1

MEMORANDUM | 23 January 2009

TO Cho-Yi Kwan and Timothy Roberts, EPA

FROM Cynthia Manson, Todd Chamoy, and Mark Ewen, Industrial Economics, Inc. 

SUBJECT

Detailed Assessment of UST Universe by Tank Use and Industry Sector

(WA 1-25, Task 6)

Under the requirements of the Regulatory Flexibility Act (RFA) of 1980, as amended by 

the Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA) and 

Executive Order (EO) 13272, entitled “Proper Consideration of Small Entities in Agency 

Rulemaking,” agencies must consider the potential impact of regulations on small 

businesses, small governmental jurisdictions, and small organizations during the 

development of their rules. EPA’s Office of Underground Storage Tanks (OUST) is 

currently exploring the possibility of revising existing regulations associated with certain 

types of underground storage tank (UST) systems and equipment. This memorandum

presents estimates of the number of facilities and tanks, and the purposes of those tanks, 

for informing future small business regulatory analyses.

This memo classifies the universe of USTs into the following categories:

Service station tanks;

Airport hydrant systems;

Emergency generator tanks;

Field-constructed tanks;

Non-retail refueling tanks; and

Tanks storing substances other than fuel.

We will also include a discussion of USTs found on Tribal lands, including privatelyowned USTs as well as those owned by Tribal governments.

This section describes the regulated universe of USTs. We first distribute the known 

USTs by type or purpose of tank using two possible methodologies that provide a range 

of values. Next, we examine whether data on the contents of the tanks will help further 

refine these estimates. Finally, we conclude with a discussion of the industries using tanks 

on Tribal lands.

TYPES AND PURPOSES O F USTS

Potential OUST regulatory revisions may affect six general categories of USTs:

INTRODUCTION AND 

BACKGROUND 

THE UST UNIVERSE
2

Tanks storing fuel at retail service (i.e., gas) stations;

Tanks (both storage tanks and hydrants) that are part of stationary airport hydrant 

refueling systems;

Field-constructed tanks;

Tanks storing fuel to provide emergency generator support, including emergency 

tanks at nuclear power plants;

Non-retail tanks storing fuel for fleet owners; and

Tanks storing substances other than fuel (e.g., used oil or hazardous substances).

According to EPA data, approximately 630,000 tanks were in active use or temporarily 

closed at the end of fiscal year 2007, the latest year for which we have data.

1 To distribute 

this total across the six categories we rely primarily on two previous research efforts. In 

the first analysis, IEc, in conjunction with PCCI, estimated the state-level distribution of 

USTs based on data from the Energy Information Administration (EIA), the EPA, and 

other sources.

2

Separately, E2, Incorporated, analyzed state databases to determine the 

national-level distribution of tanks by industry.3 We further refine these analyses to 

include more specific state-level data where available and to distribute non-service station 

tanks among their various uses. 

Exhibit 1 lists our best estimates of tanks distributed by use derived from the original 

PCCI and E2 methodologies. Both of these analyses indicate that motor fuel retailers 

account for the majority of tanks in the United States, although a considerable 

discrepancy exists between the two estimates. We have reliable estimates of the number 

of airport hydrant refueling systems and field constructed tanks from the Federal Aviation 

Administration (FAA) and the Defense Energy Support Center (DESC). However, it 

appears that most, if not all, airport hydrant refueling tanks are aboveground storage 

tanks; therefore, we do not consider these tanks further in this memo.4 We rely on state 

databases to estimate the number of emergency generator tanks and non-fuel tanks, and 

we assume the remaining tanks are non-retail tanks used to provide fuel for fleet vehicles

(e.g., government-owned vehicles, car dealerships, school bus operators).

 

1

EPA, “FY2007 End-of-Year Activity Report,” December 5, 2007, as viewed at http://www.epa.gov/oust/cat/ca_07_34.pdf 

on December 18, 2008.

2

See Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential Revisions to the UST 

Regulations; Tasks 2-4, Work Assignment 1-25,” November 20, 2008, and appendices.

3

See E2, Incorporated, “Delivery Prohibition - Draft Preliminary Analyses,” December 18, 2006.

4

See Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential Revisions to the UST 

Regulations; Tasks 2-4, Work Assignment 1-25,” November 20, 2008, Appendix A, p.9.
3

EXHIBIT 1 DISTRIBUTION OF TANKS BY USE

USE CATEGORY

NUMBER OF TANKS

(MODIFIED PCCI 

METHODOLOGY)

NUMBER OF TANKS

(MODIFIED E2

METHODOLOGY)

Service Station Tanks 430,1441482,3188

Field-Constructed Tanks (FCTs)2239 239

Nuclear Emergency Generator Tanks (EGTs)3104 104

Other Emergency Generator Tanks (EGTs) 18,925418,5389

Other (Non-fuel) Tanks 25,040523,73610

Non-Retail Fleet Refueling Tanks6155,414 104,931

Total Active USTs7629,866 629,866

Notes:

1. Equal to 2.65 times the number of service stations reported by the EIA and other 

sources, adjusted downwards in states where that value would exceed the total number 

of tanks. Also adjusted for more precise state data available in state and Tribal land UST 

databases.

2. Industrial Economics, “Preliminary Assessment and Scoping of Data Related to 

Potential Revisions to the UST Regulations; Tasks 2-4, Work Assignment 1-25,” November 

20, 2008, Appendix A.

3. Industrial Economics, “Preliminary Assessment and Scoping of Data Related to 

Potential Revisions to the UST Regulations; Tasks 2-4, Work Assignment 1-25,” November 

20, 2008, Appendix A.

4. Equal to 3 percent of total tanks, based on weighted average in databases from 

Florida, Massachusetts, Missouri, and Wisconsin, except in several states where there are 

not enough tanks to fill the remaining categories.

5. Equal to 4 percent of total tanks, except in Iowa, where there are not enough 

remaining tanks to fill this category, and Alaska, where the state database identified 59 

tanks containing used oil.

6. Equal to all unaccounted-for tanks after calculating other values.

7. EPA, “FY2007 End-of-Year Activity Report”.

8. Equal to 3.13 times the number of service stations reported by the EIA and other 

sources, adjusted downwards in states where that value would exceed the total number 

of tanks. Also adjusted for more precise state data available in state and Tribal land UST 

databases.

9. Equal to 3 percent of total tanks, based on weighted average in databases from 

Florida, Massachusetts, Missouri, and Wisconsin, except in several states where there are 

not enough tanks to fill the remaining categories.

10. Equal to 4 percent of total tanks, except in several states where there are not 

enough tanks to fill the remaining categories, and Alaska, where the state database 

identified 59 tanks containing used oil.

The major difference between the modified PCCI and modified E2 methodologies shown 

in Exhibit 1 is the assumed number of tanks per service station. The estimated number of 

service station tanks under the PCCI methodology assumes the default number of tanks 

per service station is 2.65, whereas the modified E2 methodology assumes the default 

number of tanks per service station is 3.13. Note that this results in approximately 52,000 

additional tanks assigned to service stations under the modified E2 methodology, most of 

which were assigned to fleet refueling tanks under the modified PCCI methodology. For 

a breakdown of the distribution of tanks by state under each methodology, see Appendix

A.

5

 

 

5 Note that under the modified E2 methodology, two states (Alabama and Nevada) result in no tanks being assigned to either 

the fleet refueling or non-fuel categories. Furthermore, for two additional states (South Carolina and Washington), no tanks 

are assigned to the fleet refueling category.
4

As the results show, a number of differences exist between the figures, and certain 

estimates have considerable uncertainty. We discuss these issues below, including: (1) the 

number of tanks at motor fuel retailers; (2) the number of non-retail fleet-refueling tanks; 

(3) the number of emergency generator tanks; and (4) other non-fuel tanks.

Tanks at Motor Fuel Retailers

The number of tanks at motor fuel retailers is an estimate with considerable uncertainty. 

According to EPA’s June 2000 “Report to Congress on a Compliance Plan for the 

Underground Storage Tank Program,” facilities with tanks have an average of 2.65 tanks 

per facility.

6 However, a more recent investigation of state databases by E2

shows an 

average of 2.87 tanks per facility, with retail gas stations specifically having 3.13 tanks 

per facility.

7

Finally, a comparison of the state data in EPA’s “FY2007 End-of-Year 

Activity Report” and data on the number of service stations in each state from the Energy 

Information Administration (EIA) shows that in many states there must be less than 2.65 

tanks per service station, as the total number of active USTs in all sectors is less than 2.65 

times the number of service stations.8

The estimated number of gas stations under the E

2

analysis accounted for 526,000 tanks 

in 2006, which we can adjust downward to approximately 514,000 tanks to account for 

service stations closing in 2007. Using the EPA average of 2.65 tanks per facility (except 

in states where the number of tanks per facility is obviously lower, as discussed above), 

however, IEc and PCCI derived an estimate of 427,500 tanks at service stations. (A 

detailed derivation of this estimate is described in a prior memorandum.9) The actual 

figure is likely somewhere in between. In Exhibit 1, we further refine the estimates with

more precise data from states that publish their UST databases. In addition, we apply the 

E

2

estimated average of 3.13 tanks per service station on a state-by-state basis, adjusting 

downward in states where the total number of tanks is less than 3.13 times the number of 

service stations. As a result, we estimate that the number of tanks at motor fuel retailers 

range approximately between 430,100 and 482,300.

Non-Retail Fleet Refueling Tanks

Further evidence on the distribution of non-service station tanks comes from the Steel 

Tank Institute, who, in 2000, estimated that fleets accounted for just four percent of new 

UST installations.10 However, they further estimate that “institutions” (e.g., universities 

and hospitals) account for six percent of installations, and government account for 

another six percent. These sectors likely include a mix of refueling stations for vehicles 

and emergency generator tanks. In general, the Steel Tank Institute observes that, due to 

EPA regulations and clean-up costs associated with UST leaks, non-retail service station 

 

6

EPA, “Report to Congress on a Compliance Plan for the Underground Storage Tank Program,” June 2000, as viewed at 

http://www.epa.gov/OUST/pubs/rtc_0600.pdf on December 18, 2008, p.38.

7

E

2

, Incorporated, “Delivery Prohibition - Draft Preliminary Analyses,” December 18, 2006.

8

Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential Revisions to the UST Regulations; 

Tasks 2-4, Work Assignment 1-25,” November 10, 2008, Appendix A.

9

Basically, the number of service stations is derived from EIA data and other sources for non-state territories. This value is 

multiplied by 2.65 and compared to the total number of tanks reported in EPA’s “FY2007 End-of-Year Activity Report.” If the 

multiplication results in too many tanks, the rate is adjusted down to either 2.0 or 1.0 such that service stations no longer 

account for more than the total. See Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential 

Revisions to the UST Regulations; Tasks 2-4, Work Assignment 1-25,” November 20, 2008, Appendix A.

10 Geyer, Wayne, “UST History,” 2000, as viewed at 

https://www.steeltank.com/LinkClick.aspx?fileticket=GLBrj44tMj0%3D&tabid=108&mid=502 on November 23, 2008, p. 12.

Note the Steel Tank Institute does not define or otherwise specify what types of businesses are included in the category 

“fleet” in their statistics.
5

facilities that need tanks favor aboveground storage tanks.11 Because we do not have 

reliable estimates of non-retail fleet refueling tanks, and because we believe these tanks 

account for the vast majority of tanks not otherwise specified in this analysis, we assign 

all remaining tanks after calculating the other categories to fleet refueling in order for the 

total to match the EPA’s “FY2007 End-of-Year Activity Report”.

Emergency Generator Tanks

Anecdotal evidence from the Hill Company, a large installer of USTs in Texas, suggests

that up to 80 percent of non-retail service station tanks are part of emergency 

generators.12 However, an examination of state databases suggests a much lower estimate. 

In Massachusetts, only two percent (243 of 11,876) of active USTs in the state database 

are designated as emergency generator tanks, although over 18 percent do not have a 

usage designated.13 Wisconsin identifies a similar percentage of tanks as generators (234 

of 12,354, or 1.9 percent), and while the state does not have any unidentified tanks, 

another 6.5 percent of tanks belong to the broad categories “Industrial” and 

“Mercantile/Commercial”.

14 Missouri identifies approximately 2.5 percent (215 of 8,419) 

of active tanks as emergency generators.15 Finally, while Florida’s database does not 

explicitly identify tanks as emergency generator tanks, according to the tank contents 

field, 3.8 percent (1,130 of 29,028) of tanks have the value “Emergency Generator 

Diesel” listed as the fuel.

16 As a result, for the numbers shown in Exhibit 1, up to three 

percent of the total tanks in a state are categorized as emergency generator tanks based on 

the weighted average rate in the four states reporting this distinction. While four states are 

not enough to provide statistical significance in our national estimates, these states 

represent several regions of the United States, have differences in regulation for 

emergency generators, and present a tight range of estimates of emergency generator 

tanks, suggesting that it may be reasonable to assume that these numbers are 

representative of national patterns.

Other Tanks

Exhibit 1 reprints the estimates of field-constructed tanks and emergency generator tanks 

at nuclear power plants from our previous research.17 We believe these estimates are 

derived from reliable sources, but they nonetheless represent a small fraction of tanks, so 

these uses did not merit further investigation. Finally, up to 4 percent of tanks are 

designated as tanks for storage of non-fuel products.18

TANK CONTENTS

To further improve the precision of our estimates above, we investigated the types of 

fuels or other chemicals contained in the state databases. This proved to be less helpful 

than we anticipated due to the dual-use nature of diesel (i.e., diesel is a popular fuel for 

both trucks and emergency generators). Alaska is the only state where tank content data 

compelled us to adjust our results, due to the relatively high number of tanks storing used 

 

11 Geyer, Wayne, “UST History,” 2000, as viewed at 

https://www.steeltank.com/LinkClick.aspx?fileticket=GLBrj44tMj0%3D&tabid=108&mid=502 on November 23, 2008, p. 10.

12 Personal communication with Tommy Dillard, Estimator/Project Coordinator, the Hill Company, on November 24, 2008.

13 Massachusetts’ UST database is available at http://www.mass.gov/Eeops/docs/dfs/osfm/ust/ust.exe

14 Wisconsin’s UST database is available at http://apps.commerce.state.wi.us/ers/ER-EN-TankArchive.zip

15 Missouri’s UST database is available at http://www.dnr.mo.gov/env/hwp/tanks/internet.zip

16 Florida’s UST database delivered by email from E2

via EPA on December 16, 2008.

17 Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential Revisions to the UST Regulations; 

Tasks 2-4, Work Assignment 1-25,” November 20, 2008, Appendix A.

18 E2

, Incorporated, “Delivery Prohibition - Draft Preliminary Analyses,” December 18, 2006.
6

oil. After excluding the 564 tanks positively-identified as gas station tanks in Alaska, we 

distribute the remaining tanks by content, shown in Exhibit 2. Exhibit 2 also presents, for 

comparison purposes, the values for tank use estimated above.

EXHIBIT 2 NON-SERVICE STATION TANKS BY CONTENTS IN ALASKA

TANK CONTENTS TANKS COMMENTS

Diesel 319 Subset of the 524 emergency generator tanks and fleet 

refueling tanks.

Gasoline 188 Subset of the 489 fleet refueling tanks.

Kerosene 8 Used for jet fuel; included in fleet refueling tanks.

Other 7 Unknown.

Used Oil 59 Exceeds 4% of total tanks; Exhibits 1 and 2 adjusted 

accordingly.

Source: Alaska state UST database provided by E2via EPA.

Gasoline accounts for 188 tanks, well below the 489 fleet-refueling tanks identified 

earlier. Diesel tanks could be distributed as either fleet refueling tanks or emergency 

generator tanks such that this does not conflict with our earlier estimates. The used oil 

tanks, however, exceed four percent of tanks in Alaska; therefore, we adjusted our earlier 

estimates to account for this higher number. This is the only case where the tank contents 

reported in the 13 state databases informed our earlier estimates.

USTS ON TRIBAL LANDS

In general, OUST delegates UST activities to state-level environmental agencies. 

However, EPA is the agency responsible for implementing regulations on Tribal lands. 

Therefore, EPA is interested in specifically characterizing USTs located on Tribal lands. 

In addition, Tribal governments are typically small entities, so Tribal government-owned 

businesses must be considered under RFA/SBREFA. This section provides an estimate of 

the number of tanks on Tribal lands and a discussion of the industries and sectors to 

which these tanks belong.

In 2007, OUST produced a report to Congress entitled, “Report to Congress on 

Implementing and Enforcing the Underground Storage Tank Program in Indian Country.”

In the report, they established that 2,658 active tanks existed on Tribal lands at that 

time.19 This estimate differs only slightly from the 2,665 tanks estimated in the “FY2007 

End-of-Year Activity Report”. We assume the difference is due to the specific date of 

estimation. Exhibit 3 lists the number of tanks in each industry sector as reported in the 

database. Note that, like the rest of the United States, the majority of USTs belong to gas 

stations.

 

19 EPA Office of Underground Storage Tanks, “Report to Congress on Implementing and Enforcing the Underground Storage 

Tank Program in Indian Country,” August 2007, p.28.
7

EXHIBIT 3 DISTRIBUTION OF TANKS BY SECTOR ON TRIBAL LANDS

SECTOR NUMBER OF TANKS

Airlines & Aircraft Owners 7

Auto Dealership 6

Commercial 47

Contractor 2

Farm 18

Federal Military 18

Federal Non-Military 54

Gas Station 1,653

Industrial 15

State/Local Government 120

Other/Unknown 129

Petroleum Distributor 9

Private 9

Residential 2

School 14

Truck/Transporter 6

Utilities 3

Total 2,112

Source: Database of USTs on Tribal lands provided by EPA.

Not surprisingly, the distribution of tanks by sector in Exhibit 3 is similar to the types of 

industries that use USTs in the rest of the United States, although there appear to be 

higher levels of government-owned tanks than elsewhere. Two more interesting pieces of 

data extracted from the database are that only 35 tanks are identified as emergency 

generator tanks, and 724 tanks are identified as tribal-owned. 

Of the 35 emergency generator tanks, only 9 are not owned by the Federal government. 

Based on conversations with two EPA regional inspectors representing Regions 8 and 9, 

we do not believe this figure is reliable. We spoke with EPA officials in Region 8 (Lisa 

Luebke) and in Region 9 (Mary Keil) to hear their experiences inspecting tanks at 

businesses on Tribal lands. Ms. Luebke confirmed that the vast majority of tanks on 

Tribal lands in her region were found at gas stations. Ms. Keil was able to provide 

additional detail on industries, as her region includes the Navajo Nation, the largest tribe 

in the United States, which accordingly accounts for the largest number and variety of 

tanks. She listed several applications that are also commonly found outside of Indian 

Country, including bus depots at schools, emergency generators at hospitals, and Tribal 

government fleet refueling sites. In addition, she identified casinos and mining companies 

as firms that she suspects are over-represented on Tribal lands. In her experience, casinos 

all have emergency generator facilities, and many also operate their own retail gas 

stations. While the database identified numerous casino-operated gas stations, it contains

only three casino-owned emergency generator tanks. Unless the remaining casinos use 

aboveground storage tanks, this is a low estimate.
8

Thus, other than the existence of casinos and natural resource extraction industries, we 

are unable to identify any substantial differences between the types of businesses owning 

USTs on Tribal lands and businesses in the rest of the United States. In addition, a large 

number of tanks (approximately one-third) are owned by Tribal governments, most of 

which are small entities.

The number and uses of tanks described in this memo are based on various sources. 

While the total number of active, regulated USTs is relatively precise, we have 

encountered several conflicting estimates of how those USTs are distributed among 

industries and uses. Therefore, we present two estimates of these distributions, with 8.3 

percent of the tanks redistributed between the estimates. However, the actual number of 

tanks of a particular type could be higher or lower than the figures presented in this 

memo.

The data presented in this memo on tanks on Tribal lands have several areas of 

uncertainty as well. Most significantly, three of the EPA regions representing 14 states

and two territories are not included in this analysis.

NEXT STEPS 

This analysis provides a general estimate of the number and type of USTs currently in 

use, and the general distribution of UST use across industrial sectors. While the priorities 

for refining this analysis will be determined in part by the specific regulatory options 

under consideration, the following options may provide useful insights:

Additional data on Tribal ownership patterns: The data collected to date do 

not address all tanks on Tribal lands and rely on limited contacts with EPA 

regional staff. If Tribal ownership or sector distribution of tanks on tribal lands is 

central to EPA’s rulemaking effort, collection of additional data on tank 

ownership and use from remaining regions and Tribes, as well as supplemental 

data from the regions already contacted, could be useful.

Detailed analysis of specific sectors or tank applications: This analysis 

provides general information on the industrial sectors and uses of USTs; if EPA 

determines that a specific sector (e.g., agriculture, health care, or local 

government) requires consideration to address small business impacts or to 

determine more about how tanks are used and distributed among facilities of 

different sizes, then additional sector-specific research to augment the general 

state data may be useful.

Refinement of estimate of retail gasoline establishments and tank use: This 

analysis identifies discrepancies in the number of tanks and establishments 

associated with the retail sale of motor fuel. If EPA determines that the 

uncertainty associated with retail motor fuel tank usage would have a significant 

impact on estimates of total regulatory cost, then refining this set of estimates may 

be useful. At a minimum, updating the estimate to reflect 2007 Economic Census 

data (when available) is potentially useful because it will reflect more recent 

gasoline sales figures and facility ownership patterns.

KEY SOURCES OF 

UNCERTAINTY AND NEXT 

STEPS
9

APPENDIX A

EXHIBIT A-1 DISTRIBUTION OF TANKS BY STATE AND USE (MODIFIED PCCI METHODOLOGY)

STATE OR 

TERRITORY

SERVICE 

STATION 

TANKS1

FCT2 NUCLEAR 

EGT3

OTHER 

EGT4

NON-RETAIL 

FLEET 

REFUELING 

TANKS5

OTHER 

(NON-FUEL) 

TANKS6

TOTAL 

ACTIVE 

USTS7

Alabama 16,430 0 5 567 1,127 756 18,885

Alaska 564 4 0 35 489 59 1,151

American Samoa 11 0 0 1 3 1 16

Arizona 5,300 0 3 211 1,208 281 7,003

Arkansas 7,298 0 2 284 1,492 379 9,455

California 26,421 87 4 1,125 8,362 1,500 37,498

Colorado 5,785 0 0 239 1,607 318 7,949

Connecticut 4,129 0 2 326 5,958 434 10,849

Delaware 1,131 0 0 45 232 59 1,467

District of Columbia 355 0 0 21 292 28 696

Florida 24,552 7 5 866 2,277 1,155 28,862

Georgia 23,120 0 4 902 4,821 1,202 30,049

Guam 111 33 0 9 103 11 267

Hawaii 912 24 0 51 637 68 1,692

Idaho 2,094 0 0 100 976 133 3,302

Illinois 13,250 0 11 678 7,732 903 22,574

Indiana 6,349 0 0 416 6,521 554 13,840

Iowa 7,046 0 1 222 0 103 7,372

Kansas 5,600 0 1 210 877 279 6,967

Kentucky 9,540 0 0 373 2,005 497 12,415

Louisiana 9,673 0 2 379 2,043 505 12,601

Maine 2,746 0 0 96 229 128 3,199

Maryland 5,883 0 2 278 2,710 370 9,243

Massachusetts 7,925 0 1 331 2,323 441 11,021

Michigan 13,208 0 4 605 5,531 807 20,155

Minnesota 9,990 0 3 436 3,521 582 14,532

Mississippi 7,100 0 1 264 1,065 352 8,782

Missouri 8,356 0 1 309 1,190 411 10,267

Montana 1,060 0 0 99 1,999 132 3,290

Nebraska 3,938 0 2 208 2,478 277 6,903

Nevada 3,098 0 0 111 313 147 3,669

New Hampshire 1,700 0 1 92 1,147 123 3,063

New Jersey 8,748 0 4 505 6,899 674 16,830

New Mexico 3,101 0 0 121 644 162 4,027

New York 17,755 0 6 867 9,113 1,156 28,897

North Carolina 18,306 0 5 862 8,383 1,149 28,705

North Dakota 1,844 0 0 65 167 87 2,163
10

STATE OR 

TERRITORY

SERVICE 

STATION 

TANKS1

FCT2 NUCLEAR 

EGT3

OTHER 

EGT4

NON-RETAIL 

FLEET 

REFUELING 

TANKS5

OTHER 

(NON-FUEL) 

TANKS6

TOTAL 

ACTIVE 

USTS7

Northern Mariana 

Islands 48 0 0 3 14 3 68

Ohio 13,078 0 2 690 8,308 920 22,998

Oklahoma 8,613 0 0 334 1,711 445 11,102

Oregon 4,494 0 0 184 1,189 245 6,112

Pennsylvania 12,463 0 9 741 10,476 988 24,677

Puerto Rico 3,146 0 0 137 1,094 183 4,560

Rhode Island 999 0 0 49 513 66 1,627

South Carolina 9,744 5 7 360 1,385 480 11,981

South Dakota 2,790 2 0 91 17 121 3,021

Tennessee 12,104 0 3 514 3,799 685 17,105

Texas 36,464 4 4 1,649 14,627 2,198 54,946

US Virgin Islands 98 0 0 5 35 6 144

Utah 2,981 0 0 121 761 161 4,024

Vermont 1,712 0 1 93 1,138 123 3,067

Virginia 15,189 23 4 618 3,942 824 20,600

Washington 8,098 50 1 304 1,254 405 10,112

West Virginia 3,445 0 0 171 1,852 228 5,696

Wisconsin 10,641 0 3 412 2,120 549 13,725

Wyoming 1,518 0 0 60 322 80 1,980

Tribal Lands 2,086 0 0 80 392 107 2,665

Totals 430,144 239 104 18,925 155,414 25,040 629,866

1. Equal to 2.65 times the number of service stations reported by the EIA and other sources, adjusted 

downwards in states where that value would exceed the total number of tanks. Also adjusted for more 

precise state data available in state and Tribal land UST databases.

2. Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential Revisions to the 

UST Regulations; Tasks 2-4, Work Assignment 1-25,” November 20, 2008, Appendix A.

3. Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential Revisions to the 

UST Regulations; Tasks 2-4, Work Assignment 1-25,” November 20, 2008, Appendix A.

4. Equal to 3 percent of total tanks, based on weighted average in databases from Florida, Massachusetts, 

Missouri, and Wisconsin.

5. Equal to all unaccounted-for tanks after calculating other values.

6. Equal to 4 percent of total tanks, except in Iowa, where there are not enough remaining tanks to fill this 

category, and Alaska, where the state database identified 59 tanks containing used oil.

7. EPA, “FY2007 End-of-Year Activity Report”.
11

EXHIBIT A-2 DISTRIBUTION OF TANKS BY STATE AND USE (MODIFIED E

2 METHODOLOGY)

STATE OR 

TERRITORY

SERVICE 

STATION 

TANKS1

FCT2 NUCLEAR 

EGT3

OTHER 

EGT4

NON-RETAIL 

FLEET 

REFUELING 

TANKS5

OTHER 

(NON-FUEL) 

TANKS6

TOTAL 

ACTIVE 

USTS7

Alabama 18,600 0 5 280 0 0 18,885

Alaska 564 4 0 35 489 59 1,151

American Samoa 13 0 0 1 1 1 16

Arizona 6,260 0 3 211 248 281 7,003

Arkansas 8,620 0 2 284 170 379 9,455

California 31,206 87 4 1,125 3,576 1,500 37,498

Colorado 6,833 0 0 239 559 318 7,949

Connecticut 4,877 0 2 326 5,210 434 10,849

Delaware 1,131 0 0 45 232 59 1,467

District of Columbia 419 0 0 21 228 28 696

Florida 24,552 7 5 866 2,277 1,155 28,862

Georgia 23,120 0 4 902 4,821 1,202 30,049

Guam 131 33 0 9 83 11 267

Hawaii 1,077 24 0 51 472 68 1,692

Idaho 2,473 0 0 100 596 133 3,302

Illinois 15,650 0 11 678 5,332 903 22,574

Indiana 7,499 0 0 416 5,371 554 13,840

Iowa 5,318 0 1 222 1,536 295 7,372

Kansas 5,600 0 1 210 877 279 6,967

Kentucky 11,268 0 0 373 277 497 12,415

Louisiana 11,425 0 2 379 291 505 12,601

Maine 2,746 0 0 96 229 128 3,199

Maryland 5,883 0 2 278 2,710 370 9,243

Massachusetts 7,925 0 1 331 2,323 441 11,021

Michigan 15,600 0 4 605 3,139 807 20,155

Minnesota 9,990 0 3 436 3,521 582 14,532

Mississippi 7,100 0 1 264 1,065 352 8,782

Missouri 8,356 0 1 309 1,190 411 10,267

Montana 1,252 0 0 99 1,807 132 3,290

Nebraska 4,651 0 2 208 1,765 277 6,903

Nevada 3,658 0 0 11 0 0 3,669

New Hampshire 1,700 0 1 92 1,147 123 3,063

New Jersey 10,332 0 4 505 5,315 674 16,830

New Mexico 3,662 0 0 121 82 162 4,027

New York 20,971 0 6 867 5,897 1,156 28,897

North Carolina 21,622 0 5 862 5,067 1,149 28,705

North Dakota 1,844 0 0 65 167 87 2,163
12

STATE OR 

TERRITORY

SERVICE 

STATION 

TANKS1

FCT2 NUCLEAR 

EGT3

OTHER 

EGT4

NON-RETAIL 

FLEET 

REFUELING 

TANKS5

OTHER 

(NON-FUEL) 

TANKS6

TOTAL 

ACTIVE 

USTS7

Northern Mariana 

Islands 56 0 0 3 6 3 68

Ohio 15,447 0 2 690 5,939 920 22,998

Oklahoma 10,173 0 0 334 151 445 11,102

Oregon 5,308 0 0 184 375 245 6,112

Pennsylvania 14,720 0 9 741 8,219 988 24,677

Puerto Rico 3,715 0 0 137 525 183 4,560

Rhode Island 1,180 0 0 49 332 66 1,627

South Carolina 11,509 5 7 360 0 100 11,981

South Dakota 2,106 2 0 91 701 121 3,021

Tennessee 12,104 0 3 514 3,799 685 17,105

Texas 43,069 4 4 1,649 8,022 2,198 54,946

US Virgin Islands 116 0 0 5 17 6 144

Utah 3,521 0 0 121 221 161 4,024

Vermont 2,022 0 1 93 828 123 3,067

Virginia 15,189 23 4 618 3,942 824 20,600

Washington 9,565 50 1 304 0 192 10,112

West Virginia 4,069 0 0 171 1,228 228 5,696

Wisconsin 10,641 0 3 412 2,120 549 13,725

Wyoming 1,793 0 0 60 47 80 1,980

Tribal Lands 2,086 0 0 80 392 107 2,665

Totals 482,318 239 104 18,538 104,931 23,736 629,866

1. Equal to 3.13 times the number of service stations reported by the EIA and other sources, adjusted 

downwards in states where that value would exceed the total number of tanks. Also adjusted for more 

precise state data available in state and Tribal land UST databases.

2. Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential Revisions to the 

UST Regulations; Tasks 2-4, Work Assignment 1-25,” November 20, 2008, Appendix A.

3. Industrial Economics, “Preliminary Assessment and Scoping of Data Related to Potential Revisions to the 

UST Regulations; Tasks 2-4, Work Assignment 1-25,” November 20, 2008, Appendix A.

4. Equal to 3 percent of total tanks, based on weighted average in databases from Florida, Massachusetts, 

Missouri, and Wisconsin, except in several states where there are not enough tanks to fill the remaining 

categories.

5. Equal to all unaccounted-for tanks after calculating other values.

6. Equal to 4 percent of total tanks, except in several states where there are not enough tanks to fill the 

remaining categories, and Alaska, where the state database identified 59 tanks containing used oil.

7. EPA, “FY2007 End-of-Year Activity Report”.