Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58119 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[R06–OAR–2005–TX–0018; FRL–7980–6] 

Approval and Promulgation of Air 

Quality Implementation Plans; Texas; 

Revisions to the Ozone Attainment 

Plan for the Houston/Galveston/ 

Brazoria Nonattainment Area 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: EPA is proposing to approve 

revisions to the State Implementation 

Plan (SIP) for the State of Texas as it 

applies to the Houston/Galveston/ 

Brazoria (HGB) Ozone nonattainment 

area. These plan revisions result from 

more recent information on ozone 

formation in the Houston/Galveston 

area indicating that a combination of 

controls on oxides of Nitrogen (NOX) 

and highly reactive volatile organic 

compounds (HRVOCs) should be more 

effective in reducing ozone than the 

measures in the previously approved 

plan which relied almost exclusively on 

control of NOX. Approval of these 

revisions will incorporate these changes 

into the federally approved SIP. 

DATES: Comments must be received on 

or before November 4, 2005. 

ADDRESSES: Submit your comments, 

identified by Regional Material in 

EDocket (RME) ID No. R06–OAR–2005–

TX–0018, by one of the following 

methods: 

• Federal eRulemaking Portal: http:// 

www.regulations.gov. Follow the on-line 

instructions for submitting comments. 

• Agency Web site: http:// 

docket.epa.gov/rmepub/ Regional 

Material in EDocket (RME), EPA’s 

electronic public docket and comment 

system, is EPA’s preferred method for 

receiving comments. Once in the 

system, select ‘‘quick search,’’ then key 

in the appropriate RME Docket 

identification number. Follow the online instructions for submitting 

comments. 

• U.S. EPA Region 6 ‘‘Contact Us’’

Web site: http://epa.gov/region6/ 

r6coment.htm Please click on ‘‘6PD’’

(Multimedia) and select ‘‘Air’’ before 

submitting comments. 

• E-mail: Mr. Thomas Diggs at 

diggs.thomas@epa.gov. Please also cc 

the person listed in the FOR FURTHER

INFORMATION CONTACT section below. 

• Fax: Mr. Thomas Diggs, Chief, Air 

Planning Section (6PD–L), at fax 

number 214–665–7263. 

• Mail: Mr. Thomas Diggs, Chief, Air 

Planning Section (6PD–L), 

Environmental Protection Agency, 1445 

Ross Avenue, Suite 1200, Dallas, Texas 

75202–2733. 

• Hand or Courier Delivery: Mr. 

Thomas Diggs, Chief, Air Planning 

Section (6PD–L), Environmental 

Protection Agency, 1445 Ross Avenue, 

Suite 1200, Dallas, Texas 75202–2733. 

Such deliveries are accepted only 

between the hours of 8 am and 4 pm 

weekdays except for legal holidays. 

Special arrangements should be made 

for deliveries of boxed information. 

Instructions: Direct your comments to 

Regional Material in EDocket (RME) ID 

No. R06–OAR–2005–ST–0018. EPA’s 

policy is that all comments received 

will be included in the public file 

without change, and may be made 

available online at http:// 

docket.epa.gov/rmepub/, including any 

personal information provided, unless 

the comment includes information 

claimed to be Confidential Business 

Information (CBI) or other information 

the disclosure of which is restricted by 

statute. Do not submit information 

through Regional Material in EDocket 

(RME), regulations.gov, or e-mail if you 

believe that it is CBI or otherwise 

protected from disclosure. The EPA 

RME website and the Federal 

regulations.gov are ‘‘anonymous access’’

systems, which means EPA will not 

know your identity or contact 

information unless you provide it in the 

body of your comment. If you send an 

e-mail comment directly to EPA without 

going through RME or regulations.gov, 

your e-mail address will be 

automatically captured and included as 

part of the comment that is placed in the 

public file and made available on the 

Internet. If you submit an electronic 

comment, EPA recommends that you 

include your name and other contact 

information in the body of your 

comment and with any disk or CD–ROM 

you submit. If EPA cannot read your 

comment due to technical difficulties 

and cannot contact you for clarification, 

EPA may not be able to consider your 

comment. Electronic files should avoid 

the use of special characters, any form 

of encryption, and be free of any defects 

or viruses. 

Docket: All documents in the 

electronic docket are listed in the 

Regional Material in EDocket (RME) 

index at http://docket.epa.gov/rmepub/. 

Although listed in the index, some 

information is not publicly available, 

i.e., CBI or other information whose 

disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the Internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available either electronically in RME or 

in the official file which is available at 

the Air Planning Section (6PD–L), 

Environmental Protection Agency, 1445 

Ross Avenue, Suite 700, Dallas, Texas 

75202–2733. The file will be made 

available by appointment for public 

inspection in the Region 6 FOIA Review 

Room between the hours of 8:30 am and 

4:30 pm weekdays except for legal 

holidays. Contact the person listed in 

the FOR FURTHER INFORMATION CONTACT

paragraph below or Mr. Bill Deese at 

(214) 665–7253 to make an 

appointment. If possible, please make 

the appointment at least two working 

days in advance of your visit. There will 

be a 15 cent per page fee for making 

photocopies of documents. On the day 

of the visit, please check in at the EPA 

Region 6 reception area at 1445 Ross 

Avenue, Suite 700, Dallas, Texas. 

The State submittal is also available 

for public inspection at the State Air 

Agency listed below during official 

business hours by appointment: Texas 

Commission on Environmental Quality, 

Office of Air Quality, 12124 Park 35 

Circle, Austin, Texas 78753. 

FOR FURTHER INFORMATION CONTACT: Guy 

R. Donaldson, Air Planning Section 

(6PD–L), Environmental Protection 

Agency, Region 6, 1445 Ross Avenue, 

Suite 700, Dallas, Texas 75202–2733, 

telephone (214) 665–7242 fax number 

214–665–7263; e-mail address 

donaldson.guy@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Throughout this document wherever 

‘‘we,’’ ‘‘us,’’ or ‘‘our’’ is used, we mean 

the EPA. 

Table of Contents 

I. Background 

A. What Are the Actions Being Proposed 

Here? 

B. Why Control Ozone? 

C. What Does the Currently Approved SIP 

for HGB Contain? 

D. What Revisions to State Implementation 

Plan Are Being Considered Here? 

E. What General Criteria Must These 

Revisions Meet To Be Approvable? 

II. Evaluation 

A. One Hour Attainment Demonstration 

1. What Modeling Approaches Were Used 

for This Attainment Demonstration? 

2. What Is a Photochemical Grid Model? 

3. What Episode Did Texas Choose To 

Model? 

4. How Well Did the Model perform? 

5. What Did the Results of Modeling 

Routine Emissions Show? 

6. What Did the Results of the Emission 

Event Modeling Show? 

7. How Did Texas Handle Questions About 

Emission Estimates? 

8. What Actions Are Being Taken To 

Improve Emissions Estimates of 

HRVOCs? 

9. What About Estimates of Less-Reactive 

VOC Emissions? 

58120 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

10. What Additional Evidence Did Texas 

Provide? 

11. Is the One-Hour Attainment 

Demonstration Approvable? 

B. New Control Measures 

1. What Are the New Control Measures in 

these SIP revisions? 

2. What Are the Annual Cap and ShortTerm Limit on HRVOC Emissions? 

3. How Are Annual Cap and Short-Term 

Limits Related? 

4. Can Reductions in Less-Reactive VOCs 

Be Made Instead of Reductions in 

HRVOCs? 

5. What Estimates of Flare Efficiency Are 

Made in the SIP Revision? 

6. How Has the Texas Leak Detection and 

Repair Program Been Strengthened? 

7. How Have the Benefits of the Leak 

Detection and Repair Program Been 

Projected? 

8. What Are the Requirements for Portable 

Gasoline Containers? 

C. Revised Control Measures 

1. What Control Measures Have Been 

Revised or Repealed? 

D. Reasonably Available Control Measures 

1. What Are the RACM Requirements? 

2. How Has Texas Insured With This Plan 

Revision That all RACM are Being 

Implemented? 

E. Section 110(l) Analysis 

1. What Does Section 110(l) Require? 

2. How Has Texas Shown These Revisions 

Do Not Interfere With Attainment of the 

8-Hour Standard? 

3. What About Possible Interference With 

the 1-Hour Ozone Standard? 

4. How Has Texas Shown These Revisions 

do not Interfere With Rate of Progress? 

5. Do These Revisions Interfere With 

Attainment of other Standards Besides 

Ozone? 

6. Do the Revisions Interfere With any 

Other Applicable Requirements of the 

Act? 

F. Enforceable Commitments 

1. What Is an Enforceable Commitment? 

2. What Were the Enforceable 

Commitments in the 2001 Approved SIP 

and Have They Been Fulfilled? 

G. Motor Vehicle Emissions Budgets 

1. What Is a Motor Vehicle Emissions 

Budget and Why Is it Important? 

2. What Are the Motor Vehicle Emissions 

Budgets Being Proposed for Approval? 

III. Statutory and Executive Order Reviews 

I. Background 

A. What Are the Actions Being Proposed 

Here? 

EPA is proposing to approve the 

following revisions to the approved 1- 

hour ozone attainment plan for the HGB 

area: 

• TCEQ’s revised demonstration, 

submitted December 2004, that the 1- 

hour ozone standard will be achieved in 

2007. 

• The revised motor vehicle 

emissions budgets associated with the 

revised attainment demonstration. 

• TCEQ’s revised demonstration that 

all reasonably available control 

measures have been adopted for the 

HGB area. 

• Revisions to satisfy the enforceable 

commitments contained in the 

previously approved SIP (November 

2001, 66 FR 57160). With respect to its 

original enforceable commitment to 

reduce NOX emissions, TCEQ has 

instead substituted reductions in 

HRVOCs for a portion of these NOX

reductions and shown that the HRVOC 

reductions are as effective in reducing 

ozone levels. 

• Revisions to the industrial NOX

rules submitted January 2003, which 

included several miscellaneous changes 

and the reduction in stringency from a 

nominal 90% to 80% control. 

• Revisions to the Texas Inspection 

and Maintenance (I/M) rules that drop 

three counties from the I/M program. In 

addition, several miscellaneous changes 

are proposed for approval. 

• Repeal of the vehicle idling rule. 

• Repeal of the Small Spark Engine 

Operating Restrictions. 

• Revisions to the Speed Limit 

Strategy. 

• Revisions to the voluntary mobile 

emissions program (VMEP). 

To replace the above measures being 

repealed or relaxed, Texas has adopted 

the following new control measures: 

• Annual Cap on HRVOC emissions. 

• Hourly (short-term) limit on 

HRVOC emissions. 

• Improved requirements for HRVOC 

fugitive emissions. 

• Requirements for Portable Gasoline 

containers. 

Separately, EPA has proposed or is 

proposing to approve the newly adopted 

measures. Comments on the proposed 

approval of the new control measures 

should be directed to these separate 

Federal Register actions. The actions 

addressed in this rulemaking in 

conjunction with the new HRVOC rules, 

if approved, will provide for timely 

attainment as demonstrated through the 

modeling analysis. In addition, Texas 

has shown that these revisions will not 

interfere with any applicable 

requirement concerning attainment and 

reasonable further progress, or any other 

applicable requirement of this Act. 

(Section 110(l) demonstration). 

B. Why Control Ozone? 

Inhaling even low levels of ozone can 

trigger a variety of health problems 

including chest pains, coughing, nausea, 

throat irritation, and congestion. It can 

also worsen bronchitis and asthma and 

reduce lung capacity. EPA has 

established National Ambient Air 

Quality Standards (NAAQS) for ozone. 

The standard of 0.12 ppm averaged over 

a 1-hour period was adopted in 1979. In 

July 1997, EPA adopted a revised 

standard of 0.08 ppm averaged over an 

8-hour period. In the Phase I 

Implementation Rule (April 30, 2005, 69 

FR 23951) for the 8-hour standard, EPA 

provided for revocation of the 1-hour 

standard for most areas including HGB 

on June 15, 2005. Also, EPA established 

anti-backsliding provisions to insure 

that areas maintain the progress 

expected under the requirements of the 

1-hour standard as areas transition to 

developing programs to meet the 8-hour 

standard. 

C. What Does the Currently Approved 

SIP for HGB Contain? 

On November 14, 2001, EPA 

approved the 1-hour ozone attainment 

plan for the HGB nonattainment area. 

This plan relied primarily on reductions 

in emissions of NOX to project 

attainment. The plan included a wide 

variety of controls on NOX emissions 

including an approximately 90% 

reduction in industrial NOX emissions, 

vehicle inspection and maintenance in 

eight counties, and the Texas Emission 

Reduction Program (TERP). The plan, 

however, did not contain sufficient 

adopted control measures as needed to 

demonstrate attainment. Because the 

State had adopted NOX measures more 

stringent than any where else in the 

country and was unable to identify 

specific NOX measures by which to 

achieve all of the needed emission 

reductions, the State included an 

enforceable commitment to adopt rules 

to achieve the 56 tpd of additional 

emission reductions which were 

necessary to demonstrate attainment. 

The additional measures were to be 

adopted in two phases; measures to 

achieve 25% of the needed reductions 

were to be adopted by December 2002 

with measures to achieve the remaining 

emission reductions to be adopted by 

May 2004. In addition, Texas committed 

to perform a mid-course review, 

evaluating the modeling, inventory data 

and other tools and assumptions used to 

develop the plan and make adjustments 

to the plan to provide for timely and 

cost effective attainment. If, based on 

the mid-course review, more or fewer 

NOX reductions were necessary, Texas 

committed to provide the revised 

analysis to EPA for review. 

Texas, however, was sued in State 

court on its plan for the Houston area. 

The litigants alleged that the controls on 

industrial NOX emissions of 

approximately 90% would not be 

effective and that instead the State 

should be controlling releases of 

HRVOCs. Texas entered into a 

settlement agreement with the litigants 

whereby one facet of the mid-course 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58121 

1 In addition, EPA has retained the 1-hour 

attainment demonstration requirement as an 

applicable requirement under the Phase I rules 

antibacksliding provisions. See 40 CFR 51.900(f). 

review was accelerated to determine if 

the point source NOX controls could be 

relaxed and replaced with controls on 

HRVOCs. This study and any 

consequent rule changes were to be 

completed by December 2002. 

D. What Revisions to the State 

Implementation Plan Are Being 

Considered Here? 

The following submissions which 

impact the HGB attainment plan are 

being considered : 

January 28, 2003: This submission 

responded to the State’s settlement 

agreement to provide an accelerated 

evaluation of whether the industrial 

NOX controls could be relaxed and 

controls on HRVOCs could be 

substituted. Based on the study, the 

commission adopted relaxed controls on 

NOX emissions from industrial sources 

and new controls on HRVOCs. Texas 

also adopted a number of minor 

revisions to the general VOC rules. 

Finally, the State also provided a 

demonstration that TERP emission 

reductions would be sufficient to 

achieve the 25% of the NOX reductions 

needed to demonstrate attainment (i.e., 

about 14 tpd). 

October 16, 2003: This submission 

delayed compliance for the I/M program 

in Chambers, Liberty and Waller 

Counties. (RME R06–OAR–2005–TX–

0035) 

October 6, 2004: This submission 

repealed the I/M program in Chambers, 

Liberty and Waller Counties.(RME R06- 

OAR–2005-TX–0035) 

November 16, 2004: This submission 

repealed a ban on morning operations of 

lawn service contractors. 

December 17, 2004: This submission 

was submitted to meet the State’s 

commitment to provide a mid-course 

review SIP. Based on the updated 

analysis, the State further tightened 

controls on HRVOCs in Harris county 

and revised or repealed a number of 

NOX control measures including, the 

vehicle idling prohibition (Docket R06–

OAR–2005–TX–0013), the speed limit 

strategy, the voluntary mobile emissions 

program (VMEP) and the commitment to 

achieve NOX reductions reductions 

beyond the initial 25% provided in 

January 2003 (i.e., revoked the State’s 

commitment to achieve 42 tpd of the 

NOX reductions that were included in 

the enforceable commitment as part of 

the prior attainment demonstration). 

E. What General Criteria Must These 

Revisions Meet To Be Approvable? 

To be approved, the revisions to the 

attainment demonstration must meet 

several requirements. First, the State 

submission must demonstrate that the 

revised plan, as a whole, will result in 

attainment of the 1-hour as 

expeditiously as practicable but no later 

than 2007. This is necessary, even 

though the 1-hour standard was revoked 

on June 15, 2005, because the approved 

SIP commits the State to adopt 56 tons/ 

day of additional NOX reductions 

unless, based on the mid-course review 

analysis, the area can show attainment 

of the 1-hour standard by 2007 with a 

different mix of emission reductions.1 In 

Section II.A. we discuss TCEQ’s revised 

1-hour attainment demonstration. 

Second, the measures in the revised 

control strategy must meet the 

requirements for being creditable under 

the Clean Air Act and must be 

permanent, surplus, quantifiable and 

enforceable and achieve the necessary 

amount of reductions. The new and 

revised measures are discussed in 

Section II.B. and II.C. Some of these 

control measures have been or are being 

reviewed in separately proposed rules. 

Before the revisions to the attainment 

plan can be finally approved, all of the 

control measures relied on in the 

attainment plan must also be approved. 

Third, the State must show that the 

revised control strategy includes all 

reasonably available control measures 

(RACM). This showing is discussed in 

Section II.D. Fourth, the State must 

show, as required by section 110(l) of 

the Clean Air Act, that the revisions to 

the plan will not interfere with 

attainment or reasonable further 

progress or any other applicable 

requirement of the Act. Compliance 

with 110(l) is discussed in Section II.E. 

Finally, the State must show that it has 

met all of the enforceable commitments 

contained in the approved SIP. (Instead 

of meeting the enforceable commitment 

to achieve the remaining 42 tpd NOX

reductions, the State has adopted 

controls on HRVOCs and submitted 

modeling to demonstrate that the 42 

tons/day of NOX reductions is not 

necessary for the HGB area to attain by 

November 2007.) Enforceable 

commitments are discussed in Section 

II.F. 

II. Evaluation 

A. One Hour Attainment Demonstration 

1. What Modeling Approaches Were 

Used for This Attainment 

Demonstration? 

As required by the Clean Air Act, 

Texas has used photochemical grid 

modeling in its demonstration that the 

control strategy for the HGB area will 

achieve attainment by 2007. Also, as 

allowed under EPA policy, TCEQ has 

introduced other evidence, referred to as 

weight of evidence, to supplement the 

modeling analysis. The modeling 

provided in the mid-course review SIP 

revision builds on modeling performed 

for the January 2003 SIP revision which 

TCEQ submitted in support of reducing 

the stringency of the industrial NOX

rules and adopting measures for the 

control of HRVOCs. 

The SIP revision actually relies on 

two sets of modeling analyses. First, the 

SIP relies on modeling performed by the 

TCEQ that is intended to simulate the 

routine emissions that occur in the HGB 

area and determine the level of routine 

emissions that can be allowed in the 

area to provide for attainment. Second, 

the SIP relies on modeling that was 

provided through a collaborative effort 

(known as project H13) of the Houston 

Advanced Research Center, the TCEQ, 

the University of Texas and the 

University of North Carolina. The 

project H13 report was entitled, 

‘‘Variable Industrial VOC Emissions and 

Their Impact on Ozone Formation in the 

Houston Galveston Area,’’ April 16, 

2004. This second modeling effort was 

used to estimate the impact of nonroutine emission events on ozone levels. 

This two pronged approach is consistent 

with observations that indicate that 

Houston’s air quality problems stem 

from the combination of two 

phenomena, normal routine emissions 

and large non-routine releases of 

HRVOC emissions. For a more complete 

description of the modeling procedures 

and EPA’s evaluation of these 

procedures, see the Technical Support 

Document (TSD) in the Docket for this 

action (RO6–OAR–2005–TX–0018). 

2. What Is a Photochemical Grid Model? 

Photochemical grid models are the 

state-of-the-art method for predicting 

the effectiveness of control strategies in 

reducing ozone levels. The model uses 

a three-dimensional grid to represent 

conditions in the area of interest. In this 

case, TCEQ has developed a grid system 

that stretches from beyond Austin to the 

west, to Georgia to the east, to Nebraska 

to the north and into the Gulf of Mexico 

to the south. The model uses nested grid 

cells of 36 km on the outer portions, 12 

km in east Texas and portions of nearby 

States and a 4 kilometer grid cell 

covering the HGB and Beaumont Port 

Arthur (BPA) areas. For more 

information on the modeling domain, 

please see the TSD. The model 

simulates the movement of air and 

emissions into and out of the threedimensional grid cells (advection and 

58122 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

2These values also do not include the impact of 

wildfires as discussed in the WOE section. 

dispersion); mixes pollutants upward 

and downward among layers; injects 

new emissions from sources such as 

point, area, mobile (both on-road and 

nonroad), and biogenic into each cell; 

and uses chemical reaction equations to 

calculate ozone concentrations based on 

the concentration of ozone precursors 

and incoming solar radiation within 

each cell. 

Air quality planners choose an 

historical episode of high ozone levels 

to apply the model. Running the model 

requires large amounts of data inputs 

regarding the emissions and 

meteorological conditions during an 

episode. Modeling to duplicate 

conditions during an historical episode 

is referred to as the base case modeling 

and is used to verify that the model 

system can predict the historical ozone 

levels with an acceptable degree of 

accuracy. If the model can predict the 

ozone levels in the base case, it can then 

be used to project the response of future 

ozone levels to proposed emission 

control strategies. 

3. What Episode Did Texas Choose To 

Model? 

Texas chose an historical episode, 

August 19–September 6, 2000, that 

encompassed the time period of the 

Texas Air Quality Study (TxAQS) 2000. 

During this study, researchers from 

around the country participated in an 

intensive study of ozone formation in 

the HGB area, collecting additional 

meteorological and chemical data. This 

study has provided a wealth of 

information to test the assumptions in 

the model. EPA believes that the 

extended episode from August 19–

September 6, 2000, is an acceptable 

episode for development of the 1-hour 

attainment plan. It encompasses 13 

exceedance days and contains a variety 

of meteorological conditions which 

resulted in high concentrations of ozone 

in the area as measured on both a 1-hour 

and 8-hour basis. 

4. How Well did the Model Perform? 

Model performance is a term used to 

describe how well the model predicts 

the ozone levels in an historical 

episode. As models have to make 

numerous simplifying assumptions and 

the system being modeled is very 

complex, model predictions will never 

be perfect. EPA has developed various 

diagnostic, statistical and graphical 

analyses that TCEQ has performed to 

evaluate the model’s performance and 

determine if the model is working 

adequately to test control strategies. For 

a subset of days, August 25, 26, 29, 30, 

31, September 1–4 and 6, TCEQ deemed 

the model’s performance adequate for 

control strategy development to address 

routine emissions. EPA agrees that the 

overall model performance is adequate 

but notes that the model tends to underpredict on high days and over-predict 

on low days raising some uncertainty in 

the control strategy modeling. At least 

part of the under prediction has been 

attributed to non-routine emissions not 

captured in the modeling. This is 

discussed further in the section on 

alternative design values. It is also 

worth noting that, to achieve adequate 

performance, TCEQ adjusted the 

amount of HRVOC emissions in the 

model above the reported emission 

inventory values based on ambient 

measurements which demonstrated that 

reported HRVOC emissions were 

underestimated. This adjustment is 

discussed in more detail in later 

sections. 

5. What Did the Results of the Modeling 

of Routine Emissions Show? 

The results of modeling the revised 

control strategy are shown in Table 1. 

Episode day Measured peak Modeled peak 

(base case) 

Modeled peak 

(future case 2) 

August 25 ....................................................................................................................... 194 156.5 121.6 

August 26 ....................................................................................................................... 140 149.4 113.6 

August 29 ....................................................................................................................... 146 .7 151.2 113.6 

August 30 ....................................................................................................................... 200 .5 137.2 122.5 

August 31 ....................................................................................................................... 175 .5 173.0 147.6 

September 1 .................................................................................................................. 163 .7 136.7 119.5 

September 2 .................................................................................................................. 125 .5 152.7 128.6 

September 3 .................................................................................................................. 127 .2 139.3 115.0 

September 4 .................................................................................................................. 145 .0 158.0 125.2 

September 6 .................................................................................................................. 156 .0 152.9 125.1 

Table 1 shows that on all of the days 

except August 31, the modeled control 

strategy was predicted to bring the area 

under or very near the one-hour 

standard of 125 ppb. The modeling, 

however, incorporates only routine 

emissions in the future case and 

reported non-routine emissions in the 

base case. As will be discussed in more 

detail in later sections, TCEQ believes 

that large non-routine emission events 

not included in the modeling also 

contribute to high ozone levels in the 

HGB area. These non-routine emission 

events explain, in part, the model’s 

under-prediction on several days such 

as August 25th, 30th, and September 

1st. 

As discussed in the weight of 

evidence section regarding alternative 

design values, the TCEQ believes that 

without the influence of emission 

events, an alternative design value of 

144 ppb can be estimated. If 144 ppb is 

a reasonable representation of the area’s 

ozone levels due to routine emissions, 

then the modeling results in Table 1 

indicate sufficient reductions in ozone 

levels due to routine events. In addition 

to the modeling results and the 

alternative design value approach which 

is explained later in this notice, TCEQ 

has presented other evidence to 

demonstrate that attainment will be 

reached. These additional 

demonstrations are included in the 

weight of evidence section. 

To address the part of the ozone levels 

due to non-routine emissions, TCEQ 

established a short term limit of 1200 lb/ 

hr on emissions of HRVOCs. The 

development of this limit is discussed 

in the next section on emission event 

modeling. The purpose of this limit is 

to reduce the frequency of non-routine 

emission events sufficiently so that 

emission events impacting peak ozone 

levels will be reduced in frequency to 

less than 1 event per year and thus will 

not impact attainment of the 1-hour 

standard. 

We recognize that there is 

considerable uncertainty regarding the 

impact of emission events on peak 

ozone. As we discuss in the next section 

on emission event modeling, the project 

H13 study seems to indicate a smaller 

impact of emission events on peak 

ozone levels than the alternative design 

value approach. The projected smaller 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58123 

impact could stem from the following 

reasons. First, the H13 study looked at 

the impact of emission releases after the 

institution of NOX controls, whereas the 

alternative design value analysis 

performed by TCEQ is based on historic 

data before the institution of controls. 

Thus, the impact of emission events in 

the past is likely to be larger than events 

in the future when there is less NOX

with which to react. Second, the 

frequency of events was based only on 

detected and reported events. Past 

monitoring and reporting techniques 

may not have detected all events. The 

improved HRVOC reporting rules 

should help address this possible 

problem. Finally, project H13’s 

assumptions regarding the frequency of 

events looked only at events occurring 

at the most sensitive times and location. 

Larger events occurring at slightly less 

sensitive times and locations could also 

be impacting peak ozone. On the other 

hand, it is likely that the alternative 

design value approach overstates the 

impact of emission events. Some of the 

rapid rises in monitored ozone that are 

filtered out in the alternative design 

value approach could be caused by 

narrow continuous plumes of ozone 

sweeping across a monitor as winds 

shift direction. Weighing the available 

information, EPA believes that the 

occurrence of emission events in the 

HGB area that are not included in the 

model contribute at least in part to the 

model’s under prediction of some 

measured ozone levels. The short-term 

limit will address these non-routine 

emission events. In addition, the 

controls on routine emissions will 

provide the reductions in the ozone due 

to routine emissions necessary to reach 

attainment. In addition, Texas has 

considered other weight of evidence 

information indicating there will be 

more improvement in air quality than 

can be expected demonstrated by the 

modeling of routine emissions. 

6. What Did the Results of the Emission 

Event Modeling Show? 

Traditionally ozone control plans 

have been based on the assumption that 

emissions for an area do not change 

significantly from day to day and 

differences in pollution levels are 

caused by changes in the meteorological 

conditions between days. This 

assumption has been reexamined for the 

Houston area because of the number of 

non-routine emissions that are reported 

in the Houston area from the refining 

and petrochemical industry. 

The project H13 report, ‘‘Variable 

Industrial VOC Emissions and Their 

Impact on Ozone Formation in the 

Houston Galveston Area,’’ April 16, 

2004, looked at the potential impact of 

emission releases in the area. It 

determined, by examining the TCEQ 

emission events data base and records of 

emissions from sources with monitors 

on flares and cooling towers, that 

‘‘variability in HRVOC emissions from 

point sources is significant and due to 

both variability in continuous emissions 

and discrete emission events.’’ The area 

wide variability had the following 

characteristics:2–3 times per month 

HRVOC emissions variability > 10,000 

lbs/hour,2–3 times per month HRVOC 

emissions variability 5,000–10,000 lbs/ 

hour, daily HRVOC emissions 

variability > 100 lbs/hour. 

Based on the above findings, the 

researchers then examined the impact 

that emissions variability could have on 

peak ozone levels by modeling the 

impact of emission events of various 

sizes at various locations and times. It 

was determined that an event of 1,000 

lbs in the most sensitive area and during 

the most sensitive time could have a 1–

2 ppb impact on the peak ozone level 

within the fine grid modeling domain. 

Larger events would have 

correspondingly larger impacts on 

ozone levels. A 10,000 lb release at the 

most sensitive place could have a 10–20 

ppb impact on ozone levels. 

The study, based on assumptions 

regarding the frequency of ozone 

conducive weather conditions, the time 

window most sensitive to releases and 

the location of most sensitive releases, 

presented the results of a Monte Carlo 

simulation to estimate the probability 

and expected magnitude of emission 

events that would impact peak ozone 

levels. The report states that if no 

actions were taken to reduce emissions 

variability, an air quality plan should 

anticipate that at least one event per 

year of 1,000 lbs would happen at the 

right time and the right place to impact 

peak ozone. Based on this finding, 

TCEQ adopted a short-term limit on 

HRVOC emissions designed to reduce 

the magnitude and frequency of 

emissions events. This is not to say that 

a 1–2 ppb increase in ozone is not 

significant, but that with the short term 

limit, the occurrence of non-routine 

events at the times and places to impact 

peak ozone will be diminished 

sufficiently as not to impact attainment 

with the 1-hour ozone standard. 

Because facilities would be expected to 

take action to avoid events of 1,200 lbs/ 

hr, the frequency of such events in the 

future will be lower than in the past and 

therefore less than 1 event per year 

impacting peak ozone should be 

expected. As discussed, some nonroutine emissions, in the past, may not 

have been detected or reported in which 

case the actual frequency of events 

impacting peak ozone levels may be 

higher than projected in project H13, 

which as discussed previously, would 

help explain the under-prediction in the 

routine modeling. The improved 

monitoring requirements in chapter 115 

should serve to prevent undetected 

HRVOC releases in the future and the 

specter of enforcement will cause 

facilities to take measures to prevent 

emission events. This is further 

discussed in the section on the short 

term and long term cap. 

7. How Did Texas Handle Questions 

About Emission Estimates? 

TCEQ has followed acceptable 

procedures for the development of the 

base case inventory, following or 

building upon EPA guidance. Despite 

these efforts, one of the findings of the 

TexAQS 2000 study was that observed 

concentrations of certain compounds, 

especially light olefins such as ethylene 

and propylene, were much larger than 

represented in the reported emission 

inventory. This conclusion has been 

reviewed and documented in numerous 

scientific journals. For more information 

on these studies see the TSD. 

Emissions of these compounds 

principally come from the 

petrochemical industry. While it is clear 

that the reported emissions are too low, 

the ambient data does not show, 

however, which types of facilities and 

equipment are the source of the 

underestimated emissions. Various 

methods have been attempted to 

estimate the actual emissions of VOCs 

in the HGB area based on the available 

ambient measurements. TCEQ decided 

to use data from aircraft flights which 

indicated NOX emissions were similar 

to VOC emissions when considered on 

a molar basis. Therefore, TCEQ adjusted 

the molar emission rate of HRVOC 

emissions at each facility to match the 

NOX emission rate. This adjustment is 

more fully described in Chapter 3 of the 

SIP revision. The adjustment had the 

effect of substantially increasing the 

level of HRVOC emissions in the 

modeled emissions inventory. Prior to 

adjusting the inventory, the model did 

not perform well. Model performance 

was improved after the adjustment. The 

adjusted inventory became the basis for 

achieving acceptable model 

performance and for the control strategy 

development. 

Clearly, this type of across-the-board 

adjustment of emissions is not the 

preferable way to estimate emissions 

and makes control strategy targeting and 

development difficult. Unfortunately, 

using established methods for 

estimating source emissions has been 

58124 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

demonstrated to be inaccurate. As 

support for their adjustment approach, 

TCEQ points out the amount of 

emissions added to the inventory is 

corroborated by a study conducted by 

Environ ATop Down Evaluation of the 

Houston Emissions Inventory Using 

Inverse Modeling’’ (Yarwood et al., 

2003) which indicated that 

approximately the right amount of 

reactivity had been added to the model 

and that further adjustment was not 

warranted under the then-current model 

formulation. 

EPA believes that the approach Texas 

has taken to estimate the inventory of 

HRVOCs is acceptable given the 

information that is available. This 

conclusion is supported by the available 

aircraft data and Environ inverse 

modeling study. Clearly, this is an area 

that should be improved as the State 

develops future SIP revisions. 

8. What Actions Are Being Taken To 

Improve the Emissions Estimates of 

HRVOCs? 

It was the consensus at a conference 

of emissions inventory experts held in 

Clear Lake, Texas in 2001, that the 

errors in the inventory were most likely 

from errors in the estimates of emissions 

from cooling towers, flares, fugitive 

emissions and start-up, shutdown and 

malfunction events. Texas has moved 

forward to improve the inventory of 

HRVOCs in all of these areas by 

requiring monitoring of cooling towers, 

flares, pressure relief devices and 

process vents in HRVOC service. This 

source monitoring, which will be in 

place by the end of 2006, should 

dramatically reduce the amount of error 

in the HRVOC inventory by more 

directly measuring both continuous 

emissions and emissions events. In 

addition, for all VOCs, Texas is now 

requiring that correlation equations be 

used for the estimation of fugitive 

emissions. This will reduce the amount 

of error in fugitive emission estimates. 

9. What About Estimates of LessReactive VOC Emissions? 

Texas elected to adjust the reported 

emission rates of only HRVOCs. Other 

less-reactive chemicals are also released 

from flares, cooling towers, fugitive 

sources and during start up/shutdown 

and malfunction events and traditional 

emissions estimation techniques for 

less-reactive VOCs are the same as those 

for HRVOC. Thus, it is reasonable to 

suspect that these chemicals are also 

under-represented in the inventory. If 

these chemicals are under-represented 

in the inventory, the degree of 

underestimation may be less than for 

HRVOCs. One reason is that the 

processes that emit HRVOCs, such as 

ethylene plants, are often under very 

high pressures and this may increase the 

degree of underestimation more than 

would occur for emissions in lower 

pressure processes as one would expect 

leaks under higher pressures would 

tend to release a greater mass of 

emissions than lower pressure leaks. 

Also, many less-reactive VOCs are much 

lower in volatility than the HRVOCs 

which could also serve to reduce the 

amount of emissions underestimation. 

There is some evidence from ambient 

measurements that the less-reactive 

chemicals are underestimated in the 

emission inventory, but there are not yet 

the number of peer reviewed studies 

regarding these other VOCs that exist for 

HRVOCs making determination of 

appropriate adjustment factors 

problematic. Therefore, Texas chose not 

to adjust the reported inventory for the 

less-reactiveVOCs for the attainment 

demonstration modeling because of the 

lack of information regarding the 

appropriate level of emissions. TCEQ 

did conduct a study of ambient data, 

referred to in the SIP revision, 

indicating that emissions might be 

underestimated by a factor of 4.8. Based 

on this study, Texas performed a 

sensitivity run with the model to 

evaluate the impact potential errors in 

less-reactive VOC emissions might have 

on projected attainment. This sensitivity 

analysis indicated that the addition of 

less-reactive VOCs using a factor of 4.8 

could have an impact of 2–29 ppb on 

the peak ozone depending on the day. 

The performance of the model, however, 

was slightly worsened by the addition of 

the less-reactive VOCs indicating that 

possibly too much reactivity had been 

added. Other analyses performed by the 

University of North Carolina (Role of 

Modeling Assumptions in Mid-Course 

Review, HARC 12.2004.8HRB, 2005) 

adjusting only fugitive emissions of lessreactive VOCs by lower factors 

indicated no more than a 0.5 ppb 

increase in ozone levels. The main 

differences between the analyses were 

the assumptions regarding the amount 

of additional less-reactive VOCs and the 

amount of HRVOCs in the model. 

EPA is proposing to accept the 

attainment demonstration based on 

TCEQ’s approach to less reactive VOCs, 

because of the uncertainty on what 

adjustments might be appropriate and 

what impact those adjustments might 

have on the model. We understand that 

TCEQ is continuing to evaluate ambient 

data to determine what adjustments to 

the inventory might be appropriate. 

Texas has also undertaken a stakeholder 

process to identify additional ways to 

improve the emissions inventory. This 

stakeholder process will be vital to the 

improvement of future SIP revisions. 

EPA expects that future SIPs revisions 

will be based on improved emissions 

inventories of both less-reactive VOCs 

and HRVOCs. We note that the move to 

require the correlation equations for the 

estimation of less-reactive VOC will 

serve to improve the estimate of fugitive 

emissions. Improvements to the 

emission estimates for cooling towers 

and flares in less reactive VOC service 

should also be considered. Roles should 

also be found for emerging remote 

sensing technologies that have been 

shown to detect leaks from sources 

which have not been traditionally 

considered such as barge hatches and 

fittings on floating roof storage tanks. 

10. What Additional Evidence Did 

Texas Provide? 

The EPA’s 1996 guidance entitled 

‘‘Guidance on Use of Modeled Results to 

Demonstrate Attainment of the Ozone 

NAAQS’’ allows for the use of 

alternative analyses, called weight-ofevidence (WOE), to provide additional 

evidence that the proposed control 

strategy, although not modeling 

attainment, is nonetheless expected to 

achieve attainment by the attainment 

date. More specifically, the intent of this 

guidance was to be cognizant of the 

ozone NAAQS, which allows for the 

occurrence of some exceedances and to 

consider potential uncertainty in the 

modeling system. Thus, even though the 

specific control strategy modeling may 

predict some areas to be above the 

NAAQS, this does not necessarily mean 

that with the implementation of the 

control strategy, monitored attainment 

will not be achieved. As with other 

predictive tools, there are inherent 

uncertainties associated with modeling 

and its results. For example, there are 

uncertainties in the meteorological and 

emissions inputs and in the 

methodology used to assess the severity 

of an exceedance at individual sites. 

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. 

Since the future control case 

modeling in the Texas SIP revision 

predicts some areas still exceeding the 

ozone NAAQS, the TCEQ elected to 

supplement the control strategy 

modeling with WOE analyses. Texas 

submitted the following analysis as 

WOE: August 31st rare meteorology; 

additional reductions that were not 

modeled; comprehensive ozone metrics 

and ambient trends; alternative design 

value and addressing short-term 

excursions; and unusual wildfire 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58125 

activity. Each of these is discussed 

below. 

August 31st Rare Meteorology 

A combination of unusual 

meteorological conditions, extremely 

high temperatures and winds from the 

west, occurred on August 31, 2005. The 

record high temperatures recorded 

during the August 30–September 5, 

2000 period, with several days of 

maximum temperature ≥104°F (40°C), 

have occurred in this geographic area 

only once before in the previous 57 

years. On August 31st, the Houston 

Intercontinental Airport observed its 

highest temperature ever recorded in the 

month of August. High temperatures 

throughout the region led to higher than 

normal estimated biogenic emissions as 

the calculation of biogenic emissions is 

a strong function of temperature. Texas 

calculated that biogenic emissions 

within the HGB area were 

approximately 400 tons/day higher on 

August 31st than on August 25th which 

had more moderate temperatures. The 

elevated biogenic emissions in rural 

areas west of Houston were also high 

and, because of somewhat atypical 

winds from the west, available for 

transport into HGB. Texas used the 

source apportionment tool (OSAT) to 

analyze the contributing emissions to 

high ozone. The OSAT tool indicated 

that on the 31st, 78 ppb of the peak 

ozone could be attributed to biogenics 

as compared to 24 ppb that could be 

attributed to biogenics on the 25th. 

Other days of the episode also had high 

temperatures but only when combined 

with the west winds did the unusual 

impact of biogenics result. Texas points 

out that winds from the west are not 

typical of the days that have high ozone 

in Houston which usually occur on days 

with a flow reversal due to the land sea 

breeze effect. 

EPA agrees that the meteorological 

conditions on August 31st, which 

combined record high temperatures and 

winds from the west, were not typical 

of the conditions that lead to high ozone 

in the HGB area. The higher than 

normal biogenic emissions and winds 

from the west appear to have caused the 

31st to be a day that did not respond 

well to the adopted control strategy 

which is weighted toward control of 

point sources that are predominant in 

eastern Harris County. This strategy has 

been effective in reducing ozone levels 

on other days of the episode. On the 

31st, it appears much of the elevated 

ozone resulted from the increased 

biogenic emissions mixing with the 

NOX emissions present in the western 

portion of the HGB area. In this portion 

of the area, NOX emissions are primarily 

from on- and off-road mobile sources. 

To control ozone levels on days with 

routine conditions similar to August 

31st would require substantial 

additional controls on mobile and area 

sources beyond the levels in the current 

strategy. But because the conditions on 

the 31st are atypical, we believe the 

HGB area can attain and a shift in 

strategy is not warranted. 

EPA’s rules at 40 CFR 50, Appendix 

I permit the Regional Administrator to 

exclude values caused by stratospheric 

ozone intrusion or natural events in 

determining whether a NAAQS has 

been exceeded or violated. Additionally, 

EPA’s long-standing policy and 

guidance on the handling of air quality 

data affected by exceptional or natural 

events permits special consideration to 

be given to recorded air quality 

measurements that are affected by 

unusual events under certain 

circumstances. See, e.g., ‘‘Guidance on 

the Identification and Use of Air Quality 

Data Affected by Exceptional Events 

(July 1986)’’. However, this guidance 

and other guidance distinguish between 

those types of events which directly 

produce emissions of a pollutant or its 

precursors and meteorological 

conditions that may affect 

concentrations of a pollutant emitted by 

sources. In particular, EPA guidance 

provides that no consideration is given 

in determining whether the NAAQS are 

exceeded or violated for such things as 

inversions, stagnation of air masses, 

high temperatures or lack of rainfall. 

This language has recently been 

codified in an amendment to section 

319 of the Clean Air Act by P.L. 109–

59 [SAFETEA]. However, a reasonable 

distinction may be drawn between the 

determination of whether NAAQS are 

exceeded or violated during times when 

such meteorological conditions exist 

and the meteorological and emissions 

data sets used in prospective 

demonstrations of attainment. In the 

latter, our policy has been for States to 

examine the typical conditions that lead 

to high ozone when modeling to 

determine whether their control 

strategies are sufficient to provide for 

attainment and maintenance of NAAQS. 

(U.S. EPA, (1996), ‘‘Guidance on Use of 

Modeled Results to Demonstrate 

Attainment of the Ozone NAAQS’’, 

EPA–454/B–95–007.) In this case, the 

combination of conditions on the 31st 

are not typical and, in fact are quite rare. 

Therefore, EPA does not believe a shift 

in control strategy is warranted to 

address the unusual conditions on 

August 31st that are expected to occur 

so infrequently as to be unlikely to 

impact the area’s ability to attain the 

NAAQS. 

Additional Reductions Not Modeled 

The TCEQ believes potential 

additional emissions reductions will 

take place as a result of programs which 

have been and will be implemented in 

the HGB area but which are not 

reflected in the modeling. These 

reductions are not included in the 

modeling because, at present, these 

reductions are not quantifiable. 

Emission reductions that were not 

included in the model should improve 

the probability of HGB achieving 

attainment of the ozone NAAQS. First, 

as industries improve their monitoring 

capabilities and reduce their HRVOC 

emissions, the TCEQ anticipates 

collateral reductions of other VOCs that 

are present in HRVOC streams. For 

instance, the TCEQ developed 

regulations requiring owner/operator of 

flares in HRVOC service to install flowmeters and comply with maximum tip 

velocity and minimum heat content 

requirements to ensure proper 

combustion by the flare. The tip velocity 

and heat content requirements apply at 

all times, not only when the flare is 

combusting HRVOC streams. Because 

many of these flares are also used for 

non-HRVOC streams, the regulations 

will often result in a reduction of lessreactive VOCs as well. Similarly, TCEQ 

has improved the leak detection and 

repair program for streams with more 

than 5% HRVOC content. When leaks 

from streams containing both HRVOCs 

and less reactive VOCs are repaired, 

other less-reactive VOCs will also be 

reduced. EPA agrees that these collateral 

reductions are likely to occur, but we 

believe the potential benefit of these 

unmodeled emission reductions has 

been partially lost because TCEQ allows 

emission reductions of less-reactive 

VOCs to offset small increases in 

HRVOCs using the Maximum 

Incremental Reactivity (MIR) scale (see 

Section II.B.4.). It is likely that some of 

the benefit will be realized because we 

do not expect that many companies will 

implement the additional monitoring of 

less reactive VOCs that would be 

necessary to establish baselines 

necessary to participate in the trading 

program. Also, under the TCEQ rules, 

less reactive fugitive emissions 

reductions cannot be credited toward 

HRVOC increases so collateral 

reductions in fugitive emissions should 

be fully realized. Another issue is the 

uncertainty in the less-reactive VOC 

inventory. As discussed in the section 

on emissions inventory uncertainty, it 

may be that less-reactive VOCs are 

under-represented in the base case 

58126 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

inventory. Because of uncertainty about 

the inventory, these collateral 

reductions may not serve to reduce VOC 

emissions below what was assumed in 

the model. These collateral reductions 

will serve to reduce the degree of any 

potential under-representation in the 

inventory and thus reduce this area of 

uncertainty in the attainment 

demonstration. 

A second program that should result 

in additional reductions is the 

Environmental Monitoring Response 

System (EMRS). The TCEQ and the 

HRVOC regulated community have 

expanded the real-time ambient 

monitoring network of specific VOCs in 

the HGB area. A primary goal of EMRS 

is to prevent HRVOC emissions from 

creating situations that may lead to high 

levels of ozone. The near real time 

monitoring and response built into the 

program, which is further described in 

the TSD, will provide rapid feed back 

that should help identify and quickly 

correct the releases that can lead to high 

levels of ozones. EPA believes this 

added scrutiny of ambient VOC levels 

will result in improved overall program 

effectiveness, and could identify 

previously unknown sources of 

emissions that could be controlled to 

further reduce emissions. 

The TCEQ believes that additional 

reductions will also be achieved 

through its public web-based access to 

an emission event database 

incorporating lower reportable 

quantities of VOCs beyond just the 

HRVOCs of most concern. This database 

puts facility performance regarding 

unauthorized emission releases at the 

public’s fingertips. As public awareness 

of the number and amount of these 

releases increases, industry is expected 

to respond in a manner similar to its 

response to the Toxics Release 

Inventory program which has resulted 

in large reductions in Toxic emissions. 

EPA agrees awareness and 

documentation of these events should 

prompt industry to begin to evaluate the 

causes of these events and institute an 

enhanced program to ensure that the 

potential of an event is significantly 

minimized. 

Texas believes the projected 

emissions for electric generating units 

outside the nonattainment area are 

probably too high. The current HGB SIP 

attainment demonstration modeling 

only excludes from the future case 

emissions projections for units that have 

formally indicated an intent to cease 

operation or that will be retired/reduced 

under agreed orders. The future 

projected case modeling inventory may 

include sources that will in fact be 

retired in (and/or prior to) 2007 as 

newer, more cost effective plants come 

online as Texas utilities continue the 

transition to a fully deregulated market. 

If this occurs, additional reductions 

could result which are not accounted for 

in the current SIP because the newer 

facilities would have lower emission 

rates. EPA agrees that deregulation will 

encourage the retirement of less efficient 

plants. Some of the benefit of this 

process may already be incorporated in 

the projections because Texas has 

projected newly permitted units will 

operate at 75% capacity in its projection 

of future emissions for electric utility 

emissions. It may be that newly 

permitted plants operate closer to full 

capacity as less efficient plants are 

curtailed or retired such that overall 

projected emission levels do not 

decrease as much. Some reductions 

should still occur because the newer 

plants will be cleaner than the older 

plants. A factor that weighs toward the 

projections of future emissions outside 

the nonattainment being too low is the 

findings of a report on emissions from 

offshore facilities too recent to be 

included in the SIP which indicates that 

projected emissions from these facilities 

may be significantly higher than what 

was modeled. Considering these factors 

together, EPA believes that NOX

emissions outside the nonattainment 

area are slightly if at all less than 

projected and provide little additional 

evidence the area will attain. 

Texas also believes that NOX emission 

projections inside the nonattainment 

area are overestimated. Inside the eight 

county nonattainment area, the Mass 

Emissions Cap and Trade (MECT) 

program for NOX applies. For sources 

with permits in hand when the first cap 

allocations were established but which 

had not yet operated, TCEQ issued 

allowances based on the allowable 

emissions in the permit (so called 

‘‘allowable allowances’’). Allowable 

allowances are those allocated to 

sources based on permits issued prior to 

the initiation of the MECT program, but 

not in operation for sufficient time to 

establish a baseline. During the interim 

period, until a baseline is established, 

sources operate complying with the 

‘‘allowable allowances.’’ Then, based on 

the actual emissions during the baseline 

period, the State grants ‘‘actual 

allowances.’’ Because typically these 

facilities are not operating at their full 

allowable rates, but significantly below 

those values, a source will get fewer 

‘‘actual allowances’’ than the ‘‘allowable 

allowances’’ it was granted based on the 

permit. Therefore, as these newly 

permitted facilities establish baselines 

from which to grant ‘‘actual’’

allowances, the NOX cap in the HGB 

will decrease overall. The TCEQ 

examined the 2002 and 2003 permit 

database and found that only 33 to 39 

percent of the allowable allowances for 

permitted facilities were used. The 

modeling was based on the ‘‘allowable 

allowances’’ because it was not possible 

to predict how much lower the actual 

allowances will be than allowable 

allowances. The number of allowable 

allowances is not insignificant. The 

TCEQ registry currently carries 18,658 

allowable allowances for 2007 which 

could translate into a potential 

additional NOX emissions reduction 

beyond what was modeled of up to 31 

tpd if current trends for the conversion 

of allowable allowances to actual 

allowances continue. EPA agrees that as 

allowable allowances are converted to 

actual allowances, actual emissions will 

be less than the emissions that were 

modeled which should result in greater 

improvement in air quality than 

projected in the model. 

In summary, EPA believes that TCEQ 

has provided sufficient evidence that 

NOX emission levels will be lower than 

those projected in the model and thus, 

air quality improvements should be 

better than predicted by the model. We 

also believe the reductions that will 

occur due to collateral VOC reductions 

and brought about by the EMRS system 

and emission events data base will 

reduce the uncertainty in the model due 

to uncertainty in the VOC inventory. 

Comprehensive Ozone Metrics And 

Ambient Trends 

Based on the ambient data, the 1-hour 

ozone design values for the HGB area 

have decreased significantly from 260 

ppb in 1982 to 175 ppb in 2003. Texas 

used this initial data to estimate a trend 

that demonstrated that attainment of the 

1-hour standard would be reached 

sometime after 2020. The area’s design 

value dropped significantly during the 

1980s, then flattened out during the 

1990s, hovering around 200 ppb. Design 

values recently have resumed their 

downward trend and are at the lowest 

values seen in at least the last twenty 

years. EPA notes that the 2004 design 

value has further decreased to 169 ppb. 

The current trend may be partly due to 

meteorological conditions in recent 

years, but it is almost certainly 

accelerated by emission reductions 

made since the 2000 SIP revision. If the 

design value continues to drop at a rate 

comparable to that seen in the most 

recent five-year period, then attainment 

would occur sometime around 2010. 

But the amount of emissions reductions 

is expected to increase each year until 

2007 as a result of rules adopted in the 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58127 

2000 SIP revision and in this SIP 

revision. Consequently, the design 

values are expected to decrease more 

rapidly as 2007 approaches. This 

simplistic analysis alone by no means 

proves the area will attain the standard 

by 2007, but EPA agrees the recent 

design value trends are consistent with 

reaching attainment by 2007. 

Alternative Design Value And 

Addressing Short-Term Excursions 

As discussed previously, the 

attainment strategy is based on a two 

pronged approach, control of routine 

emissions and a short-term limit to 

control emission events. The TCEQ 

believes the traditional modeling does 

not replicate ozone produced by the 

sudden sharp increases in HRVOC 

emissions that can occur in the HGB 

area due to non-routine emission 

releases. TCEQ argues that this technical 

deficiency provides an explanation for 

why the model’s peak simulated ozone 

concentrations were all below the HGB 

area’s design value in 2000. The actual 

design value calculated for the years 

1999–2001 was 182 ppb, while base 

case simulated peak ozone 

concentrations were below 160 ppb on 

every day but August 31st. The TCEQ 

believes that the influence from shortterm releases should be removed from 

the area’s design value to determine the 

design value based on routine 

emissions. This alternative design value 

theoretically will more closely 

correspond to the routine urban ozone 

formation captured by the model. To 

remove the influence of short-term 

releases, TCEQ applied Blanchard’s 

technique (Statistical Characterization 

of Transient High Ozone Events Interim 

Report; December 21, 2001) to the 1999–

2001 AIRS data. This technique uses a 

threshold of a 40 ppb rise in ozone 

concentration in 1 hour to distinguish 

between sudden rises in ozone from the 

more typical case where ozone increases 

more gradually. Removing all days with 

identified sudden ozone concentration 

increases (SOCI), an alternate design 

value of 144 ppb was calculated by 

TCEQ. The base case includes seven 

days with modeled peak ozone greater 

than 144 ppb, so the modeled peaks, in 

fact, correspond well with the (nonSOCI) design value and in fact the 

model may be over-predicting the ozone 

resulting from routine emissions. If the 

model is over-predicting the ozone due 

to routine emissions in the base case, 

then it is likely the model is overpredicting the ozone due to routine 

emissions in the future case projections 

providing additional evidence that the 

control strategy will sufficiently reduce 

the ozone from routine emissions. 

EPA considers the alternative design 

value approach one tool in evaluating 

the possible impact of non-routine 

emission releases, particularly releases 

of HRVOCs on the design value. By 

removing the days that have rapid ozone 

formation and therefore are possibly the 

result of large releases, it is possible to 

get a sense of the potential impact of 

large emission releases on the design 

value. We are not convinced, as yet, that 

all occasions where ozone rises by 40 

ppb from one hour to the next are 

caused by releases. Some of these events 

could be caused by continuous plumes 

of ozone sweeping across a monitor as 

winds shift direction. Wind shifts are a 

common occurrence in the HGB area 

and are likely responsible for some of 

these SOCI events. The TCEQ analysis 

also did not screen out widespread 

exceedences unlikely to be the result of 

a non-routine event. Still, we agree that 

emission events do impact the design 

value to a degree that is difficult to 

quantify. Therefore, we agree that 

considering the alternative non-SOCI 

design value provides additional 

evidence that the future design value 

will reach the standard in the future 

case as Texas has developed a strategy 

to control both routine and event 

emissions, thus reducing both 

contributions to the design value. 

Wildfire Activity: In 2000, there was 

an unusually large amount of wildfire 

activity in Southeast Texas due to 

drought conditions and extreme 

temperatures in the August-September 

time frame. This is documented in 

Section 3.7.2 of the SIP that shows that 

more than 5 times as many acres burned 

in 2000 as in any of the other years 

between 1999 and 2003. It is not 

expected the number and scope of fires 

modeled in the current SIP attainment 

demonstration modeling would be 

reasonably expected in future years. A 

sensitivity analysis was conducted to 

quantify the impact of wildfires on the 

future year ozone level in the HGB 

indicating wildfire activity does have an 

impact on the HGB future ozone levels 

(i.e., 0.1 ppb to 1.7. ppb). EPA agrees 

that the amount of wildfire activity was 

unusual in 2000 and should not 

generally be expected in most years. 

Therefore, we agree that this is 

additional evidence that indicates 

improved probability that the area will 

attain in future years because the 

projected modeled emissions are higher 

due to wildfires than should generally 

be encountered in future years. 

11. Is the One-Hour Attainment 

Demonstration Approvable? 

EPA believes that the combination of 

photochemical modeling and other 

evidence (WOE) indicates that the 

revised control strategy will bring the 

area into attainment. This 

demonstration is based on new 

information not available at the time the 

currently approved SIP was developed 

and represents a significant 

improvement over past efforts to model 

Houston. Specific improvements 

include: 

• Improved representation of 

Houston’s complex meteorology. 

• Recognition of the importance of 

HRVOCs. 

• Recognition that HRVOCs are 

underestimated in the emissions 

inventory. 

• Recognition of the potential impact 

of emissions variability on ozone levels. 

EPA believes that the modeling 

projects significant improvement due to 

reductions in routine emissions. EPA 

believes TCEQ has shown through the 

modeling of routine emissions that the 

portion of the ozone due to routine 

emissions will be sufficiently reduced. 

The modeling of routine emissions does 

not predict attainment on all days. The 

circumstances that led to the very high 

exceedance on August 31, have been 

shown to be unusual and thus EPA 

concludes the 31st should not be used 

to drive the control strategy. On other 

days of the episode, ozone levels have 

been shown to be reduced to below or 

just slightly above the standard. The 

wildfires that occurred during the 

episode also are a rare event occurring 

because of the high temperatures and 

drought conditions. Removing the 

influence of wildfires from the modeling 

brings all of the days with the exception 

of August 31 within 3.8 ppb of the 

standard. Texas has provided evidence 

that additional emission reductions will 

occur of both VOC and NOX. EPA 

particularly believes the expected 

additional NOX reductions will provide 

additional ozone benefit that could 

offset the small amount the modeling of 

routine emissions shows the area to be 

above the standard. The additional 

reductions in VOC expected from 

collateral reductions due to the HRVOC 

rules and due to the implementation of 

the EMRS system and the event 

reporting data base should at least 

partially mitigate any errors in the nonHRVOC inventory used for the 

attainment modeling. 

The model’s under-prediction of high 

ozone levels using routine emissions 

have been examined by TCEQ. TCEQ 

has proposed that two phenomena 

(routine and non-routine emissions) 

drive the HGB design value and that it 

is appropriate to estimate an alternative 

design value that does not include the 

effects of non-routine emissions. If 

58128 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

TCEQ’s estimated alternative design 

value (144 ppb) is an accurate 

representation of the design value due 

to routine emissions, then the control 

strategy modeling should reduce ozone 

levels due to routine emissions below 

the ozone standard. TCEQ addresses the 

non-routine emissions with the shortterm limit that is expected to reduce the 

contribution to the HGB area’s ozone 

level due to non-routine emissions such 

that non-routine emissions should not 

occur frequently enough at sensitive 

locations and times to impact the area’s 

attainment of the 1-hour standard. As 

discussed in the TSD, the alternative 

design value probably overestimates, to 

some degree, the impact of short-term 

releases but still provides evidence that 

the current strategy to reduce routine 

emissions should be successful in 

addressing that portion of the 1-hour 

problem due to routine emissions and 

supports TCEQ’s two pronged approach 

to achieving attainment of the 1-hour 

standard. 

Finally, EPA believes the evaluation 

of ambient data trends indicates that the 

area is on a track that is consistent with 

achieving attainment of the one-hour 

standard by 2007. 

B. New Control Measures 

1. What Are the New Control Measures 

in These SIP revisions? 

TCEQ has adopted the following new 

control measures since the previously 

approved SIP revision: 

• Annual Cap on HRVOC emissions 

• Hourly (short-term) limit on 

HRVOC emissions 

• Improved requirements for HRVOC 

fugitive emissions 

• Requirements for Portable Gasoline 

containers 

2. What Are the Annual Cap and Shortterm Limit on HRVOC emissions? 

As discussed in Section II.A.1, Texas 

relied primarily on two sets of modeling 

in developing its control strategy. One 

set of modeling, performed by TCEQ, is 

largely a traditional model formulation 

that examines the routinely variable 

emissions which occur in the HGB area. 

Through this modeling, TCEQ 

established that NOX emissions would 

not have to be reduced as much as 

previously planned and routine 

emissions of highly-reactive VOC 

emissions would have to be reduced. 

Through the second set of modeling, 

examining the impact of large nonroutine releases of HRVOCs, it was 

established that the frequency and 

magnitude of large non-routine releases 

of HRVOCs should also be reduced. 

To reduce the routine emissions of 

highly-reactive VOCs, Texas adopted an 

HRVOC emissions cap-and-trade 

(HECT) program. This program 

establishes an annual cap on emissions 

of ethylene, propylene, butadiene and 

butenes from cooling tower heat 

exchange systems, flares, and vent gas 

streams in Harris County. The rules 

establishing the cap-and-trade system 

are contained in 30 TAC Chapter 101, 

Subchapter H, Division 6. The rules 

establishing the monitoring and record 

keeping necessary to determine 

compliance with the HECT are 

contained in 30 TAC , Chapter 115, 

Subchapter H. EPA has reviewed the 

monitoring rules and proposed approval 

of the Chapter 115 rules. (See E-Docket 

R6–OAR–2005–TX–0014 ) EPA is 

reviewing the HECT program rules with 

respect to EPA’s Economic Incentive 

Program guidance and a separate 

proposed rule is being developed. (See 

E-Docket R06–OAR–2005–TX–016) 

Because the emission reductions 

achieved by the HECT program are 

relied on in the attainment 

demonstration, EPA cannot finalize an 

approval of the attainment 

demonstration unless or until the HECT 

program and the Chapter 115 rules have 

been approved. In this document, we 

discuss how the controls on HRVOCs 

have been modeled and support the 

attainment demonstration. 

In projecting the HRVOC emissions 

that would occur after the HECT annual 

cap was implemented, TCEQ included a 

5 percent safety factor in the attainment 

demonstration modeling. In other 

words, rather than model the levels 

established by the cap, Texas included 

5 percent additional emissions of 

HRVOCs in the model. This safety factor 

was necessary because of the 

uncertainty that is introduced into the 

modeling by using an annual cap to 

achieve a short-term standard such as 

the National Ambient Air Quality 

Standard for ozone. On any given day 

more sources could be operating above 

their annual average emissions than 

below their annual average emissions. 

The 5 percent safety margin provides 

some room to account for this day-today variation in routine emissions. 

As discussed previously, a large 

number of scenarios were simulated in 

the Project H13 work, examining the 

impact of releases of various sizes, times 

and locations. This study demonstrated 

that releases at the worst-case place and 

time of 1000 lb/hour could have a 1–

2ppb impact on peak ambient ozone 

levels. To minimize frequency of these 

events, TCEQ established an hourly 

limit on emissions from process vents, 

flares, cooling towers and pressure relief 

devices. The hourly limit on emissions 

is 1200 lbs/hour and is established at 

§§ 115.722 and 115.761. 

3. How Are the Annual Cap and the 

Short-Term Limit Related? 

Texas has included features in the 

rules defining the interaction between 

the annual cap and short-term limit that 

are unique to the HECT. Typically, all 

emissions during the year would be 

counted toward compliance with an 

annual cap. In establishing a cap-andtrade system for the petrochemical 

industry in the HGB area, TCEQ felt it 

necessary to consider the possibility of 

major upsets. TCEQ believed that nonroutine emissions from process upsets, 

while likely to occur, are not predictable 

and therefore could make management 

of emissions under an annual cap 

difficult. Therefore, TCEQ established in 

its rule that emissions above the 1200 

lb/hr short-term limit are not counted 

toward compliance with the annual cap 

but rather expected to be controlled by 

the short term limit. TCEQ was 

particularly concerned about the 

potential situation where a single large 

release could force a smaller source to 

shut down for the remainder of the year 

because its allowances had been 

exhausted. 

Although EPA agrees that a forced 

shutdown of smaller sources is possible, 

it believes that many upsets can be 

avoided by a source through the 

development and implementation of 

operation and maintenance plans that 

address start-up, shutdown and 

malfunction of process equipment and 

application of good air pollution control 

practices such as required by 40 CFR 

60.18(d). EPA notes that application of 

the aforementioned procedures would 

significantly reduce the emissions 

associated with such start-up, shutdown 

and malfunction events and could avoid 

a the need for a forced shutdown. In 

addition, planning and management of 

emissions by the source including 

participation in the credit market 

should also avoid a forced shutdown 

while ensuring compliance with the 

annual cap. 

Emissions above the short-term limit 

would still be subject to enforcement as 

a violation of the short-term limit, but 

only 1200 lbs would be reported for 

compliance with the annual cap during 

those hours where emissions exceed 

1200 lbs. It is our expectation that the 

root cause of the conditions giving rise 

to the emissions above the short-term 

cap will be identified and corrected. 

Moreover, the source is still required to 

use good air pollution control practices 

consistent with the applicable NSPS (40 

CFR 60.11(d)) and MACT standards or 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58129 

other applicable Federal or State 

programs. 

The structure of the Texas HECT 

program, which does not require 

emissions above the short-term limit to 

be counted against the long-term cap, is 

a significant departure from past 

practices for cap-and-trade programs 

such as the Title IV Acid Rain program 

and the Houston NOX cap-and-trade 

programs. EPA’s Economic Incentive 

Program guidance regarding mass 

emissions cap-and-trade programs 

indicates that all sources in the program 

should account for all of their 

emissions. See section 7.4 of the EIP 

Guidance. We believe, in this instance, 

the approach of not counting emissions 

above the short-term limit toward the 

annual cap has both advantages and 

disadvantages as discussed below. We 

are inviting comment on approving a 

program with this structure, as we 

remain concerned about excess 

emissions resulting from poor operation 

and/or poor maintenance. 

We believe the structure of the TCEQ 

HECT rule has the advantage that it 

establishes a clear procedure for how 

emissions during non-routine events 

will be handled. For every hour during 

a large emissions event, the source will 

include 1200 lbs toward meeting its 

annual cap. This will avoid disputes 

about the validity of data during large 

emission events, when monitoring may 

be less reliable. The rule clearly defines 

the procedures to be followed during an 

emission event. Sources will have no 

choice but to ensure that at the end of 

the compliance period they have 

sufficient allowances to cover all of the 

emissions up to the 1200 lb limit, or else 

face deductions from their compliance 

account and other potential penalties. In 

addition, emissions above that level 

would be subject to enforcement under 

the short term limit. 

On the other hand, the structure of the 

rule has the disadvantage that some of 

the incentive to prevent large releases is 

lost by excluding emissions above the 

short-term limit from the annual cap. In 

addition, some of the incentive for 

reducing the size of large events, when 

they occur, may also be lost. With the 

annual cap-and-trade program’s 

exclusion of emissions above the hourly 

(short-term) limit, it is probable that 

fewer violations of the annual cap will 

occur than if the exclusion had not been 

provided. For sources that would have 

violated the annual cap if emissions 

above the short-term limit were 

considered, it may be harder to promote 

systemic changes at those sources to 

reduce overall emissions. 

Having looked at the advantages and 

disadvantages, we are proposing 

approval of the program. We are 

proposing approval because, even 

though it provides an exclusion for nonroutine emissions above short-term limit 

from the annual cap, it provides new 

enforceable limits that are an 

improvement on the status quo, and we 

believe the annual cap in conjunction 

with the short term limit will achieve 

the goals of the attainment 

demonstration as indicated by the 

modeling analysis. The annual cap 

should result in the necessary 

reductions in routine emissions and the 

short-term cap should result in the 

necessary reduction in the amount and 

frequency of non-routine emission 

events. We note that the program rules 

require TCEQ to audit the HECT 

program every three years, and facilities 

have to provide compliance reports 

annually, so it will be readily apparent 

if the goals of the rules are being 

achieved. 

We believe the program will achieve 

the necessary reductions in routine 

emissions because the size of the shortterm limit is such that only truly nonroutine emissions will not be counted 

toward the annual cap. Based on 

evaluation of the emission rates that 

were modeled in the January 2003 SIP, 

the 1200 lb/hour limit is expected to be 

about ten times larger than the average 

hourly emission rate at the largest 

sources of HRVOCs. This order of 

magnitude difference between the shortterm limit and the average annual 

hourly emissions ensures that sources 

will not routinely operate near or above 

the short-term limit, thus achieving the 

goal of reducing routine emissions. 

Also, while the structure of the 

HRVOC rules anticipates that emission 

events will not be completely 

eliminated, EPA believes that it 

provides sufficient disincentives that 

sources will reduce the frequency and 

magnitude of large emissions events 

such that emission events would not be 

expected to frequently impact peak 

ozone levels. The Project H13 report 

estimated from historic information that 

it is probable that at least one event will 

occur annually at a time and location to 

impact peak ozone. This indicates that 

while emission events are frequent in 

the Houston area, emission releases at 

the place and time that impact peak 

ozone do not occur nearly as frequently. 

As noted elsewhere, it is possible that 

events are more frequent than found in 

the project H13 report as past 

monitoring practices may not have 

detected all releases. 

It is necessary to reduce the frequency 

of emission events so that emission 

events do not interfere with attainment 

of the 1-hour NAAQS, which only 

allows an average of one exceedence per 

year. Based on the study, we believe the 

hourly emission limit will achieve this 

goal. After the institution of the short 

term limit, EPA expects that emissions 

events impacting peak ozone levels will 

be reduced in frequency to fewer than 

one per year. The frequency of emission 

events will be reduced as facilities take 

actions to prevent violations of the short 

term limit such as adding additional 

flare gas recovery capacity so more 

releases can be captured and routed 

back to the process. Sources that fail to 

take appropriate actions and which 

violate the short term limit will be 

subject to enforcement. While events 

may occur that impact ozone levels at 

other locations than where the peak 

ozone level occurs, these events, 

because they are occurring in areas with 

lower ozone levels, would not be 

expected to impact attainment of the 1- 

hour NAAQS. 

Again, EPA recognizes that the 

approach of providing this partial 

exclusion for emissions above the shortterm cap is a departure from practices 

in other cap and trade programs such as 

the acid rain program and our guidance. 

We currently believe this approach is 

only warranted in consideration of the 

Houston area’s unique situation that 

combines an extensive petrochemical 

complex and the availability of the 

extensive data and analysis that were 

generated by the intensive ozone study, 

TxAQS 2000 and in conjunction with a 

short-term limit. Consideration of this 

novel approach is warranted in order to 

balance the need to reduce both routine 

and upset emissions of HRVOC, but also 

recognizes that large upset emissions 

may never be completely eliminated in 

the petrochemical industry. Because of 

the uniqueness of this approach, 

however, we invite comment on our 

proposed approval of this facet of the 

Texas plan. 

4. Can Reductions in Less-reactive VOCs 

Be Made Instead of Reductions in 

HRVOCs? 

One feature of the Texas rules for 

capping HRVOCs is that sources can 

make reductions in other less-reactive 

VOCs to generate allowances for the 

HRVOC cap. The VOC reductions are 

used to generate emission reduction 

credits (ERCs), in accordance with the 

Emission Credit Banking and Trading 

Program, referred to as the ERC rule, 

established at 30 TAC Chapter 101, 

Subchapter H, Division 1. These ERCs 

can then be converted to allowances 

under the HECT program. The amount 

of allowances is determined based on 

the ratio of the reactivity for the 

speciated VOCs being reduced to the 

58130 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

reactivity of an HRVOC. Reactivity 

values are obtained from the Maximum 

Incremental Reactivity Scale (MIR), 

California Code of Regulations, Title 17, 

Chapter 1, Section 94700, concerning 

MIR values for Compounds. The amount 

of allowances that can be generated is 

limited to 5% of a facility’s cap. To 

generate less-reactive VOC emission 

reduction credits, sources must meet the 

same monitoring requirements for the 

less-reactive VOC streams that are 

required for HRVOCs streams. 

As mentioned earlier, EPA is 

evaluating the HECT rule in a separate 

Federal Register notice being developed 

concurrently. In addition, EPA is 

evaluating TCEQ’s ERC rule in a 

separate Federal Register also being 

developed concurrently. (See E-dockets 

R06–OAR–2005–TX–0016 and R06–

OAR–2005–TX–0006). Since this 

attainment demonstration depends on 

the reductions achieved by the HECT 

program, we cannot approve the 

attainment demonstration unless the 

HECT rules are first approved. Also, the 

conversion of ERCs to HECT allowances 

will not be approved until the 

underlying ERC rules are approved. 

Below we describe the impact of the 

conversion of allowances based on the 

MIR scale on the attainment 

demonstration. EPA has generally 

classed VOCs into two groups: reactive 

and non-reactive. All reactive VOCs 

have traditionally been treated equally 

for regulatory purposes. The findings of 

the TxAQS study, indicate that 

reactivity of certain chemicals and their 

prevalence in the HGB area are causing 

a disproportionate impact on ozone 

levels in the area. Thus, these HRVOCs 

were targeted for control. Texas is 

making an allowance for a small 

increase in HRVOCs (up to 5%) above 

the new emissions levels to be offset 

with larger reductions in less-reactive 

VOCs. Modeling sensitivity analyses 

were performed by the University of 

Texas and documented in a report, 

titled ‘‘Survey of Technological and 

Other Measures to Control HRVOC 

Event Emissions.’’ In this report, trades 

of less-reactive VOCs much larger than 

would be allowed with the 5% cap were 

considered. In the sensitivity runs, the 

impacts ranged from a 2.1 ppb increase 

to a 3 ppb decrease in the peak ozone, 

depending on the episode day and the 

assumptions made about the lessreactive chemical that was reduced. The 

researchers looked at the impact of 

adding between 15 and 33 tpd of 

HRVOC to the model while removing 

the requisite amount of less reactive 

VOCs. Under the rule, capping trades at 

a 5% increase in highly reactive VOCs, 

an increase of less than 2 tpd of 

HRVOCs would be all that could be 

allowed. Therefore, the impact of the 

actual program will be quite small. 

We believe that the generation of 

HRVOC allowances of up to 5% of a 

sources annual cap using reductions in 

less-reactive VOCs will not interfere 

with the area’s ability to attain the 

NAAQS. We are proposing approval 

because the impact on the attainment 

demonstration will be very small. In 

addition, for sources that participate in 

the program, it will have the advantage 

of implementing additional source 

monitoring on less-reactive VOCs. Our 

proposed approval does not represent a 

general endorsement of the use of the 

MIR scale for use in SIPs. In this 

instance, with the aforementioned 

technical support, we believe this is an 

acceptable approach which is consistent 

with EPA’s recently issued ‘‘Interim 

Guidance on the Control of Volatile 

Organic Compounds in Ozone State 

Implementation Plans’’ (August 25, 

2005). EPA will continue investigating 

how best to incorporate reactivity in the 

regulation of VOCs. 

5. What Estimates of Flare Efficiency 

Are Made in the SIP Revision? 

For purposes of estimating emissions 

for compliance with the Cap, the TCEQ 

rule requires companies to assume that 

properly operated flares achieve 99% 

destruction efficiency for C2 and C3 

hydrocarbons and 98% destruction 

efficiency for all other hydrocarbons. To 

insure these destruction efficiencies are 

achieved, the TCEQ rules require 

sources to monitor continuously to 

demonstrate compliance with the 

operating parameters of 40 CFR 60.18. 

Sources not operating in compliance 

with 60.18 are subject to enforcement. 

In addition, during periods when a flare 

operates outside the parameters of 

60.18, companies are to assume 93% 

destruction efficiency. EPA has 

proposed approval of these rules. (See 

E-Docket R6-OAR–2005-TX–0014 ) The 

assumptions regarding destruction 

efficiency impact the projected 

emissions in the model. TCEQ has 

provided the justification for these 

assumptions in Appendix L of the SIP. 

TCEQ relies on data from flare studies 

initiated by EPA in the early 1980’s that 

indicate that a properly operated flare 

should achieve destruction efficiencies 

of 98%. (Flare Efficiency Study, July 

1983, PB83–261644, Evaluation of 

Efficiency of Industrial Flares: Test 

Results, May, 1984, PB84–199371) 

These studies provided the basis for the 

development of 40 CFR 60.18. Texas 

used the data from these studies on 

ethylene and propylene to estimate that 

for these chemicals destruction 

efficiencies of 99% should be achieved 

by a properly operated flare. 

Emission estimates from flares will 

always be a source of uncertainty 

because emissions from flares cannot be 

directly measured with today’s 

technology. EPA is proposing to accept 

the estimates used for flare destruction 

efficiency for use in the attainment 

demonstration because the estimates are 

based on the best information available. 

We, however, remain concerned about 

the uncertainty created in the 

attainment demonstration by having a 

significant source of emissions which 

cannot be directly measured. 

We note that some operating 

parameters for flares such as steam and 

air assist ratios are not covered 

specifically by 40 CFR 60.18 but some 

studies have indicated these parameters 

can impact flare efficiency. Because of 

the prevalence of flares in the HGB area, 

we believe Texas should strongly 

consider, for both flares in HRVOC 

service and general VOC service, 

requirements for monitoring steam and 

air assist ratios to insure that operators 

maintain these parameters, not covered 

by 40 CFR 60.18, in a range to insure 

optimum combustion. We also 

encourage TCEQ to pursue new 

technology such as the Fourier 

Transform Infrared Spectrophotometer 

which would eventually allow the 

direct measurement of destruction 

efficiency in the field. 

6. How has the Texas Leak Detection 

and Repair Program Been Strengthened? 

For a number of years, TCEQ has 

implemented a leak detection and repair 

program as part of its program to control 

VOCs. When TCEQ determined that 

additional reductions of HRVOCs were 

needed, they established a number of 

new requirements for leak detection and 

repair of components in HRVOC service. 

The changes include, among other 

things, the following improvements: 

• Inclusion of connectors in the 

program. 

• Inclusion of other non-traditional 

potential leak sources such as heat 

exchanger heads and man-way covers. 

• Elimination of allowances for 

skipping leak detection periods for 

valves. 

• Requirements for third party audits 

to help insure that effective leak surveys 

and repairs are conducted. 

• Requirements that ‘‘extraordinary’’

efforts be used to repair valves before 

putting them on the delay of repair list. 

For a full discussion of the 

improvements to the program, see the 

Technical Support Document for this 

action. We have proposed approval of 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58131 

3The special inventory was developed by asking 

the largest facilities in the HGB area to provide 

daily emission estimates for the time period of the 

TxAQS 2000 study. 

these changes. (See E-Docket R6-OAR–

2005-TX–0014 ) 

7. How Have the Benefits of the Leak 

Detection and Repair Program Been 

Projected? 

The nature of fugitive emissions 

introduces a great deal of uncertainty in 

estimating fugitive emission rates. Much 

of this uncertainty is unavoidable given 

the impossibility of estimating 

emissions from each leaking 

component. In this SIP revision, TCEQ 

has increased the amount of modeled 

HRVOC emissions above reported levels 

based on ambient measurements as 

described previously. As part of this 

adjustment, fugitive emissions were also 

increased above reported levels. Below 

we explain why this increase in the 

modeled emissions to match ambient 

measures may have been necessary 

because of possible problems with 

assumptions regarding control 

efficiency and rule effectiveness for 

fugitive emissions that were made in the 

State’s emissions inventory. EPA also 

believes these past practices are being 

improved to reduce the uncertainty of 

future estimates. 

Control Efficiency: Past TCEQ 

emission inventory practices allowed 

companies the option of using average 

Synthetic Organic Chemical 

Manufacturing Industry emission factors 

in combination with estimated control 

efficiencies to estimate emissions. Since 

this approach does not employ the data 

on the number of leaking components or 

the concentrations of leaks, it 

potentially misjudges emissions. The 

control efficiencies TCEQ has allowed 

sources to assume are higher than EPA 

has projected for similar control 

programs. For example, in past 

estimates for a similar program to the 

Texas program, EPA had estimated a 

92% control efficiency, where Texas has 

allowed sources to assume a 97% 

control efficiency. See the TSD for a 

more complete discussion. The 

adjustment to the inventory based on 

ambient measurements could account 

for discrepancies in assumed control 

efficiencies. 

Rule Effectiveness: Rule effectiveness 

is a concept that tries to account for 

difference between reported emissions 

and actual emissions. Sources generally 

assume ideal program implementation 

in reporting emissions when actual 

program implementation may be less 

than ideal. In the case of fugitive 

emissions, a 100% rule effectiveness 

would assume that facilities are 

completely accurate in their component 

counts and detect and repair all of the 

leaking components. Clearly, in 

practice, 100% effectiveness is only a 

goal that can be strived for. Again, the 

adjustment to the emissions inventory 

based on ambient measurement is 

necessary, in part, due to rule 

effectiveness issues. 

It is EPA’s understanding that, prior 

to adjusting the inventory, TCEQ 

assumed a rule effectiveness of 100% 

for sources that participated in its 

special inventory.3 Because of the 

number of sources in the special 

inventory, it is believed that the rule 

effectiveness is nearly 100%. EPA’s 

National Enforcement Investigations 

Center has performed leak surveys at 

refineries and has generally found more 

leaking equipment than estimated by 

facilities. Surveys at 17 refineries across 

the country found on average that 

facilities found 1.7% of their 

components to be leaking. Where as the 

NEIC surveys found on average 5% 

leaking components. Emissions based 

on the NEIC surveys were 2.4 times as 

high as the emission estimates based on 

the facility surveys. 

Taken together, the control efficiency 

and rule effectiveness determine the 

overall program effectiveness. TCEQ’s 

addition of imputed emissions based on 

actual ambient measurements is one 

way to account for the program 

effectiveness issues described above and 

other potential problems such as leaks 

from non-traditional components such 

as heat exchanger bonnets and man-way 

covers. 

The changes to the program will make 

strides to address these issues. First, 

TCEQ has expanded the leak detection 

and repair program to include 

connectors and non-traditional 

components. This will increase the 

probability that leaks from unsurveyed 

equipment will be detected and 

repaired. Second, TCEQ is requiring, 

starting with the 2004 inventory, that all 

sources use correlation equations 

instead of assuming a control efficiency. 

Correlation equations are the most 

sophisticated approach to estimating 

emissions, short of bagging studies on 

each valve. As a result, future emission 

estimates will be based on the actual 

leaks found. In addition, the institution 

of third party audits should improve the 

performance of leak survey technicians 

so that more leaks are detected and 

repaired. Finally, more valves will be 

repaired as companies are required to 

employ ‘‘extraordinary efforts’’ to repair 

a leaking valve before allowing the 

repair to be delayed until the next 

shutdown. New technologies for repair, 

coming under the heading of 

‘‘extraordinary efforts’’ should greatly 

reduce the number of valves that go 

unrepaired. 

In summary, EPA believes that part of 

the reason it was necessary to adjust the 

base inventory to increase the emissions 

above reported levels based on ambient 

measurements, was to account for 

problems in assumptions for control 

efficiency, rule effectiveness and leaks 

from non-traditional components. The 

changes to the program will address 

each of these areas. EPA believes that 

the combination of the improvements to 

the program and the institution of third 

party audits can result in the projected 

64% reduction in emissions. The 

addition of new components to the 

program and the requirement for 

extraordinary repair effort will improve 

the control efficiency. The requirement 

for third party audits and other changes 

will improve the rule effectiveness. 

EPA’s policy on credit for rule 

effectiveness improvements requires 

that States commit to perform a study to 

determine if the rule effectiveness 

improvements are in practice realized. 

In response to comments on this issue, 

TCEQ has committed to conducting a 

rule effectiveness study based on the 

third party audit program after the 

program has progressed and data is 

available. EPA notes the first third party 

audits will be completed December 31, 

2005. EPA would expect a rule 

effectiveness study summarizing the 

results of the first third party audits 

could be completed during the 2006 

calender year. Using the rule 

effectiveness study and the results of the 

improved emission inventory estimates 

based on correlation equations, Texas 

will be able to determine if the 

emissions targets that have been 

modeled have been reached. In 

addition, this data will be useful in 

developing the 8-hour attainment plan. 

EPA is proposing to approve the 

emission reductions that have been 

projected for the improved leak 

detection and repair rules. Our approval 

is based on the improvements to the 

fugitive rule and Texas’ commitment to 

perform a rule effectiveness study and 

use improved emission inventory 

techniques to estimate future emissions 

to confirm the effectiveness of the 

program. 

8. What Are the Requirements for 

Portable Gasoline Containers? 

TCEQ has adopted standards for 

portable fuel containers sold in the State 

which provide requirements to prevent 

leaks and spills. EPA has approved the 

TCEQ rules on February 10, 2005 (70 FR 

7041). TCEQ has projected 2.9 tons/day 

58132 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

of emission reductions. We are 

proposing approval of the modeling 

with the inclusion of these projected 

emission reductions. 

C. Revised Control Measures 

1. What Control Measures Have Been 

Revised or Repealed? 

Texas has revised a number of control 

strategies that were included in the 

approved State Implementation Plan. A 

description of the revisions follows. 

Industrial NOX Controls: Texas 

revised its NOX rules to relax the 

controls from a nominal 90% control to 

80% control. Both the 90% level of 

control and the 80% level of control are 

far more stringent than the levels of 

control EPA previously approved as 

meeting the NOX RACT requirements of 

Section 182 (65 FR 53172, September 1, 

2000). Therefore, the 90% level of 

control is a discretionary control 

measure as considered in the Phase 1 

rules because the 90% level of control 

was not mandated by Subpart 2 of the 

Clean Air Act but was chosen as 

necessary for the area to demonstrate 

attainment of the 1-hour standard. 

Discretionary measures are not subject 

to the antibacksliding provisions of the 

Phase 1 rule, but any revisions of such 

measures are subject to Section 110(l) of 

the Act. In Section II.E., we discuss the 

revised plan’s compliance with Section 

110(l) of the Act. In Section II.B., we 

discuss why we believe, taken together 

with other changes, the plan continues 

to demonstrate attainment of the 1-hour 

standard. In section II.D., we explain 

why we believe this measure is not 

necessary to meet the Act’s RACM 

requirement. For the above reasons, we 

are proposing approval of the revisions 

to the TCEQ Chapter 117 rules reducing 

the stringency from a nominal 90% 

control to a nominal 80% control. 

In addition to a change in stringency 

of the rules, TCEQ made a number of 

less significant changes that are 

discussed in appendix 1 of the TSD. 

These changes include the repeal of 

outdated sections, rule clarifications, 

stylistic changes in response to Texas 

Register guidelines, minor changes to 

monitoring requirements, corrections to 

cross references and improved 

recordkeeping requirements for 

consistency with Title V requirements. 

We are also proposing approval of these 

less substantive changes. 

Vehicle Inspection and Maintenance 

Program in Three Rural Counties: TCEQ 

has dropped the requirement for I/M in 

Waller, Liberty and Chambers Counties. 

These counties are not included in the 

urbanized area and are therefore not 

required by Subpart 2 of the Act to 

implement an I/M program. Therefore, 

I/M in these three counties is a 

discretionary measure that is not subject 

to the antibacksliding provisions of the 

Phase 1 rule, but any revisions to the 

SIP approved I/M requirements must 

comply with section 110(l) of the Act. 

In Section II.E., we discuss the revised 

plan’s compliance with Section 110(l) of 

the Act. In Section II.B we discuss why 

we believe, taken together with other 

changes, the plan continues to 

demonstrate attainment of the 1-hour 

standard. In section II.D., we explain 

why we believe this measure is not 

necessary for the area to meet the Act’s 

RACM requirement. Therefore, EPA is 

proposing to approve the repeal of the 

I/M program for these three counties. 

The TCEQ also made a number of 

nonsubstantive changes to the I/M 

program that are discussed in Appendix 

2 of the TSD. These changes were 

corrections to cross references and 

stylistic changes. We are also proposing 

approval of these additional 

nonsubstantive changes. 

Removal of Small, Spark-Ignition 

Engine Operating Restrictions: TCEQ 

has dropped this requirement which 

would have prohibited commercial 

lawn services from operating during the 

morning hours. This measure is not 

required by Subpart 2 of the Clean Air 

Act. Therefore, it is a discretionary 

measure that is not subject to the 

antibacksliding provisions of the Phase 

1 rule, but any revision to the approved 

SIP must comply with section 110(l) of 

the Act. In Section II.E., we discuss the 

plan’s compliance with Section 110(l) of 

the Act. In Section II.B., we discuss why 

we believe, taken together with other 

changes in the plan, the revised plan 

continues to demonstrate attainment of 

the 1-hour standard. In section II.D., we 

explain why we believe this measure is 

not necessary to meet the Act’s RACM 

requirement. Therefore, EPA is 

proposing approval of this change. 

Speed Limit Strategy from a 55 mph 

Maximum Speed Limit to a 5 Mile 

Reduction in Speed Limits from 

Previous Levels: The Texas legislature 

repealed TCEQ’s authority to implement 

speed limits for environmental 

purposes. Texas Department of 

Transportation had already reduced 

speeds in the HGB area by 5 mph from 

70 mph to 65 mph and from 65 to 60. 

These reductions in speed limits of 5 

mph remain in place, but the reductions 

that would have been achieved by 

reducing speed limits on all roads 

further to 55 mph will not be achieved. 

Calculated using Mobile 6, the 

reductions from this measure are much 

smaller than as calculated under Mobile 

5 in the previous SIP. This measure is 

not required by Subpart 2 of the Clean 

Air Act. Therefore, it is a discretionary 

measure that is not subject to the 

antibacksliding provisions of the Phase 

1 rule, but any revision to the approved 

SIP must comply with section 110(l) of 

the Act. In Section II.E., we discuss the 

plan’s compliance with Section 110(l) of 

the Act. In Section II.B., we discuss why 

we believe, taken together with other 

changes in the plan, the revised plan 

continues to demonstrate attainment of 

the 1-hour standard. In section II.D., we 

explain why we believe this measure is 

not needed to meet the Act’s RACM 

requirement. For the above reasons, EPA 

is proposing approval of this revision of 

the State’s plan. 

Removal of the Vehicle Idling 

Restriction: This measure that would 

have prohibited prolonged idling of 

heavy duty diesel vehicles has been 

repealed. This measure is not required 

by Subpart 2 of the Clean Air Act. 

Therefore, it is a discretionary measure 

which is not subject to the 

antibacksliding provisions of the Phase 

1 rules, but any revision to the approved 

SIP must comply with section 110(l) of 

the Act. In Section II.E., we discuss the 

plan’s compliance with Section 110(l) of 

the Act. In Section II.B., we discuss why 

we believe, taken together with other 

changes in the plan, the revised plan 

continues to demonstrate attainment of 

the 1-hour standard. In section II.D., we 

explain why we believe this measure is 

not necessary to meet the Act’s RACM 

requirement. For the above reasons, we 

are proposing approval of this change. 

Revision to Delay the Compliance 

Date for Gas Fired Water Heaters and 

Small Boilers: This rule is not being 

repealed, but its compliance date has 

been delayed from December 31, 2004 to 

January 1, 2007. This rule requires new 

water heaters sold in Texas to achieve 

lower NOX emission rates. A delay in 

the compliance date results in reduced 

emission reductions because there is 

less time for old water heaters to be 

replaced with new water heaters 

through normal turnover. Texas has 

accounted for these lost reductions in its 

attainment modeling. This measure is 

not required by Subpart 2 of the Clean 

Air Act. Therefore, it is a discretionary 

measure that is not subject to the 

antibacksliding provisions of the Phase 

1 rule, but any revision to the approved 

SIP must comply with section 110(l) of 

the Act. In Section II.E., we discuss the 

plan’s compliance with Section 110(l) of 

the Act. In Section II.B., we discuss why 

we believe, taken together with other 

changes in the plan, the revised plan 

continues to demonstrate attainment of 

the 1-hour standard. In section II.D., we 

explain why we believe earlier 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58133 

implementation of this measure is not 

necessary to meet the Act’s RACM 

requirement. 

We are not proposing approval of this 

change to the rules for control of water 

heaters at this time. It is a Statewide 

rule and the changes to the rule impact 

other areas of the State and we have not 

yet analyzed the above issues in areas of 

the State other than Houston. We note 

only that the changes to the water heater 

rules do not impact the approvability of 

the Houston mid-course review SIP 

revision. 

Revisions to the Voluntary Measures: 

Texas has revised the voluntary mobile 

emissions program (VMEP) portion of 

the State Implementation Plan. This 

portion of the plan, which was 

approved in 2001, was projected to 

achieve 23 tpd of emission reduction 

through various voluntary and often 

innovative measures. Experience and 

the recalculation of the benefits with 

Mobile 6 has resulted in a much lower 

expectation for the program which now 

is expected to only achieve 10.6 tpd of 

emission reductions. The details of 

changes to the program are contained in 

appendix O of the SIP. These measures 

are not required by Subpart 2 of the 

Clean Air Act and therefore, are 

discretionary measures that are not 

subject to the antibacksliding rules 

provisions of Phase 1 rule, but revisions 

to the approved 1-hour SIP must comply 

with section 110(l) of the Act. In Section 

II.E., we discuss the plan’s compliance 

with Section 110(l) of the Act. In 

Section II.B., we discuss why we 

believe, taken together with other 

changes in the plan, the revised plan 

continues to demonstrate attainment of 

the 1-hour standard. In section II.D, we 

explain why we believe these measures 

are not necessary for the area to meet 

the Act’s RACM requirement. For the 

above reasons, EPA is proposing 

approval of the revisions to the VMEP 

measures. 

D. Reasonably Available Control 

Measures 

1. What Are the RACM Requirements? 

Section 172(c)(1) of the Clean Air Act 

requires that each nonattainment plan 

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. EPA has 

provided guidance interpreting section 

172(c)(1) of the Act. See 57 FR 13498, 

13560, April 16, 1992. In that guidance, 

EPA indicates that potentially available 

control measures, which would not 

advance the attainment date for an area 

or contribute to reasonable further 

progress, would not be considered 

RACM under the Act. EPA’s guidance 

also indicates that States should 

consider all potentially available 

measures to determine whether they are 

reasonably available for implementation 

in the area including whether or not 

they would advance attainment. 

Further, the guidance calls for states to 

indicate in their SIP submissions 

whether measures considered are 

reasonably available or not, and if so the 

measures must be adopted as RACM. 

Finally, the guidance indicates that 

States could reject potential RACM 

measures either because they would not 

advance the attainment date or would 

cause substantial widespread and longterm adverse impacts or for various 

reasons related to local conditions. See 

‘‘Guidance on Reasonably Available 

Control Measures (RACM) Requirement 

and Attainment Demonstration 

Submissions for Ozone Nonattainment 

Areas,’’ John Seitz, Director, Office of 

Air Quality Planning and Standards, 

November 30, 1999. 

2. How Has Texas Insured With This 

Plan Revision That All RACM Are Being 

Implemented? 

In EPA’s November 14, 2001 notice 

approving the plan for the HGB 

nonattainment area, EPA approved the 

analysis showing the plan was 

implementing all Reasonably Available 

Control Measures. The NOX reduction 

requirements of that plan were so 

substantial no additional RACM 

measures could be identified in time for 

adoption as a part of that plan and the 

State had to make an enforceable 

commitment to adopt additional NOX

measures which were expected to be 

feasible in the near future. Now, based 

on the findings of the mid-course 

review, Texas has determined that the 

NOX reductions necessary for 

attainment, while still substantial, are 

not as great and that control of HRVOCs 

is a more effective way of reducing 

ozone. In section II.A. of this notice, we 

discuss how EPA found that the revised 

plan for HGB will achieve attainment of 

the 1-hour standard, based on the 

controls that will be in place by the 

beginning of the ozone season of 2007. 

Both NOX and HRVOC controls, 

necessary for attainment, will be fully 

implemented the last year of the 

strategy. In the last year of the strategy, 

the point source controls alone will 

achieve an estimated 39 tpd of NOX

reductions (based on review of the 

TCEQ’s Mass Cap-and-Trade Registry). 

Reductions in on- and off-road 

emissions will also occur. Therefore, to 

advance attainment, additional 

reductions on the order of 39 tpd would 

have to be achieved before the ozone 

season of 2006. In Section 5.4 of the 

State Implementation Plan, Texas 

explains why even with the repeal and 

revision of the measures described in 

Section II.C., Texas believes the RACM 

requirement is still being met. What 

follows is a summary of EPA’s 

evaluation of each of the revisions. 

Industrial NOX Controls: TCEQ has 

relaxed the NOX rules for a number of 

NOX point source categories. The 

original controls achieved a nominal 

90% reduction in point source 

emissions, with some categories 

reducing more than 90% and some less 

than 90%. The new rules, being 

considered here today, achieve a 

nominal 80% control. It is a convenient 

short hand to refer to the control levels 

as 90% or 80% even though this does 

not accurately state the level of 

reduction for individual source 

categories. TCEQ has argued that the 

90% controls would not advance 

attainment because the current 80% 

control levels are scheduled to be 

implemented in 2007 and it would not 

be reasonable to expect that a more 

stringent 90% control could be 

implemented faster to advance 

attainment. EPA previously agreed that 

the most expeditious schedule for the 

90% controls would be by 2007. EPA 

continues to believe that to be the case 

so that implementation of 90% controls 

would not advance attainment and 

therefore is not RACM. Even at the 80% 

control level, the TCEQ rules are still 

similar in stringency to the control 

levels implemented in California which 

have generally been considered the most 

stringent in the country. (See the 

Technical Support Document for more 

information) 

Repeal of the I/M Program in 3 Rural 

Counties: Texas has chosen to reduce 

the scope of its I/M program from eight 

counties to five counties. The three 

counties that are being dropped are 

Chambers, Liberty and Waller Counties. 

These are the most rural counties in the 

nonattainment area. The program was 

scheduled to be implemented in 2005. 

Using Mobile6, Texas has estimated that 

the program would achieve 0.87 tpd of 

emission reductions which is a smaller 

reduction estimate than the Mobile 5 

estimate included in the 2000 SIP and 

is less than .2% of the projected 

emissions for the area in 2007. Because 

of the small amount of emission 

reductions, implementation of I/M in 

these three counties would not be 

58134 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

expected to advance attainment. Thus, 

EPA proposes that implementation of I/ 

M in these three counties is not required 

to meet the RACM requirement. 

Removal of Small Spark Operating 

Restrictions: This measure would 

prohibit lawn and garden service 

contractors for operation in the morning 

hours from 6 a.m. to 10 a.m.—a time 

during which emissions have been 

found to contribute most significantly to 

ozone production. This measure was 

due to be implemented in 2005. Texas 

decided that attainment could be 

reached without the implementation of 

this measure. The measure was 

estimated to achieve the equivalent of 

7.7 tons/day of NOX emission 

reductions. As such, its implementation 

would not advance the attainment date. 

Therefore, EPA believes the morning 

lawn service ban should not be 

considered a reasonably available 

control measure for the HGB area. 

Speed Limit Strategy: The approved 

SIP provides for the speed limits in the 

eight county area to be reduced to 55 

mph. Later, TCEQ decided to delay the 

implementation of the 55 mph until 

2005, but would implement speed limits 

that are 5 mph lower than the previous 

speed limits, lowering 70 mph speed 

limits to 65 mph and 65 mph limits to 

60 mph starting in 2001. In the 2004 SIP 

revision, TCEQ decided to make 

permanent the interim limits and forgo 

lowering the speed limits to 55 mph. 

Based on Mobile 6, lowering speeds all 

the way to 55 mph would be expected 

to reduce emissions 2–3 tons/day. This 

is a lower estimate of emission 

reductions than predicted by Mobile 5 

in the 2000 SIP revision. This small 

amount of emission reduction would 

not advance attainment in the Houston 

area and therefore this measure is not 

considered RACM. 

Vehicle Idling Restriction: Texas is 

dropping a rule that prohibits idling of 

heavy duty vehicles for more than five 

minutes in the Houston area. The 

measure was estimated to reduce NOX

emissions by 0.48 tpd. Texas decide that 

attainment could be reached without the 

implementation of this measure. This 

small amount of emission reduction 

would not advance attainment for the 

area and therefore should not be 

considered RACM. 

Delay in Compliance for the Water 

Heater Rule: In this case, TCEQ still 

intends to implement the rule, but has 

delayed compliance until 2007. Since 

the adoption of the current rule, two 

American National Standards Institute 

(ANSI) standards (the flammable vapor 

ignition resistance standard and the lint, 

dirt, and oil standard); the United States 

Department of Energy (DOE) energy 

efficiency standard; and the EPA 

insulation foam ban have been 

implemented. The ANSI lint, dirt, and 

oil standard and the flammable vapor 

ignition resistance standard were 

effective on July 1, 2003, and were 

established for gas-fired water heater 

safety reasons. The DOE energy 

efficiency standard was effective on 

January 20, 2004. The EPA foam ban 

was effective on January 1, 2003, and 

affects gas-fired water heaters, as water 

heater manufacturers have historically 

used hydrochlorofluorocarbon as a 

blowing agent for creating foam 

insulation. The implementation of these 

standards has delayed the progression of 

the water heater technology and design. 

Therefore, a design that meets the 10 ng/ 

J emission limit in the Texas rule will 

not be available for sale in the market 

by the January 1, 2005. 

Because the new federal standards 

affect the design of new water heaters 

and have made it impractical for the 

industry to meet Texas’s NOX limits for 

water heaters in a timely manner, EPA 

agrees that this measure is being 

implemented as expeditiously as is 

technically practicable. In other words, 

earlier implementation is not 

technically practicable and therefore, 

since it would be infeasible, it would 

not advance attainment and would not 

be RACM. 

E. Section 110(l) Analysis 

1. What Does Section 110(l) Require? 

Section 110(l) of the Clean Air Act 

says: 

‘‘Each revision to an implementation 

plan submitted by a State under this Act 

shall be adopted by such State after 

reasonable notice and public hearing. 

The Administrator shall not approve a 

revision of a plan if the revision would 

interfere with any applicable 

requirement concerning attainment and 

reasonable further progress (as defined 

in section 171), or any other applicable 

requirement of this Act.’’

2. How Has Texas Shown These 

Revisions Do Not Interfere With 

Attainment of the 8-hour Standard? 

Texas must consider whether the new 

strategy which relies on fewer 

reductions of NOX and more reductions 

of VOC will interfere with attainment or 

reasonable further progress or any other 

applicable requirement under the Act. A 

strict interpretation of this requirement 

would allow EPA to approve a SIP 

revision removing a SIP requirement 

only after determining, based on a 

completed attainment demonstration, 

that it would not interfere with 

applicable requirements concerning 

attainment and reasonable further 

progress. As discussed above, Texas has 

completed a revised attainment 

demonstration with respect to the 1- 

hour standard. Attainment 

demonstrations for the 8-hour standard 

are not due for several years. EPA 

recognizes that prior to the time areas 

are required to submit full attainment 

demonstrations for the 8-hour ozone 

standard, this strict interpretation could 

prevent any changes to the SIP control 

measures. EPA does not believe this 

strict interpretation is necessary or 

appropriate. 

Prior to the time that attainment 

demonstrations are due for the 8-hour 

ozone standard, it is unknown what 

suite of control measures a State will 

choose to adopt for a given area to attain 

that standard. For example, different 

mixes of NOX or VOC and industrial or 

mobile source controls may result in 

attainment. During this period, to 

demonstrate no interference with the 8- 

hour NAAQS, EPA believes it is 

appropriate to allow States to substitute 

equivalent emission reductions to 

compensate for the control measures 

being removed from the approved SIP. 

EPA believes preservation of the status 

quo air quality during the time new 

attainment demonstrations are being 

developed will prevent interference 

with the States’ obligations to develop 

timely attainment demonstrations and 

to attain as expeditiously as practicable. 

‘‘Equivalent’’ emission reductions 

mean reductions which result in equal 

or greater air quality benefit than those 

reductions being removed. To show the 

compensating emission reductions are 

equivalent, modeling or adequate 

justification must be provided (EPA 

Memorandum from John Calcagni, 

Director Air Quality Management 

Division, to the Air Directors in EPA 

Regions 1–10, September 4, 1992). The 

compensating emission reductions must 

represent actual, new emission 

reductions achieved in a 

contemporaneous time frame in order to 

preserve the status quo. In addition, the 

emission reductions must be permanent, 

quantifiable, and surplus to be approved 

into the SIP. 

As discussed previously, Texas has 

chosen to substitute actual, reductions 

of HRVOCs for some of the NOX

reductions in the approved SIP. This 

approach is evaluated below with 

respect section 110(l) and the criteria 

described above. 

Contemporaneous: While 

contemporaneous is not defined in the 

Clean Air Act, a reasonable 

interpretation is that the compensating 

control measures be implemented 

within one year of the time frame for the 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58135 

control measure being replaced. In this 

case, the new control measures being 

used as substitutes are being 

implemented in virtually the same time 

frames as the measures being replaced. 

The new measures have the following 

compliance dates: tighter controls on 

HRVOC fugitive emissions—March 31, 

2004, HRVOC cap-monitoring 2005, full 

cap compliance 2006, gas can rule-2007. 

The measures being replaced, which are 

listed in section II.D., with the 

exception of the vehicle idling ban, all 

had compliance dates in the approved 

SIP of 2005 or later. In particular the 

largest emission reduction change by 

far, the difference between 90% and 

80% control on NOX, was not scheduled 

to be put in place until 2007. It is worth 

noting that reductions that would have 

been achieved by controls adopted to 

meet the enforceable commitment to 

reduce NOX did not have a specified 

compliance date. The commitment only 

provided that the measures would be 

adopted by May 2004 and compliance 

would be achieved as expeditiously as 

possible but no later than the beginning 

of the ozone season in 2007. Therefore, 

it can be assumed the emission 

reductions from the NOX enforceable 

commitments, had they been 

implemented, would not have occurred 

before the 2005–2006 time frame, a time 

frame similar to that for the measures to 

control HRVOCs which Texas has 

adopted as a substitute. With regard to 

the vehicle idling restrictions, the 

compliance date for this rule was May 

of 2001. It was projected to achieve 0.48 

tpd of emission reductions. It was 

discontinued effective December 23, 

2004. The improved HRVOC fugitive 

controls which began implementation in 

March of 2004, more than offset the 

small reductions lost by the 

discontinuation of the motor vehicle 

idling program after December 23, 2004. 

Equivalent: To demonstrate that the 

emission reductions were equivalent, 

the TCEQ used the photochemical 

model to demonstrate that the total 

collection of strategies in the current SIP 

revision is equivalent or better in 8-hour 

ozone reduction effectiveness as 

compared with the total collection of 

strategies in the SIP that was approved 

in 2001 including the reductions that 

would have occurred due to measures to 

meet the enforceable commitments. 

Several 8-hour ozone metrics were 

calculated. The results indicated that 

the revised SIP is slightly more effective 

in reducing 8-hour ozone than the 

previously approved SIP in both average 

relative reduction factor (0.931 vs. 

0.940) and in average future design 

value (107 vs 108 ppb). Although some 

monitoring stations fare slightly worse 

under the new control strategy, others 

fare slightly better. In addition, for both 

peak 8-hour ozone concentration and 

exposure metrics, the benefits of the 

new strategy exceed those of the old on 

every day except September 6, where 

the old strategy is slightly better. 

Considering, the modeled predicted area 

of exceedance, however, the comparison 

is less clear-cut. The older strategy 

shows more of a benefit on six of ten 

days and the new strategy shows a 

greater benefit on three days. Both 

strategies indicate the same benefit on 

one day. In summary, EPA believes that 

the new strategy and the old strategy are 

approximately equivalent in eight hour 

ozone benefit, with the new strategy 

slightly more effective in reducing the 

peak ozone values and the old strategy 

slightly more effective in reducing the 

predicted area of exceedence. Taking all 

of the metrics into consideration and 

recognizing the uncertainties in the 

modeling, we believe that Texas has 

demonstrated that the new strategy is 

equivalent to the old strategy in 8-hour 

ozone benefit. 

Permanent: The emission reductions 

from the HRVOC rules are permanent as 

sources will have to maintain 

compliance with new measures 

indefinitely. 

Enforceable: EPA is reviewing the 

enforceability of the substitute measures 

in separate rules. The Gas Can Rule was 

approved on February 10, 2005, 70 FR 

7041. EPA has proposed approval of the 

fugitive emission controls and improved 

monitoring requirements for HRVOCs 

on April 7, 2005, 70 FR 17640 . Finally, 

concurrent with this Federal Register 

notice EPA is proposing approval of the 

HECT program. In each of these 

rulemakings, EPA will evaluate whether 

the substitute rules are enforceable, 

considering such issues as whether the 

rules have adequate test methods, 

monitoring requirements, record 

keeping requirements and whether the 

State has adequate enforcement 

authority to ensure the limits are 

achieved. As discussed elsewhere, the 

revisions to the attainment plan 

including the NOX rule repeals and 

revisions that reduce the projected 

amount on NOX emission reductions 

cannot be approved unless final 

approval of the substitute rules is 

completed. If approved, these substitute 

rules will be federally enforceable and 

enforceable by the public through 

citizen suit. 

In summary, we believe the substitute 

measures result in equivalent 8-hour 

benefit and that the new measures are 

contemporaneous, enforceable and 

permanent. Therefore, we believe 

approval of these revisions to the 

approved SIP will not interfere with 

attainment of the 8-hour standard. 

3. What About Possible Interference 

With the 1-Hour Ozone Standard? 

The 1-hour standard was revoked on 

June 15, 2005 for the HGB area. The 

approved SIP, however, committed the 

State to adopt control measures of 56 

tpd, unless the State could show that 

these NOX reductions were not needed 

for attainment of the 1-hour standard. 

We have discussed, in Section II.A., 

EPA’s evaluation of the revised 1-hour 

attainment demonstration and are 

proposing approval of that strategy as 

demonstrating attainment of the 1-hour 

standard. 

4. How Has Texas Shown These 

Revisions Do Not Interfere With Rate of 

Progress? 

Texas submitted, and EPA has 

approved, revisions to the rate of 

progress plan (February 14, 2005 70 FR 

7407) based on the revised strategy. 

These revisions will ensure that 1-hour 

ROP is met for each 3-year period out 

to the 1-hour attainment date. (See the 

Federal Register cited above for further 

explanation of the approved ROP 

demonstration.) 

5. Do These Revisions Interfere With 

Attainment of Other Standards Besides 

Ozone? 

The HGB area currently meets all 

other National Ambient Air Quality 

Standards besides ozone. The plan 

revisions being considered would not be 

expected to impact compliance with the 

CO, SO2 or lead NAAQs as these 

pollutants are not affected by these 

rules. 

The revisions to the NOX rules do 

affect emissions of NO2 and thus could 

potentially impact attainment with the 

NO2 standard. The HGB area, however, 

meets the NO2 standard at today’s level 

of NO2 emissions and the revised plan 

will still reduce NO2 emissions 

considerably from today’s levels and 

thus will not interfere with maintenance 

of the NO2 standard. 

Similarly, the HGB area currently 

meets the NAAQS for PM fine. NOX and 

VOCs are precursors to the formation of 

PM fine. The revised plan will result in 

additional NOX and VOC reductions 

beyond today’s levels. Therefore, the 

revised plan will not interfere with the 

continued attainment of the PM fine 

standard. 

58136 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

6. Do the Revisions Interfere With Any 

Other Applicable Requirements of the 

Act? 

Section 110(l) applies to all 

requirements of the Act. Below are 

requirements potentially affected by 

TCEQ’s rule change and a brief 

discussion of EPA’s analysis. 

Reasonably Available Control 

Technology (RACT) requirements: EPA 

has previously approved the NOX and 

VOC rules in the HGB area as meeting 

the Act’s RACT requirements. The 

revised NOX rules remain substantially 

more stringent than the previously 

approved RACT requirements. The new 

HRVOC rules build on the previously 

approved RACT requirements. In 

addition, these revisions do not impact 

the major sources applicability cutoffs. 

Therefore, these revisions do not 

interfere with the implementation of 

RACT. 

Inspection and maintenance programs 

(I/M): This revision drops three counties 

from the I/M program. These counties 

are not included in the urbanized area 

as defined by the Census Bureau. Thus, 

I/M is not required to be implemented 

in these counties and thus these 

revisions do not interfere with meeting 

the I/M requirements of the Act. 

Air Toxics: There are no federal 

ambient standards for air toxics and 

these rules do not impact compliance 

with any federal MACT standards so 

these rule revisions do not interfere 

with compliance with any air toxics 

standards. We note that air toxic levels 

of butadiene and formaldehyde are 

expected to decrease as a result of the 

revised plan. Butadiene emissions are 

directly regulated by the new HRVOC 

rules. Formaldehyde is formed from 

ethylene in the photochemical reactions 

leading to ozone. 

F. Enforceable Commitments 

1. What Is an Enforceable Commitment? 

An enforceable commitment is a 

written commitment that is approved 

into the SIP that is enforceable against 

the State. In the SIP approved in 

November 2001, there were enforceable 

commitments to achieve additional NOX

reductions and enforceable 

commitments to incorporate the latest 

information into the SIP. 

To be enforceable, commitments must 

be approved as part of the SIP and, 

therefore, the State must have given 

notice and taken comment on the 

commitment, held a public hearing and 

submitted it as a SIP revision. The 

commitments must be specific as to the 

state agency’s future plans for adoption 

of specified control measures. The dates 

for implementation of, or compliance 

with, the future to-be-adopted specified 

control measures must be included in 

the commitments and be as expeditious 

as practicable. If the State does not 

follow through with the commitment, 

EPA can find that the State failed to 

implement the SIP. Further, the public 

can seek enforcement of the obligations 

under Section 304(a) of the CAA. 

2. What Were the Enforceable 

Commitments in the 2001 Approved SIP 

and Have They Been Fulfilled? 

In the approved SIP, there are a 

number of enforceable commitments. In 

this section we evaluate whether these 

enforceable commitments have been 

met. The State made the following 

commitments which were approved in 

the November 2001 Federal Register. 

• 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 recommended mid-course 

corrective actions, to the EPA by May 1, 

2004. 

Discussion: Texas provided the midcourse review in the December 2004 

submission. It included new modeling 

with new more recent episodes based on 

the Texas 2000 study. Virtually all of 

the inputs to the model were updated 

and improved, making the 2004 SIP the 

best modeling ever performed for the 

Houston area. Additionally, the State 

submitted control measures that, based 

on the demonstration, will result in 

attainment of the 1-hour standard as 

expeditiously as practicable. Therefore, 

EPA believes the commitment for a mid 

course review has been satisfied. 

• To perform new mobile source 

modeling for the HG area, using 

MOBILE6, EPA’s on-road mobile 

emissions factor computer model, 

within 24 months of the model’s release. 

Discussion: The midcourse review 

modeling employed MOBILE6 for the 

on-road mobile source inputs satisfying 

this commitment. 

• If a transportation conformity 

analysis is to be performed between 12 

months and 24 months after the 

MOBILE6 release, transportation 

conformity will not be determined until 

Texas submits an MVEB which is 

developed using MOBILE6 and which 

we find adequate. 

Discussion: This commitment was not 

applicable because transportation 

conformity was not performed during 

the time period. 

• To adopt rules that achieve at least 

the additional 56 tpd of NOX emission 

reductions that are needed for the area 

to show attainment of the 1-hour ozone 

standard. 

See below. 

• To adopt measures to achieve 25% 

of the needed additional reductions (56 

tpd) and submit those adopted measures 

to EPA as a SIP revision by December 

2002. 

Discussion: This commitment 

required TCEQ to find measures to 

achieve an additional 14 tons/day of 

NOX emission reductions and to submit 

adopted control measures by December 

2002. In the January 28, 2003 

submission, TCEQ provided the 

demonstration that the TERP program 

meets EPA’s requirements as an 

economic incentive program and will 

achieve the required 14 tons/day of 

emissions reductions. EPA has 

approved the TERP program in a 

separate Federal Register action which 

discusses how the TERP program meets 

the EIP requirements (August 19, 2005, 

70 FR 48647 ). Through the attainment 

year of 2007, 38.8 tons/day of emission 

reductions are projected for the TERP 

program based on a $5,000/ton cost 

effectiveness. The total obligation for 

emission reductions from TERP is 32.9 

tpd. TERP originally replaced two 

measures: a morning construction ban 

(6.7 tpd NOX equivalent) and 

accelerated introduction of Tier II/III 

equipment 12.2 tpd). After allocating 

18.9 tpd from TERP to replace these two 

measures, the program still is projected 

to produce an additional 19.9 tpd of 

reductions which is sufficient to 

provide the additional 14 tpd of 

emissions reductions needed to meet 

the enforceable commitment. Thus, EPA 

believes the enforceable commitment to 

achieve 25% of the 56 tpd of NOX

reductions has been satisfied. 

We note two developments with the 

program. The average cost effectiveness 

of TERP projects, to date, is $5500/ton 

and the Texas legislature moved to cut 

some of the funding for the program in 

the last session. TCEQ may have to shift 

some of the TERP funding from other 

areas such as Corpus Christi or Victoria, 

which currently meet the 8-hour ozone 

standard to the HGB area to insure that 

the emission reduction targets are met. 

• To adopt measures for the 

remaining needed additional reductions 

and submit these adopted measures to 

EPA as a SIP revision by May 1, 2004. 

Discussion: Texas determined that 

these additional NOX reductions would 

not be necessary for the area to attain. 

Instead, as discussed elsewhere in this 

document, TCEQ has instead adopted 

and has begun implementing a strategy 

to reduce emissions of HRVOCs. EPA 

believes that the new strategy will attain 

the one-hour standard. This is further 

Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 58137 

discussed in Section II.B. regarding the 

review of the attainment demonstration 

and Section II.E regarding whether 

section 110(l) of the Act has been met. 

• That the rules will be adopted as 

expeditiously as practicable and the 

compliance dates will be expeditious. 

Discussion: TCEQ adopted its 

measures for the control of HRVOC first 

in 2002 and has revised them three 

times since then. The compliance dates 

in the rules are based on the need to 

develop monitoring plans, quality 

assurance/quality control programs, 

install the monitors, and develop 

control plans based on the monitoring 

results. EPA believes that the 

implementation of these new measures 

is as expeditious as practicable. 

• That the State would concurrently 

revise the Motor Vehicle Emissions 

Budgets (MVEBs) and submit them as a 

revision to the attainment SIP if 

additional control measures reduce onroad motor vehicle emissions. Texas 

stated that measures which could limit 

future highway construction, such as 

growth restrictions, may not be 

included. 

Discussion: Texas has revised the 

mobile source budget to account for 

TERP reductions and other adjustments 

to the mobile source emissions 

estimates. 

Summary: Based on the above 

analysis, we propose that TCEQ has 

satisfied the requirements of the 

enforceable commitments contained in 

the approved HGB SIP. 

G. Motor Vehicle Emissions Budgets 

1. What Is a Motor Vehicle Emissions 

Budget and Why Is It Important? 

The MVEB is the level of total 

allowable on-road emissions established 

by a control strategy implementation 

plan or maintenance plan. In this case, 

the MVEB establishes the maximum 

level of on-road emissions that can be 

produced in 2007, when considered 

with emissions from all other sources, 

which demonstrate attainment of the 

NAAQS. It is important because the 

MVEB is used to determine the 

conformity of transportation plans and 

programs to the SIP, as described by 

section 176(c)(2)(A) of the Act. 

2. What Are the Motor Vehicle 

Emissions Budgets Being Proposed for 

Approval? 

The MVEBs established by this plan 

and that the EPA is proposing to 

approve are contained in Table 2. The 

development of the MVEBs are 

discussed in section 3.5 of the SIP and 

reviewed in the TSD. We are proposing 

approval because we find the MVEB to 

be consistent with the attainment plan. 

TABLE 2.—2007 ATTAINMENT YEAR

MOTOR VEHICLE EMISSIONS BUDGETS

[Tons per day] 

Pollutant 2007 

VOC ................................................ 89.99 

NOX ................................................ 186.13 

III. General Information 

A. Tips for Preparing Your Comments 

When submitting comments, 

remember to: 

1. Identify the rulemaking by File ID 

number and other identifying 

information (subject heading, Federal 

Register date and page number). 

2. Follow directions—The agency may 

ask you to respond to specific questions 

or organize comments by referencing a 

Code of Federal Regulations (CFR) part 

or section number. 

3. Explain why you agree or disagree; 

suggest alternatives and substitute 

language for your requested changes. 

4. Describe any assumptions and 

provide any technical information and/ 

or data that you used. 

5. If you estimate potential costs or 

burdens, explain how you arrived at 

your estimate in sufficient detail to 

allow for it to be reproduced. 

6. Provide specific examples to 

illustrate your concerns, and suggest 

alternatives. 

7. Explain your views as clearly as 

possible, avoiding the use of profanity 

or personal threats. 

8. Make sure to submit your 

comments by the comment period 

deadline identified. 

B. Submitting Confidential Business 

Information (CBI) 

Do not submit this information to EPA 

through regulations.gov or e-mail. 

Clearly mark the part or all of the 

information that you claim to be CBI. 

For CBI information in a disk or CD 

ROM that you mail to EPA, mark the 

outside of the disk or CD ROM as CBI 

and then identify electronically within 

the disk or CD ROM the specific 

information that is claimed as CBI). In 

addition to one complete version of the 

comment that includes information 

claimed as CBI, a copy of the comment 

that does not contain the information 

claimed as CBI must be submitted for 

inclusion in the official file. Information 

so marked will not be disclosed except 

in accordance with procedures set forth 

in 40 CFR part 2. 

IV. Statutory and Executive Order 

Reviews 

Under Executive Order 12866 (58 FR 

51735, October 4, 1993), this proposed 

action is not a ‘‘significant regulatory 

action’’ and therefore is not subject to 

review by the Office of Management and 

Budget. For this reason, this action is 

also not subject to Executive Order 

13211, ‘‘Actions Concerning Regulations 

That Significantly Affect Energy Supply, 

Distribution, or Use’’ (66 FR 28355, May 

22, 2001). This proposed action merely 

proposes to approve state law as 

meeting Federal requirements and 

imposes no additional requirements 

beyond those imposed by state law. 

Accordingly, the Administrator certifies 

that this proposed rule will not have a 

significant economic impact on a 

substantial number of small entities 

under the Regulatory Flexibility Act (5 

U.S.C. 601 et seq.). Because this rule 

proposes to approve pre-existing 

requirements under state law and does 

not impose any additional enforceable 

duty beyond that required by state law, 

it does not contain any unfunded 

mandate or significantly or uniquely 

affect small governments, as described 

in the Unfunded Mandates Reform Act 

of 1995 (Pub. L. 104–4). 

This proposed rule also does not have 

tribal implications because it will not 

have a substantial direct effect on one or 

more Indian tribes, on the relationship 

between the Federal Government and 

Indian tribes, or on the distribution of 

power and responsibilities between the 

Federal Government and Indian tribes, 

as specified by Executive Order 13175 

(65 FR 67249, November 9, 2000). This 

action also does not have Federalism 

implications because it does not have 

substantial direct effects on the States, 

on the relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132 (64 FR 43255, 

August 10, 1999). This action merely 

proposes to approve a state rule 

implementing a Federal standard, and 

does not alter the relationship or the 

distribution of power and 

responsibilities established in the Clean 

Air Act. This proposed rule also is not 

subject to Executive Order 13045 

‘‘Protection of Children from 

Environmental Health Risks and Safety 

Risks’’ (62 FR 19885, April 23, 1997), 

because it is not economically 

significant. 

In reviewing SIP submissions, EPA’s 

role is to approve state choices, 

provided that they meet the criteria of 

the Clean Air Act. In this context, in the 

absence of a prior existing requirement 

for the State to use voluntary consensus 

standards (VCS), EPA has no authority 

to disapprove a SIP submission for 

failure to use VCS. It would thus be 

58138 Federal Register / Vol. 70, No. 192 / Wednesday, October 5, 2005 / Proposed Rules 

inconsistent with applicable law for 

EPA, when it reviews a SIP submission, 

to use VCS in place of a SIP submission 

that otherwise satisfies the provisions of 

the Clean Air Act. Thus, the 

requirements of section 12(d) of the 

National Technology Transfer and 

Advancement Act of 1995 (15 U.S.C. 

272 note) do not apply. This proposed 

rule does not impose an information 

collection burden under the provisions 

of the Paperwork Reduction Act of 1995 

(44 U.S.C. 3501 et seq.). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Carbon monoxide, 

Incorporation by reference, 

Intergovernmental relations, Nitrogen 

dioxide, Ozone, Particulate matter, 

Reporting and recordkeeping 

requirements, Volatile organic 

compounds. 

Authority: 42 U.S.C. 7401 et seq. 

Dated: September 27, 2005. 

Richard Greene, 

Regional Administrator, Region 6. 

[FR Doc. 05–19994 Filed 10–4–05; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[R06–OAR–2005–TX–0033; FRL–7981–2] 

Approval and Promulgation of Air 

Quality Implementation Plans; Texas; 

Highly Reactive Volatile Organic 

Compound Emissions Cap and Trade 

Program for the Houston/Galveston/ 

Brazoria Ozone Nonattainment Area 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: EPA is proposing to approve 

revisions to the Texas State 

Implementation Plan concerning the 

Highly Reactive Volatile Organic 

Compound Emissions Cap and Trade 

Program for the Houston/Galveston/ 

Brazoria ozone nonattainment area. 

These revisions were adopted by the 

Texas Commission on Environmental 

Quality on December 01, 2004, as new 

sections 101.390–101.394, 101.396, 

101.399–101.401, and 101.403, and 

submitted to EPA as a SIP revision on 

December 17, 2004. In related 

rulemakings today, EPA is also 

proposing approval of additional 

revisions to the Texas State 

Implementation Plan. 

DATES: Comments must be received on 

or before November 4, 2005. 

ADDRESSES: Submit your comments, 

identified by Regional Material in 

EDocket (RME) ID No. R06–OAR–2005–

TX–0033, by one of the following 

methods: 

• Federal eRulemaking Portal: http:// 

www.regulations.gov. Follow the on-line 

instructions for submitting comments. 

• Agency Web site: http:// 

docket.epa.gov/rmepub/. RME, EPA’s 

electronic public docket and comment 

system, is EPA’s preferred method for 

receiving comments. Once in the 

system, select ‘‘quick search,’’ then key 

in the appropriate RME Docket 

identification number. Follow the online instructions for submitting 

comments. 

• U.S. EPA Region 6 ‘‘Contact Us’’

Web site: http://epa.gov/region6/ 

r6coment.htm. Please click on ‘‘6PD’’

(Multimedia) and select ‘‘Air’’ before 

submitting comments. 

• E-mail: Mr. David Neleigh at 

neleigh.david@epa.gov. Please also cc 

the person listed in the FOR FURTHER

INFORMATION CONTACT section below. 

• Fax: Mr. David Neleigh, Chief, Air 

Permitting Section (6PD–R), at fax 

number 214–665–6762. 

• Mail: Mr. David Neleigh, Chief, Air 

Permitting Section (6PD–R), 

Environmental Protection Agency, 1445 

Ross Avenue, Suite 1200, Dallas, Texas 

75202–2733. 

• Hand or Courier Delivery: Mr. 

David Neleigh, Chief, Air Permitting 

Section (6PD–R), Environmental 

Protection Agency, 1445 Ross Avenue, 

Suite 1200, Dallas, Texas 75202–2733. 

Such deliveries are accepted only 

between the hours of 8 a.m. and 4 p.m. 

weekdays except for legal holidays. 

Special arrangements should be made 

for deliveries of boxed information. 

Instructions: Direct your comments to 

RME ID No. R06–OAR–2005–TX–0033. 

EPA’s policy is that all comments 

received will be included in the public 

file without change, and may be made 

available online at http:// 

docket.epa.gov/rmepub/, including any 

personal information provided, unless 

the comment includes information 

claimed to be Confidential Business 

Information (CBI) or other information 

the disclosure of which is restricted by 

statute. Do not submit information 

through RME, regulations.gov, or e-mail 

if you believe that it is CBI or otherwise 

protected from disclosure. The EPA 

RME website and the Federal 

regulations.gov are ‘‘anonymous access’’

systems, which means EPA will not 

know your identity or contact 

information unless you provide it in the 

body of your comment. If you send an 

e-mail comment directly to EPA without 

going through RME or regulations.gov, 

your e-mail address will be 

automatically captured and included as 

part of the comment that is placed in the 

public file and made available on the 

Internet. If you submit an electronic 

comment, EPA recommends that you 

include your name and other contact 

information in the body of your 

comment and with any disk or CD–ROM 

you submit. If EPA cannot read your 

comment due to technical difficulties 

and cannot contact you for clarification, 

EPA may not be able to consider your 

comment. Electronic files should avoid 

the use of special characters, any form 

of encryption, and be free of any defects 

or viruses. Guidance on preparing 

comments is given in the 

SUPPLEMENTARY INFORMATION section of 

this document under the General 

Information heading. 

Docket: All documents in the 

electronic docket are listed in the RME 

index at http://docket.epa.gov/rmepub/. 

Although listed in the index, some 

information is not publicly available, 

i.e., CBI or other information the 

disclosure of which is restricted by 

statute. Certain other material, such as 

copyrighted material, is not placed on 

the Internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available either electronically in RME or 

in the official file, which is available at 

the Air Permitting Section (6PD–R), 

Environmental Protection Agency, 1445 

Ross Avenue, Suite 700, Dallas, Texas 

75202–2733. The file will be made 

available by appointment for public 

inspection in the Region 6 FOIA Review 

Room between the hours of 8:30 am and 

4:30 pm weekdays except for legal 

holidays. Contact the person listed in 

the FOR FURTHER INFORMATION CONTACT

paragraph below to make an 

appointment. If possible, please make 

the appointment at least two working 

days in advance of your visit. There will 

be a 15 cent per page fee for making 

photocopies of documents. On the day 

of the visit, please check in at the EPA 

Region 6 reception area at 1445 Ross 

Avenue, Suite 700, Dallas, Texas. 

The State submittal is also available 

for public inspection at the State Air 

Agency listed below during official 

business hours by appointment: Texas 

Commission on Environmental Quality, 

Office of Air Quality, 12124 Park 35 

Circle, Austin, Texas 78753. 

FOR FURTHER INFORMATION CONTACT: Ms. 

Adina Wiley, Air Permitting Section 

(6PD–R), Environmental Protection 

Agency, Region 6, 1445 Ross Avenue, 

Suite 700, Dallas, Texas 75202–2733, 

telephone (214) 665–2115; fax number