SIP rulemaking

signed by the Regional Administrator.

However, the Administrator has

properly delegated the authority for SIP

rulemakings to the Regional

Administrators under Delegation 7-10

dated May 6, 1997, and section 301(a)(1)

of the Act. Thus, the Regional

Administrators are authorized to act for

the Administrator with respect to all

matters pertaining to SIP approvals,

including interpretations of the Act

relevant to a given SIP approval.

Comment: A commenter questions the

30% limit on voluntary measures,

arguing that this limit itself implicitly

acknowledges that such measures are

not approvable.

Response: EPA did not impose the 3%

limit because it believed the measures to

be suspect, but rather, as noted in the

VMEP guidance, based on the

innovative nature of the measures and

the agency's lack of experience both

1

8 Guidance on Incorporating Voluntary Mobile

Source Emission Reduction programs in State

Implementation Plans (SIPs), October 24, 1997.

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with implementation and calculating

appropriate credit for such measures.

Therefore, EPA created the 3% limit as

a policy matter, indicating in the

guidance that it did not think it would

be appropriate to approve a greater

percentage while the agency begins to

implement the program. EPA further

indicated that it would reassess the

limit after several years of experience

with the program. Since all VMEP

measures would be approved only with

enforceable state commitments to fill

any resultant shortfall, EPA felt

confident that including voluntary

programs up to 3% of required

emissions reductions in SIPs would not

jeopardize attainment and maintenance

goals during initial implementation

under the policy. Further, EPA did not

indicate that 3% of required emissions

reductions could be considered de

minimis, as the commenter implies.

EPA agrees with the commenter that it

should not conclude in advance that

any given percentage of emissions

reduction could be considered per se de

minimis for all areas and types of SIPs.

Any conclusion about the de minimis

nature of required emission reductions

should be made in light of the specific

circumstances of the areas and CAA

requirements at issue. Therefore, all of

the commenter's arguments relating to

the availability of a de minimis

exemption and the need for notice-andcomment rulemaking to effectuate it are

not relevant to EPA's approval of the

voluntary measures in the HG area SIP.

Comment: The record is insufficient

to support TNRCC's credit claims.

Response: EPA reviewed the

documentation submitted for each

measure of the VMEP. We found that for

each measure the documentation was

acceptable to demonstrate that the

criteria for approval were met for each

measure. For each measure the State

was able to show that the measure plus

the State commitment was quantifiable,

surplus, enforceable, permanent, and

adequately supported.

Comment: One commenter pointed

out that delays may result from

identifying and rectifying emissions

shortfalls.

Response: EPA acknowledges that

reductions will be somewhat delayed

where states must first monitor and

assess implementation and

subsequently implement corrections.

For this reason EPA indicated in the

VMEP guidance that states should fill

any shortfalls in a timely fashion. EPA

recently issued a companion voluntary

measures policy for stationary sources.

See, "Incorporating Voluntary

Stationary Source Emission Reduction

Programs Into State Implementation

Plans-FINAL POLICY," memorandum

and attachment dated website January

19, 2001, from John Seitz, Director of

the Office of Air Quality Planning and

Standards. In that policy EPA indicated

that where voluntary measures were

included in attainment or rate of

progress SIPs, any shortfalls would have

to be filled prior to the relevant

attainment or progress milestone date.

EPA believes this is an appropriate

interpretation of the requirement to fill

shortfalls in a timely fashion under the

VMEP policy.

Comment: EPA put forth different,

conflicting explanations for why VMEP

measures purportedly will meet the

enforceability requirements of section

110(a)(2) of the Act. In the DFW

proposed approval we say that the

measures will be enforced by the State,

whereas in the HGA proposed approval

we say that the voluntary measures will

be enforceable against the State.

Response: As discussed above, courts

have upheld the legal authority to

enforce state SIP commitments. The

language in the DFW notice was

intended to indicate that Texas was to

monitor and assess reductions

attributable to VMEP and, in case of a

shortfall, implement measures to offset

that shortfall. What is enforceable is the

commitment to see that reductions in an

amount equal to what is proposed in the

VMEP are achieved. Such enforcement

is also available against the State, but

not against the individual entities that

are implementing the voluntary

measures. Texas has made similar

commitments with respect to both

Dallas/Fort Worth and the HG area.

Comment: EPA improperly redefined

the subject of the enforceability

requirements of section 110(a)(2); that

what is enforceable against the State is

the commitment to monitor, assess, and

timely remedy a shortfall from

implementation of the measures.

Response: We agree that what is

enforceable against the State is the

commitment to monitor, assess and

timely remedy any shortfall to ensure

the claimed VMEP reductions are met.

We do not agree that this is improper

under the Act and have already cited

case law in support of this position.

Comment: One commenter

appreciated EPA's approval of the

VMEP and asked for the State's and

EPA's continued support.

Response: We appreciate the

commenters support. EPA will continue

to support the State's VMEP activities as

long as they are developed and

implemented in accordance with EPA's

October 24, 1997, Guidance on

Incorporating Voluntary Mobile Source

Emission Reduction Programs in State

Implementation Plans (SIPs) and the

responses to comments in this

rulemaking.

3. Comments on TCMs

Comment: The commenters stated

that the TCMs are inadequate and do

not satisfy the requirements of section

182(d)(1)(A) of the Act.

Response: Section 182(d)(1)(A) directs

the State to submit a SIP revision that

identifies and adopts specific

enforceable transportation control

strategies and TCMs to offset any growth

in emissions from growth in vehicle

miles traveled or number of vehicle

trips in severe nonattainment areas, and

to attain reduction in motor vehicle

emissions as necessary to meet

reasonable further progress and

attainment requirements of the Act. The

State submitted SIP revisions to the EPA

on August 25, 1997 and May 17, 2000

to address the VMT Offset provision, the

first required element under section

182(d)(1)(A). The EPA proposed

approval of these SIP revisions on July

10, 2001 (66 FR 35920, see also 66 FR

35903), and subsequently received

public comments. The EPA's final

approval action on this SIP, the VMT

Offset Plan, has been taken in a separate

concurrent Federal Register action that

discusses the emissions growth offset

element in detail.

That action also explains that EPA

believes it is appropriate to allow States

to separate the VMT Offset SIP into

three elements, each to be submitted at

different times: (1) The initial

requirement to submit TCMs that offset

growth in emissions; (2) the requirement

to comply within the 15 percent

periodic reduction requirement of the

Act; and (3) the requirement to comply

with the post-1996 periodic reduction

and attainment requirements of the Act.

Please see the concurrent VMT Offset

action referenced above for the first

element.

Today's action here satisfies the

second and third elements of section

182(d)(1)(A). EPA believes this SIP

action, including its TCMs,

demonstrates that the HG area will

achieve the required ROP and

attainment of the ozone NAAQS for the

reasons discussed in more detail

throughout this final action, and that the

SIP therefore satisfies the last two

elements.

D. Response to Comments on Post 1999

Rate of Progress Plans

Comment: Texas provided a comment

on EPA's December 1999 proposal

indicating the April 2000 SIP revision

will contain a commitment by the state

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to submit a full Post-99 ROP analysis by

12/31/00.

Response: Texas has fulfilled this

commitment. EPA is approving this

Post-99 ROP plan in this action.

Comment: The TNRCC ROP plan

should be revised to be consistent with

the budget. The required NOx reduction

for 2005-2007 should be more than the

6% (3%/year for the 2 year period)

figure included in Chapter 5.

Response: The EPA acknowledges

that the TNRCC has included a 2007

MVEB, which in conjunction with the

other measures in the plan will result in

more than 6% emission reduction. The

Rate of Progress requirement is to

achieve at a minimum 6% emission

reduction for the time period 2006-2007

as called for by section 182(b)(2) of the

Act. The requirement should remain

6%, setting the MVEB lower will only

result in more reductions than needed

to achieve the required ROP levels.

Comment: One commenter on the

December 1999 proposed approval/

proposed disapproval claims that the

plans fail to demonstrate emission

reductions of 3% per year over each 3-

year period between November 1999

and November 2002; and November

2002 and November 2005; and the 2-

year period between November 2005

and November 2007, as required by 42

U.S.C. section 7511a(c)(2)(B). The states

have not even attempted to demonstrate

compliance with these requirements,

and EPA has not proposed to find that

they have been met. The EPA has

absolutely no authority to waive the

statutory mandate for 3% annual

reductions. The statute does not allow

EPA to use the NOx SIP call or 126

orders as an excuse for waiving rate-ofprogress (ROP) deadlines. The statutory

ROP requirement is for emission

reductions-not ambient reductions.

Emission reductions in upwind states

do not waive the statutory requirement

for 3% annual emission reductions

within the downwind nonattainment

area.

Response: Under no condition is EPA

waiving the statutory requirement for

3% annual emission reductions. In

today's action we are approving Texas

Post-99 ROP plan as submitted

December 2000 and revised and

submitted in October 2001. As provided

in this EPA's final action on the ROP

plan Texas is relying on reductions of

NOx and VOC within the nonattainment

area for meeting the ROP requirement.

E. Response to Comments on

Administrative Record

Comment: A commenter could not

find support in the administrative

record for the following propositions:

The Shortfall

Proposition: Identified potential

measures can achieve an additional 56

tons/day NOx emissions reduction

without requiring additional limits on

highway construction.

Support: In Chapter 7, Texas

projected that the measures being

considered for adoption would address

the 56 tpd short fall. Examination of

these measures reveals that their

implementation would not result in

additional limitations on highway

construction. Further, the State has

provided a commitment that future

measures will not rely on limits on

highway construction.

Proposition: The State's cited ranges

of potential reductions from measures

being considered to address the shortfall

provide a "reasonable assurance" that

the State can meet its commitment to

submit adopted measures to fill the

shortfall; the State has identified

sufficient innovative programs and new

technologies such that it is reasonable to

believe that, in the aggregate, the

projected emission reductions from

these new programs and technologies

can be achieved and will fill the

shortfall and the measures to be

considered for adoption at the midcourse review can achieve the NOx

emissions reductions indicated on pp.

23-24 of the Technical Support

Document.

Support: Chapter 7 of the Texas SIP

discusses each of the measures and the

State's projected range of emission

reductions. The TSD in Section IV.F.

has further discussion of each of the

potential measures and information that

exists to support the projected emission

reductions.

SB5 and Incentive Programs

Proposition: Texas Emission

Reduction Plan (TERP) will provide 130

million dollars per year for incentive

programs to reduce emissions.

Support: This estimate was based on

fiscal estimates provided by the State

regarding the revenue that will be

available from the fees associated with

this bill. Chapter 7 of the adopted SIP

cites an estimate of 133 million dollars.

Proposition: Incentive programs in

SB5 can achieve more reductions than

the reductions that were projected to be

achieved by the accelerated purchase of

Tier II/III non-road diesel equipment

and the Heavy-duty Diesel Equipment

Operating Restrictions measure and can

contribute to reducing the shortfall.

Support: This is discussed at Section

IV.F. of the TSD.

Proposition: It can safely be assumed

that at least 45% of the SB5 funding for

clean up of diesel engines will go to the

HG area and TERP can reasonably be

expected to provide 40 million dollars/

year to the HG area for reducing

emissions from existing diesel

equipment.

Support: These assumptions were first

developed based on early discussions

with TNRCC. We understand as pointed

out by the commenter that only $24.7

million/year are currently being

planned for the HG area. As discussed

in our response to comment on this

issue, we believe this will still provide

sufficient funds to replace the emission

reductions from the morning

construction ban and Accelerated Tier

I/11. clearly, the priority of TNRCC and

the legislation is to preserve the HG and

Dallas/Fort Worth SIPs. to that end as

discussed in the comments on this

control strategy in section III.B.3, Texas

has the discretion to provide more

money, even more than 40 million, to

the HG area if necessary.

Proposition: Incentive programs in

SB5 can obtain emissions reductions

from existing diesel equipment at an

average cost on the order of $3,000-

5,000/ton.

Support: As stated in the TSD, this is

based on experience with California

programs. The actual experience of the

Carl Moyer Program is a cost

effectiveness of better than $3000/ton as

stated in "The Carl Moyer Memorial Air

Quality Standards Attainment Program

(The Carl Moyer Program) GuidelinesApproved Revision 2000, November 16,

2000 California Environmental

Protection Agency Air Resources

Board."

Proposition: The TERP program for

reducing emissions from diesel

equipment can achieve between 32 and

40 tons/day of emissions reductions in

the HG area.

Support: This is discussed in IV.F of

the TSD. It is also discussed in Chapter

7 of the adopted version of the Texas

SIP and in the responses to comments

in this action.

Proposition: The TERP's projected

emissions reductions that will be

substituted for the Tier II/III non-road

diesel equipment measure will achieve

12.2 tons/day. It is also discussed in

Chapter 7 of the adopted version of the

Texas SIP submitted in a letter dated

October 4, 2001.

Support: This is discussed in Section

IV.F of the TSD.

Growth Rates

Proposition: Projected growth rates

and emissions reductions from the

sources subject to the Tier 2 Vehicle

Emission Standards and Federal Low

Sulfur Gasoline, National Low Emitting

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Vehicle Standards, and Heavy-duty

Diesel Standards were calculated

correctly by the State.

Support: The procedures for

calculating the emissions from on-road

vehicles are documented in Chapter 3 of

the SIP. As discussed in Chapter 3,

these emissions are based on a report

that was included in Appendix G of the

November 1999 SIP revision. Chapter 3

discusses several refinements and

revisions to what was provided in the

November 1999 SIP. These were

discussed in Appendix A of the TSD

Section I.F.

Proposition: Growth rates and

emission reductions were correctly

projected by the State for sources

subject to the Federal Measures,

including on-road and off-road mobile

source measures and the Act Statutory

Requirements.

Support: On-road measures were

discussed in the previous proposition.

Off-road measures are also discussed in

I.F. of Appendix A of the TSD.

Proposition: The State has correctly

factored growth in emissions due to

population and economic growth.

Support: These are discussed in

Section I.G.4 of Appendix A of the TSD.

Settlement

Proposition: Additional controls at

uncontrolled grandfathered facilities in

East Texas, which are called for by

recent legislation, will offset the

increased emissions from utilities

pursuant to the settlement agreement.

Support: This issue is discussed in

Chapter 6 of the Texas SIP. EPA's

review is discussed in the TSD in

Section III.K of the TSD. The issue is

also discussed in the response to

comments regarding model inputs.

Proposition: Substitution of a portion

of the emissions reductions from the

new TERP measures for the modeled

Heavy-duty Diesel Equipment Operating

Restrictions along with the change in

the NOx point source measures are not

expected to increase the modeled ozone

reductions. Changes in the Heavy-duty

Diesel Equipment Operating

Restrictions and rules for utilities will

not "adversely affect the modeling

results" or "affect modeling results in a

way to increase ozone."

Support: These issues were discussed

in III. I. of the TSD and in Chapter 7 of

the adopted SIP revision.

Speed Limit Reductions

Proposition: Reductions in the speed

limit to 55 mph in the HG area will

result in the reductions calculated by

TTI. The percentage of motorists that

TTI projected to exceed the newly

proposed speed limits is reasonable.

Support: The reduction in speed limit

is discussed in detail in TNRCC's SIP

and in particular in the State's response

to comments in the December 2000 SIP.

EPA reviewed and evaluated these

documents to draw these conclusions.

Also, se the Chapter 3 of the December

2000 SIP and Appendix A of the TSD.

RACM

Proposition: Texas has established

that all reasonable measures that could

accelerate the attainment date have been

adopted, or will be adopted.

Support: Chapter 7 of the SIP and

Appendix B of the TSD extensively

discuss this issue.

VOCs

Proposition: The modeling and list of

control measures demonstrate that

additional VOC controls are not costeffective in reducing ozone in the HG

area and would not advance the

attainment deadline.

Support: This issue is extensively

discussed in Appendix B. of the TSD

and Chapter 7 of the SIP. This issue is

discussed further in our response to

comments on this action.

Proposition: RACT is in place for all

major sources of VOC in the HG area.

Support: As part of our action

approving VOC requirements, we found

that the State had adopted RACT for all

major sources, in the HG area except

those that were to be covered by postenactment Control Technique

Guidelines (CTG's)(60 FR 12437, March

7, 1995). Since that time many expected

CTGs were issued as Alternative Control

Technique documents-ACTs. Of the

expected CTGs and ACTs, the HG area

had major sources in the following

categories; batch processing, industrial

wastewater, reactors and distillation,

and wood furniture. We have approved

measures for all of these categories as

meeting RACT.

Batch Processing-July 16, 2001 66 FR

36913

Industrial Wastewater-December 10,

2000 65 FR 79745

Reactors and Distillation-January 26,

1999, 64 FR 3841

Wood Furniture-October 30, 1996, 61

FR 55894

State's Estimated NOx Reductions

Proposition: The State control

measures and local initiatives will

provide the NOx reductions indicated in

Table 4 of the TSD. The State's

projection of expected emissions

reductions from Regional and Local

Measures is correct (this includes the

adequacy of the equivalent NOx

reductions credited to the commercial

lawn care shift). The NOx reductions for

the 2007 attainment year resulting from

the State control measures and local

initiatives predicted in Table 4 on pg. 18

of the TSD are accurate.

Support: First, each of the control

measures have been approved in

separate actions or in this action as

listed in Section II of this action. These

Federal Register actions announce our

belief that these are permanent,

enforceable measures that will achieve

emission reductions toward attainment.

Regarding the projected emission

reductions from each measure:

Point Source Control reductions are

well documented in a table in the

State's preamble to NOx rules submitted

in December 2000. We reviewed this

table in concluding the SIP will achieve

the projected reductions from point

sources. Also see the EPA's TSDs for its

actions on the point source rule and this

action.

The record for reductions for on-road

emissions reductions from I/M, low

emissions diesel fuel, speed limit

reductions, and vehicle idling are

discussed in previous propositions.

They are principally discussed in the

record in Chapter 3 of the SIP and in

Appendix A of the TSD.

Off-road measures; Heavy duty diesel

operating restriction and Accelerated

Tier II/III have been replaced by the

TERP and the potential emission

reductions from the TERP are discussed

in section IV.F. of the TSD. The

emissions shifted by small spark

operating restrictions are discussed in

the State's preamble to the rule and in

Chapter 6. Airport GSE emissions are

discussed in Appendix A of the TNRCC

December 2000 SIP submission, Heavy

equipment gas engines emission

reductions are discussed in the State's

preamble to the rules submitted in

December 2000.

Gas-fired water heaters-EPA

reviewed the discussion provided in the

State's preamble to the water heater and

small boiler rule.

VMEP measures and the projected

emission reductions are extensively

discussed in Appendix K of the

December 2000 State submission and in

section IV of the TSD.

Energy Efficiency projections are

discussed in Chapter 6 of the SIP.

Transportation Control Measure are

documented in Appendix I of the SIP

and discussed in section IV of the TSD.

IV. Administrative Requirements

Under Executive Order 12866 (58 FR

51735, October 4, 1993), this 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

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subject to Executive Order 13211,

"Actions Concerning Regulations That

Significantly Affect Energy Supply,

Distribution, or Use" (66 FR 28355, May

22, 2001). This action merely approves

state law as meeting Federal

requirements and imposes no additional

requirements beyond those imposed by

state law. Accordingly, the

Administrator certifies that this 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 approves 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

(Pub. L. 104-4).

This 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

approves a state rule implementing a

Federal standard, and does not alter the

relationship or the distribution of power

and responsibilities established in the

Act. This 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 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 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 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.).

The Congressional Review Act, 5

U.S.C. section 801 et seq., as added by

the Small Business Regulatory

Enforcement Fairness Act of 1996,

generally provides that before a rule

may take effect, the agency

promulgating the rule must submit a

rule report, which includes a copy of

the rule, to each House of the Congress

and to the Comptroller General of the

United States. EPA will submit a report

containing this rule and other required

information to the U.S. Senate, the U.S.

House of Representatives, and the

Comptroller General of the United

States prior to publication of the rule in

the Federal Register. A major rule

cannot take effect until 60 days after it

is published in the Federal Register.

This action is not a "major rule" as

defined by 5 U.S.C. section 804(2).

Under section 307(b)(1) of the Act,

petitions for judicial review of this

action must be filed in the United States

Court of Appeals for the appropriate

circuit by January 14, 2002. Filing a

petition for reconsideration by the

Administrator of this final rule does not

affect the finality of this rule for the

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).)

List of Subjects in 40 CFR Part 52

Environmental protection, Air

pollution control, Attainment,

Hydrocarbons, Nitrogen oxides, Ozone,

Incorporation by reference, Reporting

and recordkeeping requirements.

Dated: October 15, 2001

Gregg A. Cooke,

Regional Administrator, Region 6.

Part 52, chapter I, title 40 of the 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 et seq.

Subpart SS-Texas

2. In § 52.2270, entries in the "EPA

Approved Nonregulatory Provisions and

Quasi-Regulatory Measures in the Texas

SIP" table in paragraph (e) are added to

the end of the table to read as follows:

§52.2270 Identification of plan. * * * * *

(e) * * *

EPA APPROVED NONREGULATORY PROVISIONS AND QUASI-REGULATORY MEASURES IN THE TEXAS SIP

State subName of SIP provision Applicable geographic or mittal/effec- EPA approval date Comments nonattainment areadate

Attainment Demonstration for the 1-hour

Ozone NAAQS.

Speed Lim it Reduction ...................................

Voluntary Mobile Emission Program .............

Texas S enate B ill 5 ........................................

Houston/Galveston, TX .........

Houston/Galveston, TX .........

Houston/Galveston, TX .........

Houston/Galveston, TX .........

Transportation Control Measures Appendix I Houston/Galveston, TX .........

Commitment to Mid-course review ................ Houston/Galveston, TX .........

112/09/00

12/09/00

12/09/00

9/26/00

12/09/00

4/19/01

[Insert 11/14/01 Federal Register cite].

[Insert 11/14/01 Federal Register cite].

[Insert 11/14/01 Federal Register cite].

[Insert 11/14/01 Federal Register cite].

[Insert 11/14/01 Federal Register cite].

[Insert 11/14/01 Federal Register cite].

Section 6.3.12

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