U.S. CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD 

INVESTIGATION REPORT 

REPORT NO. 2009-03-I-VA 

MAY 2009

ALLIED TERMINALS, INC.– CATASTROPHIC TANK 

COLLAPSE

(Two Serious Injuries, Community Evacuation) 

Photo courtesy of City of Chesapeake Fire Marshal 

ALLIED TERMINALS, INC. 

CHESAPEAKE, VIRGINIA

KEY ISSUES: NOVEMBER 12, 2008 

 LIQUID FERTILIZER STORAGE TANK STANDARDS

 TANK MODIFICATION FOR CHANGE-IN-SERVICE 

 TANK INSPECTION 
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Contents 

EXECUTIVE SUMMARY.......................................................................................................................... 1

1.0 INTRODUCTION........................................................................................................................... 3

1.1 Background ..................................................................................................................................... 3

1.2 Investigative Process ....................................................................................................................... 5

1.3 Liquid Fertilizer............................................................................................................................... 5

1.4 Allied Terminals, Inc....................................................................................................................... 6

1.5 HMT Inspection, Inc. ...................................................................................................................... 7

1.6 G&T Fabricators, Inc. ..................................................................................................................... 7

1.7 Aboveground Storage Tank Standards............................................................................................ 7

1.7.1 American Petroleum Institute............................................................................................. 7

1.7.2 The Fertilizer Institute........................................................................................................ 8

1.8 The Elizabeth River......................................................................................................................... 9

2.0 INCIDENT DESCRIPTION ......................................................................................................... 11

2.1 Events Preceding the November 12, 2008 Incident ...................................................................... 11

2.2 The Incident................................................................................................................................... 12

2.3 Post-Incident.................................................................................................................................. 15

2.3.1 CSB Urgent Recommendations........................................................................................ 15

2.3.2 Tank 209........................................................................................................................... 16

2.3.3 Engineering Evaluation .................................................................................................... 17

3.0 INCIDENT ANALYSIS ............................................................................................................... 18

3.1 Tank 201........................................................................................................................................ 18

3.2 Tank Modification......................................................................................................................... 19

3.3 Tank Inspection ............................................................................................................................. 21
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3.4 Tank 201 Failure ........................................................................................................................... 23

3.5 Allied Safe Work Practices ........................................................................................................... 24

3.6 Analysis Summary ........................................................................................................................ 25

4.0 REGULATORY ANALYSIS ....................................................................................................... 26

4.1 Environmental Protection Agency ................................................................................................ 26

4.2 Virginia Department of Environmental Quality............................................................................ 27

4.3 State Aboveground Storage Tank Regulations.............................................................................. 27

5.0 SIMILAR INCIDENTS ................................................................................................................ 28

6.0 FINDINGS .................................................................................................................................... 29

7.0 CAUSES........................................................................................................................................ 30

8.0 RECOMMENDATIONS .............................................................................................................. 31

United States Environmental Protection Agency. ...................................................................................... 31

Governor and Legislature of the Commonwealth of Virginia.................................................................... 31

Allied Terminals, Inc.................................................................................................................................. 32

HMT Inspection, Inc. ................................................................................................................................. 32

The Fertilizer Institute ................................................................................................................................ 33

REFERENCES........................................................................................................................................... 35

APPENDIX A EVENT TIMELINE........................................................................................................... 36

APPENDIX B TANK 209 ENGINEERING EVALUATION................................................................... 38

APPENDIX C RUPTURE HAZARD FROM LIQUID STORAGE TANKS ........................................... 40

APPENDIX D STATE REGULATIONS FOR ABOVEGROUND FERTILIZER STORAGE TANKS. 45

APPENDIX E SIMILAR INCIDENTS ..................................................................................................... 48
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List of Figures 

Figure 1. Allied collapsed tank and neighboring business...........................................................................3

Figure 2. Location of South Hill neighborhood...........................................................................................4

Figure 3. Allied's Chesapeake terminal.........................................................................................................6

Figure 4. Tank 201......................................................................................................................................13

Figure 5. Location of injuries......................................................................................................................14

Figure 6. Tank 209......................................................................................................................................16

Figure 7. Tank 201 design prior to modification. .......................................................................................18

Figure 8. Tank 201 modification design. ....................................................................................................20

Figure 9. Modified Tank 201. .....................................................................................................................21

Figure 10. Failed tank weld on course three. ..............................................................................................24

List of Tables 

Table 1. Calculated maximum liquid levels................................................................................................23
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List of Acronyms and Abbreviations 

API American Petroleum Institute 

ASME American Society of Mechanical Engineers 

AST Aboveground Storage Tank 

CEPPO Chemical Emergency Preparedness and Prevention Office 

CFR Code of Federal Regulations 

CSB U.S. Chemical Safety and Hazard Investigation Board 

CWA Clean Water Act 

DEQ Virginia Department of Environmental Quality 

DOLI Virginia Department of Labor and Industry 

EPA U.S. Environmental Protection Agency 

LOP Lack of Penetration 

OPA 90 Oil Pollution Act of 1990 

TFI The Fertilizer Institute 

UAN 32 Urea Ammonium Nitrate Solution with 32 Percent Nitrogen 

 
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Executive Summary 

On November 12, 2008, a 2-million-gallon liquid fertilizer tank (designated as Tank 201 by the owner) 

catastrophically failed at the Allied Terminals, Inc. (Allied) facility in Chesapeake, Virginia, seriously 

injuring two workers and partially flooding an adjacent residential neighborhood. 

On the day of the incident, Allied was filling Tank 201 with liquid fertilizer to check for leaks prior to 

painting the tank. During the filling, a welder and his helper sealed leaking rivets on the tank. 

At a fill level about 3.5 inches below the calculated maximum liquid level, the tank split apart vertically, 

beginning at a defective weld located midway up the tank. Within seconds, the liquid fertilizer 

overtopped the secondary containment, partially flooding the site and adjacent neighborhood. The 

collapsing tank wall injured the welder and his helper, who were working on the tank. Employees of a 

neighboring business responded and extricated them. At least 200,000 gallons of the liquid fertilizer were 

not recovered; some entered the southern branch of the Elizabeth River. 

The CSB identified the following causes: 

1. Allied did not ensure that welds on the plates to replace the vertical riveted joints met generally 

accepted industry quality standards for tank fabrication. 

2. Allied had not performed post-welding inspection (spot radiography) required for the calculated 

maximum liquid level for the tank. 

3. Allied had no safety procedures or policies for work on or around tanks that were being filled for the 

first time following major modifications and directed contractors to seal leaking rivets while Tank 

201 was being filled to the calculated maximum liquid level for the first time. 
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The CSB makes recommendations to the U.S. Environmental Protection Agency, the Governor and 

Legislature of the Commonwealth of Virginia, Allied Terminals, Inc., HMT Inspection, Inc., and The 

Fertilizer Institute. 
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1.0 Introduction 

1.1 Background 

On November 12, 2008, at about 2:20 pm, a 2-million-gallon nominal capacity liquid fertilizer tank 

catastrophically failed at the Allied Terminals, Inc. (Allied) facility in Chesapeake, Virginia (Figure 1). 

The tank split open vertically and nearly instantaneously released about 2.1 million gallons of liquid 

fertilizer. A welder and his helper were working on the opposite side of the tank as it collapsed. Both 

sustained serious injuries due to the collapsing tank and immersion in the liquid fertilizer. Employees 

from a neighboring business (shown in upper left of Figure 1) rescued the two workers. 

Photo courtesy of City of Chesapeake Fire Marshal

Figure 1. Allied collapsed tank and neighboring business. 
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As the liquid fertilizer released, it overtopped the secondary containment berm1

 surrounding the tank. 

The product flooded Rosemont Avenue, blocking egress for more than 100 employees at the adjacent 

business. It reached portions of the South Hill neighborhood, an adjacent residential community of 43 

homes bordered on two sides by Allied’s property (Figure 2). The City of Chesapeake Fire Department 

ordered residents to evacuate for several days. Weeks later, residents again had to leave their homes 

while an environmental cleanup firm repaired the damage to their property. 

Photo courtesy of City of Chesapeake Fire Marshal

 Figure 2. Location of South Hill neighborhood. 

 

1

 Secondary containment for large storage tanks is usually an earthen berm surrounding the tank which has the 

capacity to contain the tank’s contents if released slowly. 
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At the time of the incident, Allied was filling Tank 201, a liquid fertilizer storage tank, to its calculated 

“safe fill height”2

 of 27.01 feet. During the filling, the welder was to check for and repair leaking rivets. 

However, before the liquid reached the “safe fill height,” a vertical weld seam failed and the tank 

ruptured. 

The City of Chesapeake Fire Department and U.S. Environmental Protection Agency (EPA) On-Scene 

Coordinators managed the spill. Later, teams from the U. S. Chemical Safety Board (CSB), the City of 

Chesapeake Fire Marshal’s Office, the Virginia Department of Labor, the EPA Oil and Prevention 

Branch, and the Virginia Department of Environmental Quality investigated. 

1.2 Investigative Process 

The CSB examined the collapsed tank in situ, photographed the incident site, interviewed eyewitnesses 

and responders, and made physical measurements of the failed tank. The CSB entered into a site control 

and evidence preservation agreement with Allied and the City of Chesapeake. The investigation team 

conducted additional interviews with Allied management, contractors, and tank inspection firms. In 

addition, the CSB met with organizations involved in the commercial fertilizer and liquid terminal 

industries, researched similar fertilizer tank incidents, and examined federal, Commonwealth of Virginia, 

and other state regulatory programs. 

1.3 Liquid Fertilizer 

The liquid fertilizer stored at Allied is a urea ammonium nitrate solution containing 32 percent total 

nitrogen (UAN 32). It is a non-flammable, stable aqueous salt solution. UAN 32 is a heavy, mildly 

 

2

 “Safe fill height,” a term used by Allied, corresponds to the maximum liquid level as determined in API Standards 

650 and 653. 
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corrosive, clear liquid with an ammonia odor and a density of about 11 pounds per gallon.3

 The EPA 

does not regulate UAN 32 fertilizer as a listed chemical. 

1.4 Allied Terminals, Inc. 

Allied Terminals, Inc., a subsidiary of Allied Marine Industries, Inc., is a small, privately-owned chemical 

storage company based in Norfolk, Virginia, that operates liquid terminals in Norfolk and Chesapeake, 

Virginia. The Chesapeake marine terminal (Figure 3) is adjacent to the southern branch of the Elizabeth 

River and provides contract storage and distribution of petroleum products and liquid fertilizers, which it 

receives by ship and pipeline and distributes by barge, rail, and truck. The terminal incorporates property 

and tanks purchased from BP Marine Terminals, ConocoPhillips, and Star Enterprises, Inc. between 1994 

and 2000. The property north of Banks Street contained 10 fertilizer storage tanks, including Tank 201. 

Figure 3. Allied's Chesapeake terminal. 

 

3

 UAN has a specific gravity of 1.33, which is about 30 percent higher than the specific gravity of water. 
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1.5 HMT Inspection, Inc. 

HMT Inspection, Inc. (HMT) is a division of HMT, Inc., an international aboveground storage tank 

(AST) service provider based in Houston, Texas. HMT performs tank inspection, non-destructive 

examination, and engineering evaluations in accordance with the requirements of American Petroleum 

Institute (API) Standard 653 (Section 1.7.1). HMT inspectors are certified by API and receive additional 

in-house inspection training. 

1.6 G&T Fabricators, Inc. 

G&T Fabricators, Inc. (G&T) is an independent welding company based in Wilmington, North Carolina. 

In the six and a half years prior to the incident, G&T performed tank modifications, pipe welding, and 

other maintenance work at Allied’s Chesapeake and Norfolk terminals. During this period, G&T had 

three full-time employees and hired temporary employees as needed. The two contractors injured in the 

incident included one full-time and one temporary G&T employee. 

1.7 Aboveground Storage Tank Standards 

Several standards address industry practices for AST design, construction, maintenance, repair, and 

inspection. These standards, frequently codified into federal, state, or local regulations, typically apply to 

new construction or expansions and modifications inside an existing facility. The principal standards and 

organizations that address ASTs are summarized below. 

1.7.1 American Petroleum Institute 

API is a national trade association that includes 400 corporate members representing segments of the oil 

and natural gas industry. For more than 75 years, API has developed petroleum and petrochemical 

equipment and operating standards. API maintains more than 500 standards and recommended practices, 

many of which have been incorporated into state and federal regulations. 
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API Standard 650, Welded Steel Tanks for Oil Storage, dates back to 1961. This consensus standard 

establishes minimum requirements for material, design, fabrication, erection, and testing for vertical, 

cylindrical, aboveground, steel storage tanks for petroleum, petroleum products, and other liquids. 

Although written for the petroleum industry, this standard is widely used for the storage of both 

hazardous and non-hazardous liquids. Several states have incorporated API 650 by reference into their 

regulations for the storage of both hazardous and non-hazardous liquids, including liquid fertilizer 

(Section 4.4). 

API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction, contains standards applicable 

to inspection, repair, alteration, and reconstruction of vertical, cylindrical, aboveground, steel storage 

tanks. Like API 650, API 653 is widely used and has been incorporated by reference into the storage tank 

regulations of several states. 

API Standard 579-1/ASME FFS-1, Fitness-For-Service (2nd ed.), includes procedures to evaluate the 

integrity of a damaged or degraded component and estimate its remaining life. This standard provides 

techniques to evaluate flaws including, but not limited to, general and localized corrosion, weld 

misalignment and shell distortions, and crack-like defects. 

1.7.2 The Fertilizer Institute 

The Fertilizer Institute (TFI), headquartered in Washington, D.C., is a national organization representing 

the fertilizer industry. Two industry groups merged in 1969 to form TFI. TFI’s members include 

producers, transporters, distributors, retailers, and others involved in the fertilizer industry. TFI 

represents member interests regarding legislation and regulation, conducts studies, collects statistics, and 

provides information to members through conferences and newsletters. TFI membership includes 100 

percent of domestic manufacturers, many of the nation’s largest retailers, and several international 

fertilizer manufacturers. 
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TFI issued Aboveground Storage Tanks of Liquid Fertilizer, Recommended Inspection Guidelines in 2001 

in response to several catastrophic tank failures in the late 1990s and 2000 (Section 5). The guideline 

incorporates by reference API 650 and API 653 and includes additional fertilizer-specific requirements. 

Conformance with this guideline is voluntary; no state or federal regulations mandate its use. 

At the time of the incident, four TFI members had contracted with Allied to store liquid fertilizer. Allied 

is not a TFI member. 

1.8 The Elizabeth River 

The Elizabeth River flows through the Cities of Norfolk, Chesapeake, and Portsmouth, Virginia.4 This 

area has a long history of heavy industrialization and pollution of the waters of the river. Many liquid 

storage terminals, including all of the large liquid fertilizer storage tanks in Virginia, are located along the 

Elizabeth River. 

The Elizabeth River Project is an independent non-profit organization that incorporated in 1993 to support 

the restoration of the river’s environmental health. A board of directors, including local business and 

community leaders, university administrators, and present and former government officers, runs the 

Elizabeth River Project. The Elizabeth River Project provides technical support and recognition to 

businesses and industries in its “River Star” program. These businesses work to reduce pollution, create 

or conserve habitats, and recycle or reuse materials. Several terminals in the Elizabeth River watershed 

are River Star sites. Allied Terminals does not participate in the River Star program. 

On September 15, 2008, the Elizabeth River Project launched a long-term initiative to make the river 

fishable and swimmable by 2020. One of the initiative’s action items is to reduce the amount of nitrogen 

 

4

 A portion of the Eastern Branch of the Elizabeth River also flows through the City of Virginia Beach. 
Allied Terminals May 2009 

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fertilizer that enters the river, as it can increase algae growth and deplete the oxygen resources of aquatic 

species. 
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2.0 Incident Description 

2.1 Events Preceding the November 12, 2008 Incident 

Significant events preceding the November 12, 2008, catastrophic tank collapse at Allied include the 

following; Appendix A is an event timeline. 

1. Circa 1929 – A 2-million-gallon riveted petroleum storage tank (now known as Tank 201) was 

constructed at a site at the end of Rosemont Avenue in what is now the City of Chesapeake. 

2. Late 2000 – Allied negotiated the purchase of an idled petroleum terminal, which included Tank 201, 

at the end of Rosemont Avenue. 

3. December 12, 2000 – Allied contracted AEC Engineering, Inc. (AEC)5

 to inspect storage tanks at the 

idled terminal. 

4. January 2001 – AEC inspected Tank 201 and prepared a preliminary report establishing a maximum 

liquid level of “18.583 feet” [sic] for the liquid fertilizer Allied intended to store in the tank. 

5. February 2001 – Allied canceled the AEC contract; AEC did not issue a final tank inspection report 

for Tank 201. 

6. 2001 to 2006 – Allied used Tank 201 for liquid fertilizer storage. Allied provided no documentation 

with respect to the maximum liquid level (“safe fill height”) used during this time. 

 

5

AEC is a national tank engineering and inspection firm with a local office in Richmond, VA. 
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7. October 2006 – Allied contracted G&T to modify Tank 201 by replacing the vertical riveted joints 

with butt-welded joints.6

 This was to increase the strength of the joints, which would permit an 

increase in the maximum liquid level and allow more fertilizer to be stored in Tank 201. 

8. January 3, 2007 – While G&T was modifying Tank 201, HMT performed an API 653 Out-of-Service 

inspection (Section 3.3) of the tank and calculated its “safe fill height” as 25.65 feet.7

9. September 18, 2007 – HMT specified a revised “safe fill height” of 27.01 feet for Tank 201 based on 

an April 2001metallurgical test report provided by Allied. 

10. January 18, 2008 – Allied conducted a tank strength test8

 using liquid fertilizer, filling Tank 201 to a 

final height of 22 feet, 3 and 11/16 inches (22.31 feet). 

11. January 2008 to November 2008 – Tank 201 was in service holding liquid fertilizer. Allied reported 

that the average fill height during this time was about five feet. 

2.2 The Incident 

On Tuesday November 11, 2008, Allied began filling Tank 201 with liquid fertilizer to find and repair 

rivet weeps9

 in preparation for painting the exterior of the tank. On Wednesday, November 12, 2008, at 

about 2:00 pm, while Allied continued filling the tank to a level between 26 and 27 feet, a welder and 

helper from G&T began sealing weeping rivets. The welder was working in a man-lift about 15 feet 

above ground. The helper was on the ground nearby. 

 

6

 A butt-weld joins two pieces of material along their entire thickness. 

7

 Calculations were based on liquid with a specific gravity of 1.33. 

8

 Allied filled the tank with liquid fertilizer product to test the tank. Although Allied referred to the test as a 

“hydrostatic test,” the test performed did not conform to the API requirements for hydrostatic testing. 

9

 A weep is a small leak that forms a wet spot on the tank exterior. 
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At about 2:20 pm, as the tank reached a level of 26.72 feet, a vertical split started midway up the shell and 

rapidly extended to the floor and roof of the tank on the side opposite the workers. As the pressure of the 

liquid fertilizer inside the tank opened the split, the tank shell separated from the bottom and roof (Figure 

4), rapidly releasing the tank’s contents. 

Photo courtesy of City of Chesapeake Fire Marshal

Figure 4. Tank 201. 

The collapsing tank shell impacted the man-lift, seriously injuring the welder in the man-lift basket. The 

tank stairs fell away from the tank and pinned the helper to the ground. Both workers were briefly 

submerged under the liquid fertilizer. Employees from a neighboring business witnessed the accident and 

quickly extricated the workers. Figure 5 is a close-up of the accident scene showing the man-lift and 

stairs. 
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Figure 5. Location of injuries. 

The liquid fertilizer overtopped the secondary containment, damaging a facility maintenance building and 

flooding portions of the facility and the South Hill neighborhood. At least 200,000 gallons10 of the liquid 

fertilizer were unaccounted for following post-accident cleanup; some flowed into the nearby Elizabeth 

River, about 1,000 feet from the tank. 

 

10As estimated by the EPA. 
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2.3 Post-Incident 

Post-incident visual examinations of Tank 201 identified defective welds as the likely immediate cause of 

the tank failure. Post-incident visual examination of Tanks 202, 205, and 209 (all with welded 

modifications similar to Tank 201) revealed numerous welding defects similar to those observed on the 

remnants of the collapsed tank, including undersized welds, porosity, and weld undercut.11 

2.3.1 CSB Urgent Recommendations 

Because the potential for collapse of Tanks 202, 205, and 209 posed an unacceptably high risk of 

substantial property damage or injuries among the general public, the CSB made the following urgent 

safety recommendations to Allied on December 8, 2008. 

 Take immediate action to reduce the risk of a catastrophic failure of Tanks 202, 205, and 209 at 

Allied Terminals Hill Street facility including but not limited to significantly reducing the 

maximum liquid levels (“safe fill height”) based on sound engineering principles. Report the 

actions taken to the City of Chesapeake. 

 Select and retain a qualified, independent tank engineering firm to evaluate Tanks 202, 205, and 

209 and determine their fitness for continued service. The evaluation should be based on 

recognized and generally accepted good engineering practices, such as API 653 - Tank 

Inspection, Repair Alteration, and Reconstruction and API 579 - Fitness for Service. 

 

11 Holes in welds due to gas bubbles are called “porosity.” Insufficient weld material along the edge of a weld is 

called “undercut.” 
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 Within 30 days, provide the report prepared by the independent tank engineering firm to the City 

of Chesapeake, together with a comprehensive action plan and schedule to address any identified 

deficiencies. 

The CSB released these urgent recommendations at a joint press conference with the City of Chesapeake. 

2.3.2 Tank 209 

The City of Chesapeake, through the Fire Marshal’s Office, independently investigated the Allied 

incident. Based on the evidence collected and the concern for the safety of the residents of the South Hill 

neighborhood, the City of Chesapeake found Tank 209 to be an imminent danger, condemned the tank on 

December 22, 2008, and ordered Allied to drain it within 30 days. Allied drained the tank in accordance 

with the City’s order. 

Figure 6. Tank 209. 
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2.3.3 Engineering Evaluation 

In response to the CSB’s urgent recommendations, Allied contracted Thielsch Engineering, Inc. 

(Thielsch) to conduct an evaluation of the vertical weld joints on Tanks 202, 205, and 209. Thielsch 

performed visual and non-destructive inspections12 of the welds. For Tank 209, the inspections indicated 

up to 75 percent lack of penetration (LOP) in the vertical butt-weld joint of the insert plates.13 Based on 

these results, Thielsch calculated the maximum liquid level for the liquid fertilizer in Tank 209 as 10.227 

feet, significantly less than the 32.14-foot maximum liquid level established in September 2007 by HMT. 

Thielsch’s report is included as Appendix B. 

Fitness-for-Service examinations for Tanks 202 and 205 also identified significant LOP in the welds. The 

engineering firm recommended significantly reducing the maximum liquid levels for these tanks as well. 

 

12 The non-destructive examination used an ultrasonic shearwave technique to examine the internal features of the 

welds. 

13 Lack of weld penetration refers to welds that do not penetrate the full thickness of the plates being welded 

(Section 4.5). 
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3.0 Incident Analysis 

3.1 Tank 201 

Tank 201, originally designed and constructed in 1929 for petroleum product storage, was 116 feet in 

diameter and about 30 feet high. The shell was constructed of overlapping riveted plates, each 

approximately 6 feet high and 14 feet long. The plates were joined end to end to form six rings (courses) 

that were stacked to form the tank. A single row of rivets joined the courses horizontally, while three 

vertical rivet rows joined the plate ends on the bottom two courses and two rows joined the plate ends on 

the upper four courses (Figure 7). Overlapping welded plates were used on the bottom and the coneshaped roof. A second tank bottom was added inside the tank prior to Allied’s purchase of the facility. 

Figure 7. Tank 201 design prior to modification. 
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3.2 Tank Modification 

The liquid fertilizer stored in Tank 201 weighed more per unit volume (density) than the petroleum 

products for which the tank was designed (about 11 pounds per gallon for the UAN 32 solution compared 

to 6 pounds per gallon for petroleum products). To increase the usable capacity of the tank, Allied 

contracted G&T to remove 18-inch wide sections of the shell plates containing the vertical riveted joints 

and replace them with butt-welded plates,14 following the requirements of API 653 (Figure 8). Allied 

intended this modification to strengthen the joints and permit a higher maximum liquid level, and 

contracted G&T to perform the same modification on three similar tanks: Tanks 202, 205, and 209. 

Allied did not have the modifications to Tanks 201, 202, 205, and 209 approved by an authorized 

inspector or an engineer experienced in storage tank design as required by API 653. 

API 653 requires welding procedures and welders be qualified by a formal performance test in 

accordance with the ASME Boiler and Pressure Vessel Code Section IX: Welding And Brazing 

Qualifications. API 653 also requires verifying the weldability of steel from existing tanks when the type 

of steel is unknown. The weldability test involves welding samples removed from the tank and subjecting 

them to mechanical strength tests. Neither Allied nor G&T prepared and qualified a weld procedure in 

accordance with these requirements. In addition, while some of the G&T welders were previously 

qualified to weld similar materials, none qualified on Tank 201 material. 

 

14 A butt-welded joint can be as strong as the material it connects, while a riveted joint is generally weaker. 
Allied Terminals May 2009 

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Figure 8. Tank 201 modification design. 

Following the modifications, Allied paid a non-destructive testing company to examine the welds for 

defects using spot radiography.15 However, Allied paid for the examination of only the lower two courses 

of Tanks 202 and 209. The upper courses of Tanks 202 and 209 and the entirety of Tanks 201 and 205 

were not radiographed prior to returning these tanks to service. The radiography performed identified 

multiple weld defects in the lower courses of both 202 and 209.16 

 

15 Radiographic weld inspection uses gamma-ray technology to identify subsurface weld flaws. Spot radiography 

examines a small percentage of the length of each weld; full radiography examines the full length of all welds. 

16 Based on documentary evidence, it is unclear whether all of these defects were repaired. 
Allied Terminals May 2009 

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Photo from HMT inspection report.

Figure 9. Modified Tank 201. 

3.3 Tank Inspection 

Allied contracted with both AEC and HMT to perform API 653 Out-of-Service inspections of Allied’s 

fertilizer storage tanks. An API 653 Out-of-Service inspection typically includes internal and external 

visual inspections for corrosion and degradation; measuring tank roof, floor, and shell thicknesses; and 

calculating a maximum liquid level. Tank inspectors calculate the maximum liquid level based on 

 minimum measured shell thicknesses, 

 material type (from a list of known materials or unknown material), 

 joint design (welded or riveted), and 

 extent of weld inspection (full, spot, or no radiography). 
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AEC inspected the tanks in late 2000 and early 2001 before Allied contracted G&T to replace the vertical 

rivet joints with butt-welded plates. As part of the inspection, AEC determined maximum liquid levels 

for the tanks based on the requirements specified in API 653 for riveted construction of an unknown 

material type17 using the smallest (minimum)18 of 228 thickness measurements taken on the lowest tank 

course.19

HMT performed inspections in 2004 through 2007. As part of this effort, HMT calculated “safe fill 

heights” for Tanks 201, 202, 205, and 209 based on the requirements of API 653 for a spot radiographed 

butt-welded vertical joint of an unknown material type using the average of 10 thickness measurements 

from the lowest course. In September 2007, following the issuance of the inspections reports, HMT 

increased the “safe fill heights” for Tanks 201, 202, and 209 based on a known material type. HMT chose 

this material type based on the test results20 from a single sample from each tank. Table 1 summarizes the 

calculated maximum liquid levels. 

 

17 When the material type is unknown, API requires using lower allowable limits in calculating a maximum liquid 

level. 

18 API 653 paragraph 4.3.3.1 specifically requires using the minimum measured thickness . 

19 For Tank 201, the thickness of the lowest course limited the maximum liquid level. 

20 Chemical composition and mechanical strength tests. 
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Table 1. Calculated maximum liquid levels. 

Tank AEC Engineering 

Pre-modification 

HMT Inspection 

Post-modification 

HMT Inspection 

September 2007 

201 18.70 25.65 27.01 

202 17.00 26.14 27.45 

205 25.92 35.0021 -- 

209 19.25 30.60 32.14 

HMT’s use of test results from a single sample from each tank was not sufficient to establish the material 

type for the entire tank. The only provision in API 653 for establishing the properties of an unknown 

material based on testing is in paragraph 7.3 “Original Materials for Reconstructed Tanks.” 22 This 

paragraph requires sampling and testing each individual plate. In the case of Tank 201 this would have 

been more than 150 samples. Additionally, HMT’s use of the average of only 10 thickness measurements 

resulted in a higher than allowed maximum liquid level for Tank 201. Had HMT used minimum 

measured thickness of the plate (0.485 inches), the HMT-calculated maximum liquid level would have 

been about 1.5 inches less than the level at which the tank failed. 

3.4 Tank 201 Failure 

Welds on the plates to replace the vertical riveted joints failed because the welds (Figure 10) did not meet 

generally accepted industry quality standards for tank fabrication. The welds did not penetrate the full 

thickness of the plates. Furthermore, the welds contained defects—porosity (holes from gas bubbles in 

 

21 Fill height for Tank 205 was limited by the tank’s physical height. 

22 A tank which is disassembled and reconstructed at a new location. 
Allied Terminals May 2009 

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the weld) and undercut (insufficient weld material along the edge of the weld)—that significantly 

degraded the strength of the welds. 

Figure 10. Failed tank weld on course three. 

Had the welds been radiographed as required by API 653, these weld defects would most likely have been 

detected and should have been repaired. 

3.5 Allied Safe Work Practices 

Tanks are more likely to fail when being filled to the maximum level for the first time.23 Allied had no 

safety procedures or policies for work on or around tanks following construction or major modifications. 

 

23 API 653 section 5.2.2 discusses tank failure during hydrostatic testing or first fill. 
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Allied directed G&T to seal leaking rivets while Tank 201 was being filled to its calculated “safe fill 

height” for the first time. Both G&T workers were injured when the tank collapsed. 

3.6 Analysis Summary 

Although Allied documents required API 653 be applied for the modification and inspection of Tank 201, 

key requirements were not met, including (but not limited to) 

 Allied did not use an authorized inspector or an engineer experienced in storage tank design to 

approve the modifications to Tank 201. 

 G&T did not use qualified weld procedures or welders to perform the modification in accordance 

with the ASME Boiler and Pressure Vessel Code, Section XI: Welding and Brazing 

Qualification. 

 Allied did not require or perform spot radiography on Tank 201.24

 HMT calculated a maximum liquid level for Tank 201 using the requirements for weld joints that 

are spot radiographed. 

 HMT calculated a maximum liquid level for Tank 201 based on an average wall thickness in lieu 

of a minimum wall thickness. 

Had Allied, G&T, and HMT all followed the requirements of API 653, Tank 201 would not have failed. 

 

24 API 653 states that the owner/operator of a tank has ultimate responsibility to ensure requirements, including 

radiography, are met. 
Allied Terminals May 2009 

26

4.0 Regulatory Analysis 

4.1 Environmental Protection Agency 

The EPA regulates ASTs under the Oil Pollution Act of 1990 (OPA 90). Regulatory programs under this 

act require facilities, including aboveground storage facilities, to develop and implement Spill Prevention, 

Control, and Countermeasure (SPCC) Plans to address potential oil discharges and Facility Response 

Plans (FRP) for worst-case oil discharge scenarios. Allied’s Chesapeake terminal is subject to these 

regulations for its petroleum storage tanks. Storage of other materials, including liquid fertilizer, is not 

covered under OPA 90. 

The Clean Water Act (CWA) regulates discharge of pollutants to waters of the United States including 

surface waters such as the Elizabeth River. Although the CWA does not specifically address ASTs, any

unpermitted release to waterways—even an accidental release such as the incident at Allied—is subject to 

CWA enforcement. However, the CWA does not mandate steps to take to prevent such releases. 

No EPA program specifically regulates non-petroleum service ASTs. Individual states are responsible for 

any non-petroleum AST regulation. However, following a series of catastrophic liquid fertilizer tank 

failures between 1997 and 2000 (Section 5), EPA’s Chemical Emergency Preparedness and Prevention 

Office (CEPPO) issued a Rupture Hazard from Liquid Storage Tanks Chemical Safety Alert (Appendix 

C). The alert summarized tank failures due to defective welding, cautioned owners of ASTs in all liquid 

services to be aware of rupture risks, and provided guidance for proper AST inspection and maintenance. 

To minimize risk, it recommended the use of API Standards 650, 653, and 579 for tank construction, 

inspection, and modification, respectively. 
Allied Terminals May 2009 

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4.2 Virginia Department of Environmental Quality 

The Virginia Department of Environmental Quality (DEQ) regulates petroleum ASTs under Virginia’s 

“Facility and Aboveground Storage Tank Regulations.” Neither the Commonwealth of Virginia nor the 

City of Chesapeake regulates non-petroleum ASTs.25

4.3 State Aboveground Storage Tank Regulations 

The CSB identified 17 states that have regulatory programs applicable to storage of liquid fertilizer in 

ASTs (Appendix D). All of these have some requirement for secondary containment, and most also 

include inspection, recordkeeping, and facility permitting or registration requirements. Thirteen state 

programs are specific to fertilizer; four states enforce more general AST regulations that may include 

fertilizer tanks. Seven state programs incorporate API 650 or 653 standards for tank construction, 

inspection, and repair. 

 

25 Under Virginia law, local jurisdictions generally may not exercise authorities not specifically granted to them by 

the state. The Commonwealth of Virginia has not granted such authority with regard to regulation of ASTs. 
Allied Terminals May 2009 

28

5.0 Similar Incidents 

In addition to the incident at Allied, the CSB found 16 other tank failures at nine facilities in other states 

between 1995 and 2008. These 16 failures resulted in one death, four hospitalizations, one community 

evacuation, and two releases to waterways (Appendix E). Eleven occurred due to defective welding. 

In 1989, a large fertilizer tank, similar to the one at Allied, collapsed at a terminal in Chesapeake, 

Virginia. The tank released hundreds of thousands of gallons of UAN solution into the southern branch 

of the Elizabeth River. 
Allied Terminals May 2009 

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6.0 Findings 

1. Although The Fertilizer Institute issued recommended inspection guidelines for liquid fertilizer tanks 

in 2001, incorporating API 653 by reference, Allied was unaware of these guidelines prior to the 

incident. 

2. HMT calculated a “safe fill height” for Tank 201 using the requirements for weld joints that are spot 

radiographed. Allied did not ensure spot radiography was performed on Tank 201. 

3. Tank 201 failed at a liquid level of about 26.74 feet, which was less than the calculated “safe fill 

height” of 27.01 feet. 

4. Allied had no safety procedures or policies for work on or around tanks that were being filled for the 

first time following construction, reconstruction, or major modification. The collapse of Tank 201 

seriously injured the two contractors working on the tank. 

5. The liquid fertilizer overtopped the secondary containment, flooding portions of the facility and an 

adjacent residential neighborhood. Liquid fertilizer also spilled into the nearby Elizabeth River. 

6. Post-incident visual examination of Tank 201 identified defective welds as the likely immediate cause 

of the tank failure. 
Allied Terminals May 2009 

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7.0 Causes 

1. Allied did not ensure that welds on the plates to replace the vertical riveted joints met generally 

accepted industry quality standards for tank fabrication. 

2. Allied had not performed post-welding inspection (spot radiography) required for the calculated 

maximum liquid level for the tank. 

3. Allied had no safety procedures or policies for work on or around tanks that were being filled for the 

first time following major modifications and directed contractors to seal leaking rivets while Tank 

201 was being filled to the calculated maximum liquid level for the first time. 
Allied Terminals May 2009 

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8.0 Recommendations 

United States Environmental Protection Agency. 

2009-03-I-VA-R4 

Revise and reissue the Chemical Emergency Preparedness and Prevention Office Rupture Hazard from 

Liquid Storage Tanks Chemical Safety Alert. At a minimum, revise the alert to 

 Include the Allied Terminals tank failure, 

 Discuss the increased rupture hazard during first fill or hydrostatic testing, and 

 List The Fertilizer Institute fertilizer tank inspection guidelines in the reference section. 

Governor and Legislature of the Commonwealth of Virginia 

2009-03-I-VA-R5 

Require state regulation of 100,000-gallon and larger fertilizer storage tanks (which presently are located 

solely along and in the area of the Elizabeth River) or authorize local jurisdictions to regulate these tanks. 

The regulations should 

 Address design, construction, maintenance, and inspection of 100,000-gallon and larger liquid 

fertilizer storage tanks, and 

 Incorporate generally recognized and accepted good engineering practice. 
Allied Terminals May 2009 

32

Allied Terminals, Inc. 

2009-03-I-VA-R6 

Hire a qualified independent reviewer to verify that maximum liquid levels for all tanks at Allied’s 

Norfolk and Chesapeake terminals meet the requirements of American Petroleum Institute Standard 653, 

Tank Inspection, Repair, Alteration, and Reconstruction. At a minimum, the review should verify that all 

requirements for welding, inspection of welds, and In-Service and Out-of-Service tank inspections are 

met. Make the complete review report for both terminals available to the Cities of Norfolk, Chesapeake, 

and Portsmouth, Virginia, as well as the Virginia Department of Environmental Quality. 

2009-03-I-VA-R7 

Develop and implement worker safety procedures for initial filling of tanks following major modification 

or change-in-service. At a minimum, require the exclusion of all personnel from secondary containment 

during the initial filling. 

HMT Inspection, Inc. 

2009-03-I-VA-R8 

Implement The Fertilizer Institute’s inspection guidelines as part of tank inspector training and inspection 

procedures for fertilizer tank inspection. 

2009-03-I-VA-R9 

Revise company procedures to require tank inspectors to verify that radiography required as part of the 

calculation for a maximum liquid level has been performed. 
Allied Terminals May 2009 

33

The Fertilizer Institute 

2009-03-I-VA-R10 

Formally recommend to all member companies the incorporation of The Fertilizer Institute tank 

inspection guidelines into contracts for the storage of liquid fertilizer at terminals. 
Allied Terminals May 2009 

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By the 

U.S. Chemical Safety and Hazard Investigation Board 

John S. Bresland 

Chair 

Gary Visscher 

Member 

William Wark 

Member 

William Wright 

Member 

Date of Board Approval 
Allied Terminals May 2009 

35

References 

American Petroleum Institute (API), 2007. Welded Steel Tanks for Oil Storage, API 650, 11th edition. 

American Petroleum Institute (API), 2008. Tank Inspection, Repair, Alteration, and Reconstruction, API 

653, 3rd edition, Addendum 3. 

American Society of Mechanical Engineers (ASME), 2004. Boiler and Pressure Vessel Code, Section 

IX: Welding and Brazing Qualifications. 

Atherton, W., no date. Catastrophic Failure of Storage Tanks and Secondary Containment, Liverpool 

Moors University, School of the Build Environment. Accessed 13 February 2009 via 

http://www.ljmu.ac.uk/BLT/BUE_Docs/atherton.pdf 

Chemical Emergency Preparedness and Prevention Office (CEPPO), 2001. Rupture Hazard from Liquid 

Storage Tanks, United States Environmental Protection Agency (EPA). 

Cornell, J.R., and Baker, M.A., 2002. Catastrophic Tank Failures: Highlights of Past Failures along 

with Proactive Tank Designs, Paper presentation at U.S. EPA Fourth Biennial Freshwater Spills 

Symposium, March 19-21, 2002. 

Myers, P. E., 1997. Aboveground Storage Tanks, McGraw-Hill. 
Allied Terminals May 2009 

36

Appendix A 

Event Timeline 
Allied Terminals 

12/5/2000

Allied finalizes purchase of

 Star Enterprises terminal

11/22/2000

AEC Engineering 

submits proposal 

for inspection of tanks in 

Star Enterprises terminal 

12/12/2000

Allied hires AEC 

to inspect tanks

2/2001

Allied halts AEC’s work, 

no final report issued

for Tank 201

1/2001

AEC inspects Tank 201,

 writes preliminary report, 

fill height of 18.583'

1/18/08

Allied completes strength test of 

Tank 201, fill height 22' 3 11/16"

1/3/2007

HMT inspects Tank 201, issues 

safe fill height of 25.65'

10/2006-1/2007

G & T Fabricators alters Tank 201, replacing 

rivets with welds; hires additional welders 

from staffing agency

2001-2006

Allied stores liquid 

fertilizer in riveted Tank 201

9/18/2007

HMT sends email listing

 “revised safe fill height” 

for Tank 201 of 27.01'

Allied b

to safe fil

Tank 

2000

Allied seeks to purchase 

Star Enterprises terminal
Allied Terminals May 2009 

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Appendix B 

Tank 209 Engineering Evaluation 

 
Allied Terminals May 2009 

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Note: Vandeventer Black, LLP is the law firm representing Allied. 
Allied Terminals May 2009 

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Appendix C 

Rupture Hazard from Liquid Storage Tanks 
Allied Terminals May 2009 

41
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42
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43
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44
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45

Appendix D 

State Regulations for Aboveground Fertilizer Storage Tanks 
Allied Terminals 

State Program Description 

Secondary 

Containment 

Inspection 

Recordkeeping 

Permitting/ 

Registration 

Incorporates 

API 650 & 653 

Delaware 

Jeffrey Davis Aboveground Storage Tank Act and subsequent regulations apply to tanks converted from petroleum service after 1992, regardless of their current contents Yes Yes Yes Yes Yes 

DeTitlAb

Florida 

Department of Environmental Protection regulates Aboveground Storage Tank Systems containing 

pollutants, including substances that release ammonia when discharged Yes Yes Yes Yes Yes 

Flo762 

Illinois 

Department of Agriculture regulates all agrichemical facilities storing commercial bulk fertilizer Yes Yes Yes Yes No 

8 Il(IA

Indiana 

Indiana State Chemist enforces Indiana Commercial Fertilizer Rules for facilities storing fluid bulk fertilizer in quantities greater than 55 gallons Yes No No Yes No 

355 Co

Iowa 

Agriculture and Land Stewardship Department regulates Containment of Pesticides, Fertilizers, and Soil Conditioners, including storage of fertilizer in volumes greater than 5,000 gallons Yes No No No No 

Iow21-

Kansas 

Department of Agriculture regulates bulk storage of commercial fertilizers in amounts more than 2,000 gallons Yes Yes Yes Yes 

650 only 

KaRe

Kentucky 

Department of Agriculture Division of Pesticide Regulation regulates storage and handling of bulk fertilizer in amounts greater than 5,000 gallons at commercial facilities Yes Yes No Yes No 

302 Ru

Massachusetts 

Office of the State Fire Marshal enforces regulations requiring permitting, recordkeeping, and inspection of all aboveground storage tanks over 10,000 gallons capacity 

Discretion of fire dept. Yes Yes Yes 

Or equal 

502 Re
Allied Terminals 

State Program Description 

Secondary 

Containment 

Inspection 

Recordkeeping 

Permitting/ 

Registration 

Incorporates 

API 650 & 653 

Michigan 

Department of Agriculture regulates on-farm bulk storage of fertilizer of more than 2,500 gallons in one container or more than 7,500 gallons aggregate Yes Yes No No No 

MicR 2

Minnesota 

Minnesota Pollution Control Agency regulates ASTs of greater than 1,100 gallons containing any liquid substance that may cause pollution to waters of the state; incorporates by reference API 653 Yes Yes Yes Yes Yes 

MinCh

Nebraska 

Department of Environmental Quality implements Rules And Regulations Pertaining to Agricultural Chemical Containment for bulk fertilizer storage Yes Yes Yes No No 

NeTitl

Ohio 

Department of Agriculture regulates all farm fertilizer 

tanks of 5,000 gallons or more aggregate capacity Yes Yes Yes No 

653 only 

Oh(OA

Oklahoma 

Oklahoma Fertilizer Act and Rules implemented by the Oklahoma Department of Agriculture, Food, and Forestry regulate facilities storing liquid bulk fertilizer in quantities greater than 55 gallons Yes Yes No Yes No 

Ok(OA

South Dakota 

Department of Agriculture enforces Bulk Commercial Fertilizer Storage Rules for facilities capable of storing more than 300 gallons Yes Yes Yes Yes No 

SoRu

Washington 

Department of Agriculture regulates Fertilizer Bulk Storage and Operational Area Containment for greater than 500 gallons Yes Yes Yes No No 

ChAd

West Virginia 

Department of Agriculture regulates facilities storing 

over 5,000 gallons of liquid fertilizer for more than 30 days per year Yes Yes Yes Yes No 

61 (CS

Wisconsin 

Department of Agriculture, Trade, and Consumer Protection regulates fertilizer bulk storage in 

quantities greater than 55 gallons Yes Yes Yes No Yes 

AgPro
Allied Terminals May 2009 

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Appendix E 

Similar Incidents 
Allied Terminals 

Date Location 

Number of failures Details Cause (if known) 

Conseqreporte

1995 Poneto, Indiana 1 

500,000-gallon fertilizer tank rupture Faulty welds 

March 1997 

Pacific Junction, Iowa 3 

1-million gallon fertilizer tank rupture and cascading failure of two other tanks Faulty welds 

TemporpreventMissour

February 1999 Dixon, California 1 

Tank rupture during transfer out of leaking tank; 250,000 gallons released 

One killhospital

July 1999 Maumee, Ohio 2 

Failure of two fertilizer storage tanks Faulty welds 

July 1999 

Webberville, Michigan 1 

1-millon gallon fertilizer tank rupture at seams Faulty welds Two hos

January 8, 2000 Cincinnati, Ohio 1 

Million-gallon tank rupture, 379,000 gallons released Faulty welds 

Release River, cwalls anvehicles 

January 26, 2000 Morral, Ohio 1 1.5-million gallon tank rupture Faulty welds March 3 and March 8, 2000 Morral, Ohio 2 

Two separate fertilizer tank ruptures days apart Faulty welds 

Commuschool e

November 7, 2008 

Wilmington, North Carolina 1 

Fertilizer tank failure at seam between shell and bottom 

Failure at weld, corrosion Release 

November 12, 2008† Chesapeake, Virginia 1 Catastrophic failure of fertilizer tank 

Faulty welds due to lack of weld penetration 

Commuevacuathospitalto Eliza

December 16, 2008 Ashkym, Illinois 3 

500,000-gallon release due to storage tank catastrophic failure and cascading failure of two smaller tanks 

† Allied Terminals incident included (highlighted) for comparison.