Technical Support Document

August 2014

Revisions to Texas SIP to Control Volatile Organic Compound Emissions from Storage Tanks

Background

Under the Clean Air Act (CAA), EPA promulgated an 8-hour ozone standard of 0.08 parts per million 

(ppm), which is more protective than the previous 1-hour ozone standard (62 FR 38855, July 18, 1997). 

On April 30, 2004, EPA published designations and classifications for the 1997 8-hour ozone standard 

(69 FR 23858). The Dallas-Fort Worth 1997 ozone nonattainment area (DFW area), which consists of 

Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall and Tarrant Counties, was initially 

classified as a moderate ozone nonattainment area. The DFW area was reclassified as a serious ozone 

nonattainment for the 1997 ozone standard (75 FR 79302, December 20, 2010). The HoustonGalveston-Brazoria ozone nonattainment area (HGB area) consists of Brazoria, Chambers, Fort Bend, 

Galveston, Harris, Liberty, Montgomery and Waller counties. The HGB area is classified as a severe 

ozone nonattainment for the 1997 ozone NAAQS (73 FR 56983, October 1, 2008). The Beaumont-Port 

Arthur area (BPA area) consists of Hardin, Jefferson, and Orange Counties and was redesignated to 

attainment for the 1997 ozone standard (75 FR 64675, October 20, 2010).

Volatile organic compounds (VOCs) and oxides of nitrogen (NOx) are known as “ozone precursors”, as 

they react with oxygen and sunlight to form ozone. Motor vehicle exhaust and industrial emissions, 

gasoline vapors and chemical solvents emit NOx and VOCs. Controlling sources of NOx and VOC 

emissions can lower ozone levels in the ambient air.

Sections 172(c)(1) and 182 of the Clean Air Act require ozone nonattainment areas that are classified as 

moderate or above for ozone nonattainment to adopt Reasonably Available Control Technology (RACT) 

requirements for sources that are subject to Control Techniques Guidelines (CTGs) issued by EPA and 

for “major sources” of volatile organic compounds (VOCs) and nitrogen oxides (NOx). Major sources 

for areas classified as serious are those that have the potential to emit 50 tons per year (tpy) of VOCs or 

NOx (CAA 182(c)). RACT is defined as the lowest emissions limitation that a particular source is 

capable of meeting by the application of control technology that is reasonably available considering 

technological and economic feasibility (44 FR 53762, September 17, 1979). 

EPA has issued a number of CTGs and Alternative Control Technique (ACT) Guidelines to assist States 

in implementing RACT requirements. These documents are available at 

www.epa.gov/airquality/ozonepollution/SIPToolkit/ctgs.html and provide information on the available 

control technology for various source categories. CTGs provide control information that provides a 

“presumptive norm” for RACT for particular source categories. State rules that conform to the 

“presumptive norm” established in the CTG have generally been approved as RACT. 

Two CTGs and one ACT pertain to the VOC storage tank category:

• Control of Volatile Organic Emissions from Storage of Petroleum Liquids in Fixed-Roof Tanks

(EPA-450/2-77-036, December 1977)

• Control of Volatile Organic Emissions from Petroleum Liquid Storage in External Floating Roof 

Tanks (EPA-450/2-78-047, December 1978)
• Alternative Control Techniques Document – Volatile Organic Liquid Storage In Floating and 

Fixed Roof Tanks (EPA-453/R-94-001, January 1994)

EPA previously found that the Texas rules meet RACT requirements for storage tanks in the HGB area, 

most recently in 2010 (75 FR 15348, March 29, 2010). EPA also previously found that Texas rules for 

storage tanks met RACT requirements for the DFW area (64 FR 3841, January 26, 1999 and 74 FR 

1903, January 14, 2009).

SIP Revision Adopted on December 7, 2011 and Submitted to EPA on January 12, 2012

On December 7, 2011, the Texas Commission on Environmental Quality (TCEQ) adopted a revision to 

the SIP and submitted it to EPA on January 12, 2012. The revision pertains to VOC control 

requirements for storage tanks in the DFW area, the HGB area, the BPA area and Aransas, Bexar, 

Calhoun, El Paso, Gregg, Matagorda, Nueces, San Patricio, Travis and Victoria Counties. On January 

17, 2012, TCEQ submitted the revised SIP to EPA. The State submittal can be found in the electronic 

docket (www.regulations.gov, Docket number EPA-R06-OAR-2012-0096). As documented in the 

submittal, Texas provided notice of the proposed revisions and public hearings in Texas newspapers and 

the Texas Register. Public hearings were held in Arlington, Austin and Houston.

The revision amended Title 30, Chapter 115 of the Texas Administrative Code (30 TAC 115) to revise 

§§115.110, 115.112 - 115.117, and 115.119 and add new §§115.111 and 115.118. Table 1 lists the areas 

covered by the revision and the applicable sections of 30 TAC 115, Subchapter B, Division 1 (Storage 

of Volatile Organic Compounds). A discussion of the changes by TCEQ can be found in Appendix A –

Excerpt from December 23, 2011 Texas Register. The final adopted rule can be found in Appendix B –

30 TAC 115, Subchapter B, Division 1 (Storage of Volatile Organic Compounds).

Table 1. Areas covered by 30 TAC 115, Subchapter B, Division 1

Area Applicable 30 TAC Section

DFW and HGB 115.110, 115.111(a), 115.112(e), 115.113, 115.114(a), 

115.115(a), 115.116(a), 115.117, 115.118(a), 115.119 

BPA, El Paso County 115.110, 115.111(a), 115.112(a), 115.113, 115.114(a), 

115.115(a), 115.116(a), 115.117, 115.118(a), 115.119

El Paso County 115.110, 115.111(a), 115.112(a), 115.113, 115.114(a), 

115.115(a), 115.116(a), 115.117, 115.118(a), 115.119

Gregg, Nueces, and Victoria Counties 115.110, 115.111(b), 115.112(b), 115.113, 115.114(b), 

115.115(b) (Victoria County only), 115.116(b), 115.118(b), 

115.119

Aransas, Bexar, Calhoun, Gregg, 

Matagorda, San Patricio and Travis 

Counties

115.110, 115.111(c), 115.112(c), 115.113, 115.114(c), 

115.119
Evaluation of Revision

Review of the Revision

Review of the revision found the following that in the DFW area the amendments to the SIP

• Added a new requirement for control of VOC flash emissions from storage tanks in the DFW 

area that might otherwise emit 50 tpy of VOC or more

• Added new requirements for low-leaking storage tank fittings in DFW 

• Added new requirements to limit situations when a floating roof storage tank is allowed to emit 

VOCs because the roof is not floating on the stored VOC liquid

For the DFW and HGB areas the revision also adds a requirement that the vapor recovery unit used for 

VOC control must be designed to process all VOC vapor generated by the maximum crude oil and 

condensate throughput of the storage tank and must transfer recovered vapors to a pipe or container that 

is vapor-tight.

VOC flash emissions occur during transfer of the VOCs from a higher pressure storage tank to a lower 

pressure tank, reservoir, or other container. Floating roof landing loss emissions occur when the liquid 

level in a floating roof tank is lowered and the roof rests (lands) on the legs, or supports, rather than on

the liquid, severely limiting the VOC control efficiency of the floating roof. The requirements to control 

flash emissions, use low-leaking tank fittings and further limit emissions from floating roof storage 

tanks were previously implemented in the HGB area and approved by EPA as RACT (75 FR 15348, 

March 29, 2010).

The review also found that in the DFW, HGB and BPA areas and in El Paso, Gregg, Nueces and 

Victoria Counties the amendments to the SIP

• Add an explicit requirement that any flare used for control must be designed and operated 

according to 40 CFR §60.18(b) - (f) as amended through December 22, 2008 (115.112(a)(3), 

115.112(b)(1), 115.112(e)(3)(C))

• Improve monitoring and testing to ensure effectiveness of VOC controls

While the VOC control requirements for storage tanks also apply in Aransas, Bexar, Calhoun, 

Matagorda, San Patricio and Travis Counties, review of the revision found that it did not substantially 

change requirements for these counties.

Appendix A discusses all the rule changes. The final adopted rule submitted to EPA can be found in 

Appendix B.

EPA has previously found that the Texas rules meet RACT requirements for floating and fixed roof 

tanks in the HGB area, most recently in 2010 (75 FR 15348, March 29, 2010). As shown in the table 2, 

these revisions improve the rules for controlling VOCs from storage tanks. With these improvements, 

the rules will continue to ensure the CAA RACT requirements are met. 
Table 2. Summary of Substantive Changes in SIP Revision for 30 TAC 115

Subchapter B, Division 1, Storage of Volatile Organic Compounds

Section 

Amended

Amendment Comments

115.110

Applicability 

and Definitions 

Changed title (formerly Definitions) and added 

language on areas of applicability: DFW, HGB, 

BPA, and Aransas, Bexar, Calhoun, El Paso, 

Gregg, Matagorda, Nueces, San Patricio, Travis

and Victoria Counties. Added definitions for 

Storage capacity, Storage tank and Vapor recovery 

unit.

Improves clarity.

115.111

Exemptions

Exemptions moved from 115.117. DFW: The rule 

revisions provide an exemption from the new 

controls on flash emissions for a storage tank or 

tank battery in the DFW area with a condensate 

throughput exceeding 3,000 barrels per year on a 

rolling 12-month basis from the requirement in 

§115.112(e)(4), to control flashed gases if the 

owner or operator demonstrates, using the test 

methods specified in §115.117, that uncontrolled 

VOC emissions from the individual storage tank or 

from the aggregate of storage tanks in a tank 

battery are less than 50 tpy on a rolling 12-month 

basis (115.111(a)(10)). A similar exemption with a 

threshold of 25 tpy was added in case the DFW 

area is reclassified to severe (115.111(a)(11)).

CAA 182(c) sets the serious 

area major stationary source 

threshold to 50 tpy of VOC. 

Consistent with this the 

revision lowers the stationary 

source threshold for major 

stationary sources in the DFW 

area. As RACT is required for 

major stationary sources in 

DFW that emit 50 tpy or more

the exemption is allowed. 

In our approval of the 

previous revision, which 

included exemptions, we 

noted that it improved the 

TCEQ rules and that our 

approval would not interfere 

with any applicable 

concerning attainment or any 

other applicable requirement 

of the CAA including RACT 

requirements as required by 

CAA 110(l). (See the 

Technical Support Document 

for e-docket EPA-R06-OAR2007-0526 in 

www.regulations.gov).

115.112 

Control 

Requirements

DFW: New requirements added for 1) control of 

VOC flash emissions from storage tanks in the 

DFW area that might otherwise emit 50 tpy of 

VOC or more (115.112(e)(1)), 2) low-leaking 

storage tank fittings (115.112(e)(2)(A-J), and 3) 

limiting situations when a floating roof storage 

tank is allowed to emit VOCs because the roof is 

Additional control for major 

stationary sources in the DFW 

area. Control was previously 

found to be RACT in the 

HGB area.

The vapor recovery unit 

requirement helps ensure it 

will effectively control 
not floating on the stored VOC liquid

(115.112(e)(2)(I)).

DFW and HGB: requirement added that the vapor 

recovery unit must be designed to process all VOC 

vapor generated by the maximum crude oil and 

condensate throughput of the storage tank and 

must transfer recovered vapors to a pipe or 

container that is vapor-tight (115.112(e)(3)(B)).

DFW, HGB, BPA, and El Paso, Gregg, Nueces 

and Victoria Counties: explicit requirement that 

any flare used for control must be designed and 

operated according to 40 CFR §60.18(b) - (f) as 

amended through December 22, 2008 

(115.112(a)(3), 115.112(b)(1), 115.112(e)(3)(C)).

emissions. For DFW and 

HGB the additional vapor 

recovery unit requirement is 

an improvement to help 

ensure that vapor recovery 

units will function effectively 

to capture and transfer the 

VOC emissions from a 

storage tank under normal 

operating conditions.

The flare requirement is an 

improvement to the VOC 

control requirement.

115.113

Alternate 

Control 

Requirements

No change in approved language.

115.114

Inspection 

Requirements

DFW: updated so that the secondary seal gap 

measurement requirements are the same as for 

HGB (115.114(a)(2), 115.114(a)(3) and 

115.114(a)(4); references to 115.112(e)(2)(F) and 

(G)).

Consistent with additional 

requirements for DFW.

115.115

Monitoring 

Requirements 

Moves the monitoring requirements that were 

previously located at 115.116. DFW, HGB, BPA, 

and El Paso County: clarifying language added for 

monitoring carbon adsorption systems to ensure 

effectiveness of (115.115(a)(3)).

DFW and HGB: added specificity to the 

requirement for continuous monitoring of a vapor 

recovery unit to demonstrate effectiveness 

(115.115(a)(5); reference to 115.112(e)(3)).

DFW, HGB, BPA, El Paso County and Victoria 

County: allows for monitoring of a carbon 

adsorption unit using EPA method 21 once every 7 

days to ensure that it is working effectively 

(115.115(a)(3)(A) and 115.115(b)(3)).

Improves monitoring to 

ensure effectiveness of 

controls.

115.116

Testing 

Requirements

DFW, HGB, BPA, and El Paso County: specified 

testing requirements for 1) an initial control 

efficiency test for vapor control systems that are 

not a vapor recovery unit or a flare, 2) retesting for 

control systems that are modified in a way that 

could decrease control efficiency, and 3) design 

verification tests of 40 CFR 60.18(f) (115.116(a)).

Gregg, Nueces and Victoria Counties: Clarifying 

language added for 1) an initial control efficiency 

Improves testing to ensure 

effectiveness of controls.
test for vapor control systems that are not a vapor 

recovery unit or a flare and 2) design verification 

tests of 40 CFR 60.18(f) (115.116(b)).

115.117

Approved Test 

Methods

Test methods previously located in 115.115 are 

moved to this section. DFW, HGB, BPA, and El 

Paso, Gregg, Nueces and Victoria Counties: an 

allowance added for use of another test method if 

its validated by 40 CFR 63, Appendix A, Test 

Method 301 and approved by the TCEQ Executive 

Director (115.117(10)). 

40 CFR 63, Appendix A, Test 

Method 301 is EPA’s 

procedures to validate an 

alternative test method.

115.118

Recordkeeping 

Requirements

Recordkeeping requirements that were previously 

in 115.116 are moved to this section. DFW, HGB, 

BPA, and El Paso County: 1) clarification was 

added that owner/operators claiming an exemption 

in 115.111 must maintain sufficient records to 

show the exemption is allowed (115.118(a)(1)), 2) 

recordkeeping was expanded for carbon adsorption 

systems (115.118(a)(4)(C)) and 3) an allowance 

was added for storing records offsite, if they can 

be provided for review in 24 hours 

(115.118(a)(5)). DFW: Recordkeeping 

requirements for HGB were added 

(115.118(a)(6)). 

Recordkeeping was improved. 

TCEQ noted that offsite 

storage of records provides 

flexibility to owners/operators 

with unstaffed locations not 

equipped for record storage.

115.119

Compliance 

Schedules

DFW: Added a provision that if compliance would 

require emptying and degassing of the storage 

tank, compliance can be delayed until the next 

time the storage tank is emptied and degassed, but 

no later than December 1, 2021

(115.119(b)(1)(A)). Other compliance dates have 

passed.

The DFW provision is similar 

to one previously approved 

for HGB which allowed delay 

until the next time the storage 

tank is emptied and degassed, 

but no later than January 1, 

2017. By allowing the delay, 

additional emissions from 

emptying and degassing the 

tanks to install controls may 

be avoided. 

CAA 110(l) Analysis 

CAA section 110(l) requires that a SIP revision submitted to EPA be adopted after reasonable notice and 

public hearing. Section 110(l) also requires that we not approve a SIP revision if the revision would 

interfere with any applicable requirement concerning attainment and reasonable further progress, or any 

other applicable requirement of the CAA.

Texas adopted the SIP revision after reasonable notice and public hearing. Since the revision strengthens 

the SIP, results in new DFW area VOC emission reductions, implements serious area RACT 

requirements for the DFW area and continues RACT controls for the HGB area, approval will not 

interfere with any applicable requirement of the CAA.
Recommendation

It is recommended that the revision to the Texas SIP be approved because:

• It improves the rules that were previously approved

• Results in additional VOC reductions in DFW area

• Ensures that RACT is met for storage tanks with flash emissions in the DFW area and continues 

to be met in the HGB area

• Approval would not interfere with any applicable requirement concerning attainment and 

reasonable further progress or any other applicable requirement of the CAA

Appendices

Appendix A – Excerpt from December 23, 2011 Texas Register

Appendix B – 30 TAC 115, Subchapter B, Division 1 (Storage of Volatile Organic Compounds)