U.S. CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD

INVESTIGATION REPORT 

REPORT NO. 2002-04-I-MO 

MAY 2003

CHLORINE RELEASE

 (66 Sought Medical Evaluation) 

DPC ENTERPRISES, L.P. 

FESTUS, MISSOURI

AUGUST 14, 2002

KEY ISSUES: 

• MECHANICAL INTEGRITY

• EMERGENCY MANAGEMENT

• CHLORINE TRANSFER HOSE SUPPLY
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Contents 

EXECUTIVE SUMMARY ........................................................................................................................11

1.0 INTRODUCTION .........................................................................................................................13

1.1 Background....................................................................................................................................13

1.2 Investigative Process......................................................................................................................15

1.3 Characteristics, Use, and Hazards of Chlorine ..............................................................................15

1.3.1 Characteristics...................................................................................................................15

1.3.2 Products and Safe Handling..............................................................................................16

1.3.3 Health Hazards..................................................................................................................17

1.4 DPC Enterprises Festus Facility ....................................................................................................18

1.5 Surrounding Community ...............................................................................................................20

2.0 CHLORINE REPACKAGING PROCESS ...................................................................................23

2.1 Process Overview...........................................................................................................................23

2.2 Chlorine Tank Cars........................................................................................................................23

2.3 Chlorine Transfer Hose..................................................................................................................25

2.4 Emergency Shutdown System .......................................................................................................25

3.0 DESCRIPTION OF INCIDENT....................................................................................................29

3.1 Pre-Incident Events........................................................................................................................29

3.1.1 Operations at Tank Car Station #3....................................................................................29

3.1.2 Repackaging System Standby and Shutdown Modes.......................................................29

3.2 The Incident ...................................................................................................................................29

3.2.1 The Release.......................................................................................................................29

3.2.2 ESD Valve Failure............................................................................................................31
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3.2.3 Tank Car Excess Flow Valve............................................................................................31

3.2.4 Access to Emergency Response Equipment .....................................................................32

3.2.5 Facility Evacuation ...........................................................................................................32

3.2.6 Community Notification ...................................................................................................32

3.2.7 Emergency Response........................................................................................................34

3.2.8 Cleanup Activities.............................................................................................................36

4.0 RECONSTRUCTIVE ANALYSIS ...............................................................................................38

4.1 Hose Construction..........................................................................................................................38

4.2 Hose Rupture .................................................................................................................................39

4.3 Metallurgical Examination.............................................................................................................40

4.4 ESD Valve Positioning ..................................................................................................................41

4.5 ESD System Testing ......................................................................................................................43

4.6 Excess Flow Valve.........................................................................................................................44

5.0 ANALYSIS OF INCIDENT..........................................................................................................46

5.1 Hose Failure...................................................................................................................................46

5.1.1 Hose Supply Chain ...........................................................................................................46

5.1.2 Hose Identification............................................................................................................47

5.1.3 Opportunities for Error in Supply Chain ..........................................................................47

5.1.4 Positive Materials Identification.......................................................................................49

5.2 Mechanical Integrity ......................................................................................................................50

5.2.1 Management Oversight.....................................................................................................51

5.2.2 Operator Training .............................................................................................................52

5.2.3 Auditing of Inspection Procedures....................................................................................52

5.2.4 Auditing of Schedules.......................................................................................................53
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5.2.5 Source of Corrosion ..........................................................................................................54

5.3 Emergency Management ...............................................................................................................55

5.3.1 Facility Requirements .......................................................................................................56

5.3.2 DPC Emergency Response Plan .......................................................................................56

5.3.2.1 Community Notification....................................................................................57

5.3.2.2 Designation of Responsibilities.........................................................................59

5.3.2.3 Emergency Response Assessment.....................................................................60

5.3.2.4 Training, Audits, and Drills...............................................................................60

5.3.2.5 Emergency Response Equipment ......................................................................61

5.3.2.6 Post-Incident Remediation ................................................................................63

5.3.2.7 Other Issues .......................................................................................................63

5.3.3 Community Emergency Response Requirements.............................................................64

5.3.4 Community Emergency Response Plan............................................................................65

5.3.4.1 Community Notification....................................................................................66

5.3.4.2 Community Emergency Preparedness...............................................................66

5.4 The Chlorine Institute Recommended Practices............................................................................68

5.5 NACD Responsible Distribution Process ......................................................................................69

6.0 ROOT AND CONTRIBUTING CAUSES....................................................................................71

6.1 Root Causes ...................................................................................................................................71

6.2 Contributing Causes.......................................................................................................................72

7.0 RECOMMENDATIONS...............................................................................................................74

8.0 REFERENCES ..............................................................................................................................79

APPENDIX A: Dry Chlorine Corrosion....................................................................................................82

A.1 Definition.......................................................................................................................................82
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A.2 Corrosion Mechanism....................................................................................................................82

A.3 Sources of Corrosion......................................................................................................................83

APPENDIX B: Additional Details on DPC Festus Facility.......................................................................86

B.1 Facility Layout...............................................................................................................................86

B.2 Chlorine Repackaging Process ......................................................................................................86

B.3 Tank Car Specification ..................................................................................................................90

B.4 Repackaging System Standby and Shutdown Modes....................................................................90

B.5 DPC Hose Order Arrangement ......................................................................................................91

APPENDIX C: Inspection, Schedule for Chlorine Repackaging System..................................................93

APPENDIX D: Critical Elements of Emergency Response Plan ..............................................................94

APPENDIX E: Fault Tree Analysis, Hose Failure ....................................................................................96

APPENDIX F: Causal Factors Diagram, Chlorine Release.......................................................................98
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Figures and Tables 

Figures 

1 Railroad Tank Car Unloading Station #3.......................................................................................13 

2 Failed Stainless-Steel Transfer Hose .............................................................................................13 

3 Schematic of 150-Pound Cylinder .................................................................................................19 

4 Schematic of 1-Ton Container .......................................................................................................19 

5 DPC Festus Facility Layout...........................................................................................................20 

6 Aerial View of DPC Festus Facility and Surrounding Area..........................................................22 

7 Schematic of Tank Car Protective Dome, Angle Valves, and Pressure Relief Device..................24 

8 Schematic of Excess Flow Valve...................................................................................................25 

9 Typical Fully Assembled Chlorine Transfer Hose ........................................................................26 

10 Typical Chlorine Transfer Hose Layers.........................................................................................26 

11 ESD Valve and Actuator................................................................................................................27 

12 Schematic of ESD Valve Arrangement at Unloading Station .......................................................28 

13 Actuator Indicator Showing Position of Valves ............................................................................28 

14 Chlorine Release at Tank Car Station #3.......................................................................................30 

15 ESD Panel With Emergency Shutdown Button.............................................................................31 

16 Movement of Chlorine Plume Offsite............................................................................................33 

17 HAZMAT Personnel Accessing the Top of Tank Car to Close Valves ........................................36 

18 Cleanup Area Around Tank Car Station #3...................................................................................37

19 Ruptured Chlorine Transfer Hose at Tank Car Station #3.............................................................38 

20 Structural Braid Layer Pulled Back to Expose Teflon Inner Liner ...............................................39 

21 Ruptured Hose and Piece of Teflon Inner Liner ............................................................................40 
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Figures and Tables (cont’d) 

22 Positioning of ESD Valves at Time of Release .............................................................................42 

23 Schematic of ESD Valve ...............................................................................................................44 

24 Identical Appearance of C-276 and 316-L Stainless-Steel Structural Braiding.............................47 

25 Corrosion Buildup in Chlorine Repackaging Piping Systems .......................................................55 

26 Truck Loading Station at DPC Festus ...........................................................................................58 

B-1 Pad Air Supply Assembly..............................................................................................................87 

B-2 Piping Assemblies for Tank Car Unloading ..................................................................................89 

B-3 DPC Festus Purchase Order for Flex Hose for Chlorine Railcar and Truck Unloading................92 

Tables 

1 Repackaging System Components in Standby and Shutdown Modes...........................................30 

C-1 Chlorine Repackaging System Inspection Schedule......................................................................93 
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Acronyms and Abbreviations 

AMS American Society for Metals 

API American Petroleum Institute 

ATSDR Agency for Toxic Substances and Disease Registry 

CCPS Center for Chemical Process Safety 

CFR Code of Federal Regulations 

CSB U.S. Chemical Safety and Hazard Investigation Board 

CTH Chlorine transfer hose 

DOT U.S. Department of Transportation 

EEI Engineering Evaluations Inspections, Inc. 

EMA Emergency Management Agency (Jefferson County) 

EPA U.S. Environmental Protection Agency 

EPCRA Emergency Planning and Community Right-to-Know Act 

ESD Emergency shutdown 

oF Degrees Fahrenheit 

FEMA Federal Emergency Management Agency 

FRA Federal Railroad Administration 

HAZCOM Hazard Communication Standard (OSHA) 

HAZMAT Hazardous materials 

HAZWOPER Hazardous Waste Operations and Emergency Response Standard (OSHA) 

HDPE High density polyethylene 

IDLH Immediately dangerous to life or health 

lb/hr Pounds per hour 
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Acronyms and Abbreviations (cont’d) 

LEPC Local emergency planning committee 

LTA Less than adequate 

MDNR Missouri Department of Natural Resources 

mg/L Milligrams per liter 

MI Mechanical integrity 

mph Miles per hour 

MSDS Material safety data sheet 

NACD National Association of Chemical Distributors 

NAHAD National Association of Hose and Accessories Distributor 

NIOSH National Institute for Occupational Safety and Health

NRT National Response Team 

OSHA Occupational Safety and Health Administration 

PMI Positive materials identification 

PPE Personal protective equipment 

ppm Parts per million 

psig Pound per square inch gage 

PSM Process Safety Management Standard (OSHA) 

PVC Polyvinyl chloride 

PVDF Polyvinylidene fluorid 

QA Quality assurance 

RCRA Resource Conservation and Recovery Act 

RDP Responsible Distribution Process (NACD) 
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Acronyms and Abbreviations (cont’d) 

RMP Risk Management Program (EPA) 

SARA Superfund Amendments and Reauthorization Act 

SCBA Self-contained breathing apparatus 

SPCC Spill Prevention, Control, and Countermeasures (Oil Pollution Act) 

XRF X-ray fluorescence 
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Executive Summary 

On the morning of August 14, 2002, 48,000 pounds of chlorine was released over a 3-hour period during 

a railroad tank car unloading operation at DPC Enterprises, L.P., near Festus, Missouri. The facility 

repackages bulk dry liquid chlorine into 1-ton containers and 150-pound cylinders for commercial, 

industrial, and municipal use in the St. Louis metropolitan area. 

Chlorine is a toxic chemical. Concentrations as low as 10 parts per million are classified as “immediately 

dangerous to life or health” (NIOSH, 2003). Although the wind direction on the day of the release carried 

the majority of the chlorine plume away from neighboring residential areas, some areas were evacuated. 

Sixty-three people from the surrounding community sought medical evaluation at the local hospital for 

respiratory distress, and three were admitted for overnight observation. The release affected hundreds of 

other nearby residents and employees, and the community was advised to shelter-in-place for 4 hours. 

Traffic was halted on Interstate 55 for 1.5 hours. Three DPC workers received minor skin exposure to 

chlorine during cleanup activities. 

This incident began with the failure of a chlorine transfer hose (CTH) connecting a tank car to the facility 

repackaging process. The U.S. Chemical Safety and Hazard Investigation Board (CSB) determined that 

the ruptured hose was constructed of stainless-steel braid rather than Hastelloy C, a metal alloy (CSB, 

2002). The CSB investigation determined the following root causes: 

• The DPC quality assurance (QA) management system did not have adequate provisions to ensure 

that chlorine transfer hoses met required specifications prior to installation and use. 

• Branham Corporation, the CTH fabricator/distributor, did not have a QA management system to 

ensure that fabricated hose complied with customer specifications or that its own certification of 

materials specifications were correct. 
DPC Festus 05-30-03 

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• The DPC testing and inspection program did not include procedures to ensure that the process 

emergency shutdown system would operate as designed. 

In addition, the following factors were contributing causes: 

• The hose identification system of CTH manufacturers is inadequate to provide continuous 

positive identification of similar-looking structural braiding materials of construction, such as 

Hastelloy C and stainless steel. 

• The DPC mechanical integrity program failed to detect corrosion in the chlorine transfer and pad 

air systems before it caused operational and safety problems. 

• The overall emergency response and planning system had serious deficiencies: 

- The community notification system was inefficient, which resulted in additional exposure 

to neighboring residents and businesses. 

- DPC emergency preparedness planning was deficient. 

- Jefferson County community emergency preparedness planning was inadequate for an 

incident of this magnitude. 

CSB makes recommendations to DPC Enterprises, Festus; DX Distribution Group (DPC corporate); 

Branham Corporation; Jefferson County Emergency Management Agency; Missouri State Emergency 

Response Commission; Missouri Department of Natural Resources; Agency for Toxic Substances and 

Disease Registry; The Chlorine Institute, Inc.; National Association of Hose and Accessories Distributors; 

and National Association of Chemical Distributors. 
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1.0 Introduction 

1.1 Background 

Around 9:20 am on Wednesday, August 14, 2002, a 1-inch chlorine transfer hose (CTH) used in a 

railroad tank car unloading operation at the DPC Enterprises, L.P., facility, near Festus, Missouri, 

catastrophically ruptured (Figures 1 and 2). The facility is located in an unincorporated area of Jefferson 

County. The hose rupture initiated a sequence of events that led to the release of 48,000 pounds of 

chlorine. The release continued unabated for nearly 3 hours. 

 

Figure 1. Railroad tank car unloading station #3. 

Figure 2. Failed stainless-steel transfer hose. 
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Chlorine is a toxic chemical. When inhaled in high concentrations, chlorine gas causes suffocation, 

constriction of the chest, tightness in the throat, and edema of the lungs. At around 1,000 parts per 

million (ppm),1

 it is likely to be fatal after a few deep breaths. According to the National Institute for 

Occupational Safety and Health (NIOSH, 2003), chlorine gas concentrations of 10 ppm are classified as 

"immediately dangerous to life or health" (IDLH). Depending on a number of factors—such as release 

volume, terrain, temperature, humidity, atmospheric stability, and wind direction and speed—a chlorine 

gas plume can travel several miles in a short time at concentrations well above IDLH. 

DPC Festus is located 35 miles south of downtown St. Louis and 3 miles south of both the Festus and 

Crystal City town centers. Festus and Crystal City have a combined population of 14,000. CSB 

estimates that 1,500 people live and work within a 1-mile radius of DPC. Although about 200 people live 

adjacent to DPC in the Blue Fountain mobile home park, the release occurred primarily downwind of the 

park, with the majority of the plume traveling east-to-southeast. 

The majority of residents of the mobile home park were at work on the morning of August 14. 

Nevertheless, 63 people from the surrounding community sought medical evaluation at the local hospital; 

three persons were admitted and released the following day. Three workers also received minor skin 

exposure to chlorine during cleanup activities after the release. 

The U.S. Chemical Safety and Hazard Investigation Board (CSB) investigated this incident for the 

following reasons: 

• The large quantity of release and prolonged duration, with potential catastrophic offsite 

consequences to the public. 

 

1

 1,000 parts of chlorine per million parts of air. 
DPC Festus 05-30-03 

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• The wide use of chlorine within the United States and the potential for similar incidents at 

other facilities. 

1.2 Investigative Process 

CSB investigators arrived at the facility on the morning of August 15. CSB conducted interviews with 

DPC employees and members of the community, reviewed relevant company documents and scientific 

literature, and examined physical evidence. CSB also arranged for testing of the ruptured hose and 

critical elements of the process emergency shutdown (ESD) system (EEI Inc., 2003) and for dispersion 

modeling of the chlorine plume (Trinity Consultants, 2003). 

To obtain information on the CTH manufacturing and supply process, CSB investigators visited Branham 

Corporation and Crane-Resistoflex. In addition, CSB visited another chlorine repackaging facility (DXI 

Industries, Inc.), in Houston, Texas, to evaluate chlorine handling procedures. CSB also contacted other 

chlorine repackagers and reviewed recommended practices of The Chlorine Institute, Inc. 

Other investigative organizations onsite included the Occupational Safety and Health Administration 

(OSHA), U.S. Environmental Protection Agency (EPA), and U.S. Department of Transportation–Federal 

Railroad Administration (DOT–FRA). 

Under a Memorandum of Understanding, the Agency for Toxic Substances and Disease Registry 

(ATSDR) assisted CSB in investigating emergency and medical response to the incident. 

1.3 Characteristics, Use, and Hazards of Chlorine 

1.3.1 Characteristics 

In 2002, 12.7 million tons of chlorine was manufactured in the United States. Chlorine is produced by 

passing an electrical current through a salt solution or melted salt, which splits the salt molecules. 
DPC Festus 05-30-03 

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Chlorine gas can be liquefied by the application of pressure at reduced temperatures to form a clear, 

amber-colored liquid. Liquid chlorine (a liquefied compressed gas) is more economical to ship and store. 

Other than at large production facilities, liquid chlorine is typically stored and shipped in 150-pound 

cylinders, 1-ton containers, or 55- and 90-ton tank cars. One volume of liquid chlorine, when vaporized, 

yields about 460 volumes of gas. The release and vaporization of liquid chlorine from its pressurized 

containment often condenses the moisture in air, creating a highly visible fog. Chlorine gas is 2.5 times 

heavier than air and tends to float near the ground. 

Chlorine is referred to as either dry or wet, depending on its moisture (water vapor in air) content. DPC 

Festus repackaged dry liquid chlorine (Appendix A). Below 250 degrees Fahrenheit (oF), common metals 

such as carbon steel, copper, lead, nickel, and brass are resistant to dry chlorine from a corrosion 

standpoint. However, in the presence of water/moisture, dry chlorine is very corrosive to most common 

metals. 

1.3.2 Products and Safe Handling 

Chlorine has a variety of uses—ranging from household bleach, water disinfectants, and the manufacture 

of pesticides to medicines, bullet-resistant vests, plastic piping, silicon chips, automotive parts, and many 

other products. 

Because of chlorine's characteristics and widespread use, safety has long been a focus of producers, 

packagers, distributors, and users. Chlorine handlers look to The Chlorine Institute to provide leadership 

and continuous improvements in chlorine safety. DPC is a member of The Chlorine Institute. 
DPC Festus 05-30-03 

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1.3.3 Health Hazards 

At room temperature, chlorine is a greenish-yellow gas. Its very pungent and irritating bleach-like odor 

provides warning of high concentrations. Chlorine gas can be detected by smell at concentrations well 

below 1 ppm. 

Chlorine exposure occurs through inhalation or through skin or eye contact. Inhalation of larger amounts 

irritates the mucous membranes of the eyes, nose, throat, and lungs. Prolonged exposure or exposure to 

high concentrations may be fatal, as outlined below (Ellenhorn and Barceloux, 1988): 

• 1-3 ppm: mild mucous membrane irritation 

• 5-15 ppm: moderate irritation of upper respiratory tract 

• 30 ppm: immediate chest pain, vomiting, dyspnea, and cough 

• 40-60 ppm: toxic pneumonitis and pulmonary edema. 

• 430 ppm: lethal over 30 minutes

• 1,000 ppm: death within a few minutes. 

Although inhalation is the primary mode of exposure, direct skin contact with gaseous or liquid chlorine 

may result in chemical burns as the chlorine reacts with moisture on the skin. In addition, the extremely 

cold temperatures associated with liquid chlorine and vaporized gas escaping from pressurized 

containment can cause frostbite. 

OSHA and EPA regulate the manufacture, storage, and use of chlorine. The OSHA Process Safety 

Management (PSM) standard requires compliance with a variety of provisions designed to protect 

workers at facilities that handle chlorine in amounts greater than 1,500 pounds (29 CFR 1910.119, 
DPC Festus 05-30-03 

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Appendix A). Similarly, one of the objectives of the EPA Risk Management Program (RMP) rule is to 

protect the public from facilities that handle more than 2,500 pounds of chlorine (40 CFR 68.130). 

1.4 DPC Enterprises Festus Facility 

AG Kit Chemical Company initially developed the Festus site in 1960. Jones Chemical Company 

acquired it in 1972 and constructed the chlorine repackaging facility (Figure 5). In August 1998, DPC 

Enterprises bought the facility from Jones Chemical; it upgraded the chlorine repackaging process design 

to include area chlorine detectors and an ESD system (Appendix B). 

DPC Enterprises owns and operates the Festus repackaging facility, five other similar facilities, and two 

warehouses. It is part of the DX Distribution Group network of 18 repackaging and distribution 

companies. Technical expertise is provided to the various sites through DX Distribution Group 

headquarters. 

DPC Festus is located on an 8-acre site in the Plattin Creek Valley of Jefferson County, at 1785 Highway 

61. The facility receives bulk dry liquid chlorine in 90-ton tank cars and repackages it into 150-pound 

cylinders and 1-ton containers for commercial, light industrial, and municipal use (Figure 3 and 4). DPC 

Festus employs 12 full-time personnel—four packaging operators (packagers), four truck drivers, two 

administrative staff, a sales representative, and an operations manager. 

The chlorine repackaging process is a one-shift operation, typically running from 6:00 am to 4:00 pm, 

Monday through Friday. At the end of the day, a packager climbs the ladder to the top of the tank car and 

closes all car valves manually. Residual chlorine in the piping system is directed to the bleach production 

process. A vacuum is pulled and the system is left under negative pressure. As a final step, the ESD 

button is pressed to close all ESD valves (see Section 2.4). The chlorine transfer hoses remain connected 
DPC Festus 05-30-03 

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to the tank car overnight. Leak testing (by spraying small amounts of ammonia solution around possible 

leak points) is performed prior to startup the next day. 

 

Figure 3. Schematic of 150-pound cylinder. 

Figure 4. Schematic of 1-ton container. 
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Figure 5. DPC Festus facility layout. 

1.5 Surrounding Community 

Various businesses and residential areas surround the DPC Festus facility (Figure 6): 

• Blue Fountain residential mobile home park, consisting of about 100 homes, is directly 

adjacent to the southwest. 
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• Goodwin Brothers Construction and Intermodal Tire Retreading are located about 100 feet to 

the east, separated from DPC by Highway 61. Each business has about 18 full-time 

employees. 

• A farm is located just to the north, separated from the site by railroad tracks. 

• Several other residential areas and businesses—as well as the Jefferson Memorial Hospital 

system, including a hospital, assisted-living facility, child care center, cancer treatment 

center, and medical offices; St. Pius High School; and Festus–Crystal City Airport—are 

located within a 1-mile radius of the facility. 

Plattin Creek, which flows into the Mississippi River 5 miles to the east, is located about 500 feet to the 

south. Interstate 55 is located less than 0.5 mile to the east. 

 
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Figure 6. Aerial view of DPC Festus facility and surrounding area. 
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2.0 Chlorine Repackaging Process 

2.1 Process Overview 

The chlorine repackaging process operation involves the following: 

• Connecting a 90-ton (180,000 pounds) chlorine tank car to one of three unloading stations. 

• Transferring liquid chlorine from the tank car through the process piping system to filling 

stations. 

• Loading the filled 150-pound cylinders and 1-ton containers onto trucks for distribution. 

• Cleaning and preparing empty cylinders and containers for reuse. 

In addition to repackaging chlorine, the Festus facility also runs a continuous bleach manufacturing 

process. 

2.2 Chlorine Tank Cars 

A chlorine tank car has four manually operated angle valves and a spring-loaded pressure relief device 

mounted within a protective dome (Figure 7). Valves A and C on the longitudinal centerline of the tank 

car are used for liquid chlorine discharge; valves B and D on the transverse centerline are connected to the 

vapor space (Figure 7). At DPC Festus, valve D supplied air (also referred to as “pad air”) to pressurize 

the tank car during chlorine unloading; valve B was not in use. The valve openings on a chlorine tank car 

have a 1-inch inside diameter. 
DPC Festus 05-30-03 

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Figure 7. Schematic of tank car protective dome, angle valves, and pressure relief device. 

An excess flow valve,2 which consists of a rising ball that closes when the rate of flow exceeds 15,000 

pounds per hour (lb/hr), is located beneath each liquid valve (Figure 8). Liquid chlorine is withdrawn 

from inside the tank car through eduction pipes3

 attached to the excess flow valves. 

Appendix B describes the tank car chlorine unloading procedures and assemblies, and the pad air and 

instrument air systems used in the repackaging process. 

 

2

 An excess flow valve is designed to stop the flow of material when the flow rate exceeds a preset limit. This 

device is used to prevent large releases during material transport. During normal operation, the excess flow valve 

remains open. 

3

 An eduction pipe is used to unload liquid material. It is a long steel pipe attached to the liquid valve and extends to 

the bottom of the tank car. 
DPC Festus 05-30-03 

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Figure 8. Schematic of excess flow valve. 

2.3 Chlorine Transfer Hose 

Although the DPC Festus facility has three chlorine tank car unloading stations, only one tank car is 

unloaded at a time. Each unloading station is equipped with three chlorine transfer hoses, each 

approximately 11 feet in length and 1 inch in diameter (Figure 9). DPC specifications call for each hose 

assembly to be constructed of a Teflon inner liner (plastic), a Hastelloy C-276 structural reinforcement 

braid layer (metal) for pressure containment, and a high-density polyethylene (HDPE) spiral guard for 

abrasion protection (Figure 10). DPC uses no other transfer hose assemblies with similar dimensions for 

chlorine tank car unloading or for any other operation within the repackaging process. 

2.4 Emergency Shutdown System 

The DPC Festus ESD system is designed to shut off accidental releases of chlorine from the repackaging 

system. Chlorine detectors and automatic air-actuated ball valves (ESD valves) at the unloading stations 

are critical components of the ESD system (Figure 11), which is activated either automatically or 
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Figure 9. Typical fully assembled chlorine transfer hose. 

Figure 10. Typical chlorine transfer hose layers. 
DPC Festus 05-30-03 

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manually by pressing one of several ESD buttons located throughout the facility.4

 At concentrations of 5 

ppm, the chlorine detectors trigger flashing lights and sound an audio alarm. At concentrations of 10 

ppm, the ESD valves are automatically activated along with a second higher decibel audio alarm. 

Figure 11. ESD valve and actuator. 

Tank car station #3 is equipped with a chlorine detector. Each tank car station is also equipped with five 

ESD valves—three on the tank car side as part of the air supply and chlorine unloading assemblies, and 

two on the plant side piping (Figure 12). Air-operated actuators mounted on top of the valves open and 

close the valves. Indicators on the actuators show the positioning of the valves (Figure 13). When highlevels of chlorine are detected or the ESD system is manually activated, the solenoids5

 controlling the 

actuators are deenergized—which causes the ESD valves to close, shutting down the chlorine flow. 

 

4

The air actuators used at DPC contain a piston in a housing. A spring holds the piston in one position, while air 

pressure on the other side of the chamber pushes the piston against the spring, which in turn moves the valve stem 

through a series of gears. If air pressure is suddenly lost, the spring pushes against the piston to push the valve to the 

close position. All the valves are controlled off the same central system. 

5

At the instant the external force (electricity) is removed, the magnetic field vanishes and shuts off air to the 

actuators. 
DPC Festus 05-30-03 

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Figure 12. Schematic of ESD valve arrangement at unloading station. 

Figure 13. Actuator indicator showing position of valves. 

The ESD system is manually activated at the end of each day as part of normal shutdown procedures. 

However, DPC standard operating procedures do not require packagers to verify that the indicators show 

actual closure of the ESD valves. 
DPC Festus 05-30-03 

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3.0 Description of Incident 

3.1 Pre-Incident Events 

3.1.1 Operations at Tank Car Station #3 

On August 12, 2002, a tank car containing 180,000 pounds6 of chlorine was connected to station #3, 

which served all chlorine filling operations until the time of the release on August 14. The facility 

repackaging production records indicate that the car contained 80,000 pounds of chlorine at the time of 

the incident. It was later determined that 48,000 pounds of chlorine had been released.7

3.1.2 Repackaging System Standby and Shutdown Modes 

The chlorine repackaging system is on standby during morning and afternoon breaks, lunch, and cylinder 

changeouts. When all cylinder filling operations are complete for the day, the system is shut down (Table 

1). In both standby and shutdown modes, the chlorine transfer hoses remain connected to the tank car. 

Appendix B describes DPC procedures for standby and shutdown modes. 

3.2 The Incident 

3.2.1 The Release 

At about 6:30 am on August 14, four DPC packagers, a truck driver, and the operations manager8 started 

up chlorine filling and container preparation operations for the day. Around 9:00 am, these employees 

placed the repackaging system on standby mode and took their morning break. Two of the packagers and 

the truck driver went to the designated smoking area outside the repackaging building; the others 

 

6

 The DOT load limit for the chlorine tank car is 180,000 pounds (90 tons). 

7

 Weight of tank car prior to release minus weight of car after the release (80,000 –32,000 = 48,000). 

8

 The operations manager had various responsibilities, including assisting packagers with cylinder filling operations. 
DPC Festus 05-30-03 

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remained in the breakroom. At approximately 9:20 am, the three men outside heard a loud pop and 

observed a continuous release of chlorine at tank car station #3 (Figure 14). They immediately evacuated 

the area. 

Table 1 

Repackaging System Components in Standby and Shutdown Modes 

Repackaging System 

Components 

 Standby Mode Shutdown Mode 

150-lb and 1-ton fill station valves Closed Closed 

ESD valves Open Closed 

Tank car manual valves Open Closed 

System piping Contains chlorine No chlorine 

 KTVI-TV, St. Louis, Missouri 

Figure 14. Chlorine release at tank car station #3. 

The leak activated an area chlorine detection monitor audio alarm. Upon hearing the alarm, the 

employees in the breakroom tried to identify the source of the leak. They found chlorine entering the 

repackaging building through an open access door near tank car station #3. Because of the apparent 
DPC Festus 05-30-03 

31 

magnitude and intensity of the release, the employees evacuated the building. The operations manager 

pushed the ESD button (Figure 15) as he exited in an attempt to manually shut off the chlorine release. 

Figure 15. ESD panel with emergency shutdown button. 

3.2.2 ESD Valve Failure 

The chlorine repackaging system ESD valves are intended to close either automatically based on chlorine 

detection levels or through hand-operated ESD buttons. Although both methods were activated during 

the incident, several critical ESD valves failed to close, which allowed the release to continue unabated. 

The ESD system was not designed to provide a signal of actual valve closure. 

3.2.3 Tank Car Excess Flow Valve 

According to The Chlorine Manual, an excess flow valve: 

. . . Is designed to close automatically against the flow of liquid chlorine if the angle valve is 

broken off in transit. It may close if a catastrophic leak involving a broken connection occurs but 

it is not designed to act as an emergency shut-off device during transfer (Chlorine Institute, 1997; 

p. 14). 
DPC Festus 05-30-03 

32 

The tank car excess flow valves were designed to close only if the flow rate exceeds their set point 

(15,000 lb/hr). These valves remained open during the release. 

3.2.4 Access to Emergency Response Equipment 

DPC had four self-contained breathing apparatus (SCBA) units in addition to other emergency response 

equipment. The packagers (who also served on the facility emergency response team) were trained on 

use of the SCBA and on how to respond to a chlorine release. However, because the equipment was not 

adequately maintained or organized inside the repackaging building, the men were unable to gather it as 

they exited the building. 

3.2.5 Facility Evacuation 

The nine DPC personnel working on August 14, including two administrative staff and one salesperson, 

evacuated the facility through the front entrance around 9:30 am. All but two of the employees drove 

north on Highway 61 to an assembly point 1 mile away, as predetermined in the emergency plan. The 

operations manager established radio contact with the two employees who drove south on Highway 61. 

3.2.6 Community Notification 

DPC Festus had no community sirens or other community-wide alert systems to notify neighboring 

residents and businesses of a release. 

Wind speed was generally 3 to 5 miles per hour (mph) on the morning of August 14. The chlorine plume 

(Figure 16) moved primarily east-to-southeast in the direction of Goodwin Brothers Construction and 

Intermodal Tire, though it is likely that it migrated into the adjacent Blue Fountain mobile home park 
DPC Festus 05-30-03 

33 

when there was no wind. As indicated by dispersion modeling,9

 chlorine concentrations of 3 ppm could 

have extended to approximately 3.7 miles from the point of release (Trinity Consultants, 2003). 

KTVI–TV, St. Louis, Missouri 

Figure 16. Movement of chlorine plume offsite. 

The owner of Goodwin Brothers and an employee at Intermodal Tire saw the approaching chlorine 

plume. These two businesses share a parking lot that accesses Highway 61. By the time all employees 

were notified, the plume had migrated across the highway and was moving over the parking lot, close to 

the ground. Several employees drove through the plume and had to seek medical evaluation. Neither of 

the businesses had an alternative escape route. 

Hundreds of residents—including occupants of an assisted living facility and a learning center, both part 

of the Jefferson Memorial Hospital system; and students at a local school—were sheltered-in-place for up 

to 4 hours. Interstate 55 traffic was shut down for 1.5 hours, from 9:45 to 11:15 am. A total of 63 people 

in the surrounding community sought medical evaluation because of inhalation exposure to chlorine. 

 

9

 Dispersion modeling represents the possible behavior of the plume; results may vary depending on the model. 
DPC Festus 05-30-03 

34 

Eight persons were administered oxygen. Three persons were kept overnight at Jefferson Memorial 

Hospital for observation of possible chlorine-induced pneumonia and were released the next day. 

In addition, the chlorine caused tree leaves and other vegetation around the facility and in the plume path 

to turn brown. The release did not appear to affect water quality in Plattin Creek (MDNR, 2002). The 

chlorine plume continued generally eastward along Plattin Creek Valley before dissipating. 

3.2.7 Emergency Response 

At 9:27 am—approximately 7 minutes after the release began—the DPC operations manager called 9-1-1 

to report the chlorine release. The Jefferson County R-7 volunteer fire department arrived on scene 

within 10 minutes. The R-7 fire chief immediately requested 9-1-1 dispatch to notify mutual aid response 

fire departments and the Jefferson County hazardous materials (HAZMAT) unit. A reconnaissance team 

of R-7 fire-fighters was sent to Goodwin Brothers, Intermodal Tire, and DPC to search for victims; all 

employees had evacuated the area. The R-7 fire department also initiated evacuation of residents from 

the Blue Fountain mobile home park. 

Highway 61 was shut down in both directions. Two separate command posts were set up on the highway 

(one by municipal authorities and the other by county responders). Emergency response personnel from 

the north post notified the Jefferson Memorial assisted living facility and the learning center and St. Pius 

High School to shelter-in-place. The Jefferson County R-7 fire department, Jefferson County sheriff’s 

department, Missouri State Highway Patrol, Joaquin Plattin Ambulance Service, and several mutual aid 

fire departments staged at the south post. 

A drive-through “bull horn” notification, followed by door-to-door evacuation, was conducted at Blue 

Fountain mobile home park and the Howe Crossing residential area. It took emergency response 

personnel over 1 hour to evacuate the areas. The sheriff’s department and the highway patrol shut down 

Interstate 55. The ambulance service transported six people from neighboring areas with symptoms of 
DPC Festus 05-30-03 

35 

chlorine exposure to Jefferson Memorial. The majority of people seeking medical evaluation drove to the 

hospital, which is located 1 mile north of the DPC facility. The release continued unabated for nearly 3 

hours until HAZMAT personnel closed the tank car valves. 

The Jefferson County HAZMAT unit is made up of all volunteers, who live and work in various parts of 

the 660-square-mile county. The team duty officer received notification of the DPC release from 9-1-1 

dispatch at 9:45 am, and the team was paged within 15 minutes. Although the south post was designated 

as the HAZMAT staging area, the response truck and several team members initially went to the north 

post. Decontamination setup began at 11:00 am. Most of the team had arrived on scene by 11:15 am. 

It took 45 minutes to complete medical monitoring; entry team selection; and site safety planning, 

including entry and exit; and to don personal protective equipment (PPE). HAZMAT responders 

measured chlorine concentrations of greater than 1,000 ppm at the release site, which is life threatening 

without proper respiratory equipment. 

Three HAZMAT personnel and one DPC employee (who had specialized HAZMAT training) entered the 

release area around noon, where a yellowish-green fog about 4 feet high covered the area surrounding the 

tank car. Visibility was very poor. Two HAZMAT personnel climbed the tank car ladder to access the 

top of the car (Figure 17). They closed the liquid valve that supplied the ruptured hose (valve A), but the 

release did not stop. They then closed the other liquid valve (valve C) and vapor valve D halfway; then 

they completely closed both valves. The release stopped when valve C was closed. 

The HAZMAT team surveyed the area surrounding the tank car and the repackaging building for other 

release sources. None were located. They identified a 4- by 4-foot formation of chlorine hydrate10 next 

to the tank car (underneath the ruptured hose), but it was determined to pose no imminent danger. 

 

10 Chlorine ice or chlorine hydrate (Cl2–8H2O) may crystallize below 49o F at atmospheric pressure and at higher 

temperatures at increased pressure. 
DPC Festus 05-30-03 

36 

KTVI–TV, St. Louis, Missouri 

Figure 17. HAZMAT personnel accessing the top of tank car to close valves. 

A majority of the emergency responders left the scene after the release was stopped. However, Highway 

61 remained closed, and the evacuation order stayed in effect due to high levels of chlorine. Over the 

next several hours, the State of Missouri Department of Natural Resources conducted monitoring 

throughout the facility as well as the neighboring community (MDNR, 2002). Around 5:00 pm, the 

Jefferson County R-7 fire department lifted the evacuation order and reopened Highway 61. 

3.2.8 Cleanup Activities 

DPC began cleanup activities immediately after the R-7 fire department released the scene. Figure 18 

shows the area of cleanup. Alarms were turned off, the chlorine piping system was evacuated and 

depressurized, and all fill stations were isolated. 
DPC Festus 05-30-03 

37 

Figure 18. Cleanup area around tank car station #3. 

In consultation with DPC corporate personnel, the operations manager decided to remediate the chlorine 

hydrate formation. No remediation plan was developed to formally review potential hazards. Three of 

the DPC packagers, wearing chlorine-resistant suits and carrying escape respirators, placed lime (calcium 

carbonate) on top of and around the ice formation. However, the material was not fully neutralized when 

the packagers attempted to place it into drums. The trapped liquefied chlorine was exposed to warm air 

and released as a gas. 

The protective suits worn by the packagers provided only minimal protection because they were not fully 

encapsulating. The three men received minor skin exposure, and experienced numbness, itching, and 

irritation of affected skin. Direct contact with liquefied chlorine gas is known to cause such effects 

because of mild-to-severe frostbite. All three men received medical evaluation. 

The hydrate formation continued to give off minor amounts of chlorine gas for the next 2 days until an 

environmental remediation company completed the cleanup. 
DPC Festus 05-30-03 

38 

4.0 Reconstructive Analysis 

The catastrophic rupture of a 1-inch transfer hose attached at tank car station #3 initiated the chlorine 

release (Figure 19). Reconstructive analysis determined why the chlorine transfer hose ruptured and why 

the ESD valves failed to close. The excess flow valves were dismantled and inspected to determine if 

they should have closed. 

Figure 19. Ruptured chlorine transfer hose at tank car station #3. 

4.1 Hose Construction 

The CTH assembly used at DPC Festus was specified to be constructed of a Teflon inner liner, a 

Hastelloy C-276 structural reinforcement braid layer for pressure containment, and an HDPE spiral guard 

for external protection,11 as discussed in Section 2.3. Although hoses with nonmetallic12 cores, such as 

Teflon, are more tolerant of moisture, they are subject to permeation by chlorine molecules. To ensure 

 

11 The design specifications of the CTH assembly met recommended practice guidelines of The Chlorine Institute. 

12 Most plastics react chemically with chlorine because of their hydrocarbon structural makeup. This reactivity is 

avoided with some plastics in which fluorine atoms are substituted into the hydrocarbon molecule (e.g., Teflon). 

Rupture point
DPC Festus 05-30-03 

39 

structural integrity, The Chlorine Institute (1998) recommends that hoses with such inner lining “have a 

structural layer braid of polyvinylidene fluoride (PVDF) monofilament material or a structural braid of 

Hastelloy C-276” 13 (Figure 20). 

Figure 20. Structural braid layer pulled back to expose Teflon inner liner. 

4.2 Hose Rupture 

The rupture occurred in the chlorine transfer hose attached to tank car valve A, about 3.5 feet from its 

connection to the tank car (Figure 21). CSB investigators found a 2.5-inch-long segment of the hose 

inner liner and several pieces of the structural braiding scattered throughout the immediate area. The 

external spiral guard kept the ruptured hose attached to both the tank car and the plant piping. 

The ruptured hose and the other two intact hoses at tank car station # 3 were removed from service and 

sent to a St. Louis laboratory for inspection and testing. 

 

13 PVDF and Hastelloy C-276 can resist corrosion from exposure to both dry chlorine in the presence of moisture 

and wet chlorine. 
DPC Festus 05-30-03 

40 

 

Figure 21. Ruptured hose and piece of Teflon inner liner. 

4.3 Metallurgical Examination 

The HDPE spiral guards around each of the three hoses were cut off, and each hose was visually 

inspected. The structural braid layer of the intact hoses showed no signs of deterioration or discoloration; 

however, the structural braiding of the ruptured hose was significantly corroded, as evidenced by brown 

discoloration and granular flakes. The inner liner of the ruptured hose showed no sign of deterioration. 

Materials testing of the structural braiding of both the ruptured hose and one of the intact hoses revealed 

that the ruptured hose braid layer was constructed of 316L stainless steel and the braid layer of the intact 

hose was constructed of Hastelloy C-276. As discussed in Section 4.1, nonmetallic inner liners (e.g., 

Teflon) must be reinforced with chlorine-resistant outer layers. 

Once the hose was put into service at tank car station # 3, atmospheric moisture in combination with 

permeating chlorine molecules from the Teflon inner liner caused the 316L stainless-steel braid layer to 

corrode. Thus, CSB concludes that the hose ruptured because its stainless-steel structural braiding was 

inappropriate for chlorine transfer. 
DPC Festus 05-30-03 

41 

During chlorine unloading operations, the transfer hose is subjected to maximum operating pressures of 

about 175 pounds per square inch gage (psig). The hose also encounters bending forces during each 

connection/disconnection to the tank car. CSB concludes that corrosion of the 316L braid layer weakened 

the structural integrity of the hose. Normal operating pressure, in combination with repetitive bending 

forces, caused the hose to rupture and release chlorine. (See fault tree analysis of hose rupture in 

Appendix E.) 

4.4 ESD Valve Positioning 

Section 2.4 describes the DPC Festus ESD system. CSB investigators checked the indicators on all five 

ESD valves at tank car station #3 after the incident.14 Although both the automatic and manual ESD 

mechanisms were employed, four of the five valves failed to completely close and isolate the release (see 

Figure 22): 

• ESD valve #2, connected to the pad air supply, was fully open. 

• ESD valve #3, connected to the intact liquid line chlorine transfer hose, was 60 percent open. 

• Both ESD valves (#4 and 5) on the plant side piping were fully open. 

The one valve that did close was ESD valve #1, connected to the ruptured chlorine transfer hose. 

Determining the actual positioning of the five ESD valves at tank car station #3 led CSB investigators to 

conclude that the chlorine flowed through the partially opened ESD valve #3, to the attached intact liquid 

CTH line, into the plant side piping, and back through the ruptured hose (see Figure 22). Closing tank car 

 

14 Valves #1 and #3 were later dismantled to verify the actuator indicator readings and to determine valve 

positioning. 
DPC Festus 05-30-03 

42 

valve A did not stop the release because valve C continued to supply chlorine through the intact liquid 

CTH line. 

Figure 22. Positioning of ESD valves at time of release. 

The failure of ESD valve #2 to close and isolate the pad airflow supplied pressure to push chlorine out of 

the tank car during the release. DPC Festus had no other automatic mechanism to shut down the pad air 

system in an emergency. Such a mechanism may have slightly reduced the flow of chlorine from the tank 
DPC Festus 05-30-03 

43 

car; however, in any case, the vapor pressure of chlorine and the air pressure already in the tank car would 

have continued to provide sufficient force to push the chlorine out of the car. 

4.5 ESD System Testing 

The ESD system was tested to determine why ESD valves #2, 3, 4, and 5 failed to close. The chlorine 

detector at tank car station #3 and the system’s electrical circuitry were also examined, as well as the 

hand-operated ESD buttons. All solenoids controlling the ESD valve actuators were found to be 

deenergized prior to testing. Testing results are as follows: 

• The solenoids energized and deenergized properly. 

• Each ESD button functioned properly. 

• The instrument air hoses providing plant air to the actuators were found to be free of 

mechanical damage. 

CSB investigators thus eliminated the control system as a cause of the ESD valve failures. 

Testing of ESD valves # 3 and 4 revealed that the torque necessary to close the valves—in excess of 40 

foot-pounds—far exceeded the 5 foot-pounds available from the actuators. Visual inspection of both 

valves revealed corrosion product buildup around the valve balls (Figure 23); these deposits were found 

to be ferric chloride. CSB investigators recognized that some corrosion within the repackaging system, 

including the unloading piping assemblies, occurred after the release. Therefore, a second set of piping 

assemblies—not in use at the time of the incident—was inspected and tested; these assemblies were also 

found to have corrosion, and they did not close properly when activated. It was concluded that corrosion 

products impeded motion of the ESD valves. 
DPC Festus 05-30-03 

44 

The valve balls were constructed of Monel, which is resistant to moisture-induced corrosion in chlorine 

service. The corrosion products were determined to have migrated to the valves from the pad air supply 

and tank car assemblies, as well as from parts of the plant liquid and pad air carbon steel piping. 

Figure 23. Schematic of ESD valve. 

4.6 Excess Flow Valve 

The tank car excess flow valves were dismantled and examined for mechanical defects and corrosion; 

nothing was found that would have prevented the valves from closing. 

The rate of chlorine flow through the ruptured transfer hose was estimated to be 16,000 lb/hr,15 above the 

set point of 15,000 lb/hr. At this rate, the excess flow valves should have closed and stopped the release. 

(However, the intended use of excess flow valves on chlorine tank cars is to prevent releases during 

transport; they should not be relied upon to stop releases during unloading operations.) 

 

15 Assuming 48,000 pounds of chlorine over 3 hours. 
DPC Festus 05-30-03 

45 

Facility production records may have overestimated the amount of chlorine in the tank car. For example, 

if the tank car contained only 76,500 pounds of chlorine (instead of the 80,000 pounds), the estimated 

flow rate (44,500 lb/3 hr ≈ 14,800 lb/hr) would have been below the excess flow valve set point of 15,000 

lb/hr. The flow may have been reduced because: 

• ESD valve # 3 was only 60 percent open, which may have changed flow characteristics or 

created a drop in pressure. 

• The attachment of transfer assemblies and hoses can cause a decline in pressure, which would 

alter product release rates and flow characteristics. 
DPC Festus 05-30-03 

46 

5.0 Analysis of Incident 

5.1 Hose Failure 

5.1.1 Hose Supply Chain 

Since April 2000, Branham Corporation has been the sole supplier of chlorine transfer hose to DPC 

Festus. As a hose distributor, Branham purchases long rolls of raw hose and components (e.g., endfittings and HDPE spiral guards) and fabricates the hose according to customer requirements. CraneResistoflex is Branham’s only supplier of bulk quantity chlorine transfer hose.16 Other manufacturers, 

including Crane-Resistoflex, provide Branham with bulk raw hose (e.g., rubber, stainless steel) for use in 

transferring other materials. 

On March 18, 2002, DPC corporate headquarters ordered three 1-inch chlorine transfer hoses for tank car 

unloading operations at Festus. Appendix B further discusses the DPC hose order arrangement. Branham 

completed the DPC order on April 4 and shipped the hose directly to the Festus facility. Two of the hoses 

were put into service on June 15 at tank car station #3, and the third hose was put into service at station #1 

on July 26.17 The hose at station #3 that initiated the chlorine release failed after 59 days in service.18

CSB concludes that the 316L stainless-steel structural braid layer material of construction of the ruptured 

hose was inappropriate for the chlorine unloading operation at DPC Festus (see Section 4.3). Once the 

hose was put into service at tank car station #3, atmospheric moisture—in combination with permeating 

 

16 Several other companies in the United States manufacture Teflon-lined chlorine transfer hose with Hastelloy C 

braid. 

17 Visual inspection and X-ray fluorescence (XRF) testing confirmed that the two intact hoses from the March 18 

order were constructed of Hastelloy C (see Section 5.1.4). 

18 DPC typically keeps chlorine transfer hoses in service for 24 months from date of fabrication. 
DPC Festus 05-30-03 

47 

chlorine molecules from the Teflon inner liner—caused the stainless-steel braid layer to corrode, lose 

structural integrity, and eventually fail. 

5.1.2 Hose Identification 

Hastelloy C-276 and 316L stainless-steel structural braiding appear to be identical (see Figure 24). CSB 

investigators believe that the inability to visually distinguish these two structural braid layer alloys 

facilitated installation of the incorrect hose at DPC Festus. In fact, throughout the hose supply chain, 

there was no adequate mechanism (e.g., color-coding, stenciling, or stamping) to help identify similar 

looking hoses. 

Figure 24. Identical appearance of HastelloyC-276 and 316L stainless-steel structural braiding. 

5.1.3 Opportunities for Error in Supply Chain 

CSB investigators examined DPC hose practices, and also visited both Branham Corporation and CraneResistoflex to observe quality assurance (QA) and the manufacturing process for various types of hoses. 

CSB ruled out the possibility of a mixup at DPC Festus because the facility did not use any other hose 

assemblies with dimensions similar to the chlorine transfer hose (1 inch, 11 feet). 
DPC Festus 05-30-03 

48 

From the site visits and review of documentation, CSB investigators identified the following 

opportunities for error because of the inability to visually differentiate the two braid materials: 

• The paper tag labeling system used in the supply chain is not sufficient to prevent human 

error in positively identifying braid materials at receiving, fabricating, and shipping. If the 

tag of a hose within the Hastelloy bin is missing, mislabeled, or illegible, the hose could be 

assumed to be of Hastelloy braid construction. 

• Shipping areas in the supply chain contain various orders. Hastelloy C-276 and 316L 

stainless-steel braided hose could potentially be interchanged during packaging and the 

wrong material shipped to the customer. 

• Neither Crane-Resistoflex nor Branham conducts positive materials identification (PMI) 

testing of CTH shipments. (The North Carolina headquarters of Crane-Resistoflex performs 

PMI on bulk chlorine transfer hose as rolls are accepted into stock. However, no PMI is 

performed on chlorine transfer hose at the time of shipment to external fabricators or other 

customers.) 

Furthermore, CSB investigators found that Branham shipping documents indicated that the ruptured hose 

was constructed of Hastelloy braid when it was actually constructed of stainless-steel. Investigators also 

determined that Branham relied on visual verification and had no QA testing mechanisms prior to 

shipment to ensure that it supplied the correct hose to the customer. These findings lead CSB to conclude 

that Branham sent the incorrect hose to DPC. 

Crane-Resistoflex—which has several QA processes to aid in proper hose identification—is one of the 

manufacturers that supplies 316L stainless-steel structural braid hose to Branham. Although CSB 
DPC Festus 05-30-03 

49 

investigators were unable to determine exactly where in the supply chain the hose mixup occurred, they 

believe that it is unlikely that the error occurred at Crane-Resistoflex. 

5.1.4 Positive Materials Identification 

PMI is a chemical analysis that verifies the percentage of metals (e.g., iron, nickel) in various alloys, such 

as stainless-steel and Hastelloy. It is particularly useful in differentiating metallic parts of process 

components. Although PMI may not be a viable option on all types of chlorine transfer hose because of 

varying outer materials of construction, it is appropriate for the type of hose used at DPC for chlorine 

transfer. A PMI program can be used to verify critical part components as a final check prior to shipping 

and receiving, and may prevent errors from material mixups throughout the supply chain. 

CSB obtained samples of Teflon-lined hose with both Hastelloy C and stainless-steel braidings and 

contracted with a third party to analyze the samples via XRF nondestructive testing, a commonly used 

PMI test method. The analysis demonstrated that PMI testing would have differentiated Hastelloy C-276 

braid from 316L stainless steel. 

DPC relied on visual inspection and shipping documentation19 to confirm that the chlorine transfer hose 

met its specifications. The documentation received from Branham with the order containing the incorrect 

hose indicated that all three hoses were Teflon-lined with structural braiding of Hastelloy C-276. PMI (or 

some other QA mechanism) could have been performed on CTH shipments upon receipt from Branham 

or prior to installation. 

Thus, CSB concludes that DPC had no procedure in place to verify that the chlorine transfer hose was 

constructed of the correct material prior to placing it into hazardous materials service. 

 

19 Documentation includes the hose pressure test certification, work order with bill of materials, invoice, and 

shipping certification. 
DPC Festus 05-30-03 

50 

5.2 Mechanical Integrity 

A mechanical integrity (MI) program should ensure that critical process equipment and components are 

designed, fabricated, installed, inspected, tested, and maintained in a manner that preserves the originally 

intended integrity of the equipment. Furthermore, management should provide adequate oversight to 

ensure that only trained and qualified personnel carry out these activities. DPC is required to have an MI 

program because it stores and handles chlorine above the OSHA PSM and EPA RMP threshold quantities 

(as discussed in Section 1.3). 

The MI program for the Festus facility was based on dry chlorine service requirements. The materials of 

construction were appropriate for dry chlorine and were expected to provide years of service if the 

repackaging piping system was kept free of moisture. 

CSB reviewed the MI program at DPC for inspection, testing, and maintenance frequencies specific to 

several critical components of the chlorine repackaging system. Appendix C presents these frequency 

data. 

DPC Festus did routinely inspect, test, and maintain critical components of the chlorine repackaging 

system. However, these tasks were not performed to the level necessary to identify or prevent corrosion. 

CSB investigators identified the following deficiencies in the MI program: 

• Inadequate supervision (management oversight) of inspection and test personnel. 

• Insufficient training of packagers on the catastrophic potential of corrosion-induced system 

failure. Such training could have emphasized the importance of keeping the system free of 

moisture. 
DPC Festus 05-30-03 

51 

• Inadequate auditing of operating procedures to ensure positive verification of ESD valve 

closures. 

• Insufficient detail in procedures to ensure adequate inspection. 

The MI program at DPC did not provide sufficient training on the causes and effects of moisture-induced 

corrosion in the chlorine repackaging system—training that could have heightened employee awareness 

to deteriorating equipment conditions. As described below, CSB investigators reviewed whether routine 

schedules for inspection and testing of critical components, such as the system piping and dryers, were 

sufficient to identify corrosion-related problems. 

5.2.1 Management Oversight 

Routine inspection, testing, and maintenance checks at DPC Festus were inadequate and poorly 

supervised. For example, one of the requirements in the chlorine system startup checklist (used daily) is 

to visually inspect the external surface of the chlorine transfer hose. DPC packagers should have 

inspected the subject hose on the day of the incident, prior to startup, and looked for visual or physical 

clues as to any potential problems. With appropriate training and supervision, they should have been able 

to identify external corrosion of the hose braid layer and to then follow a set procedure for reporting such 

observations. 

In July 2001, the DPC Festus operations manager resigned. Over the next 6 months, various DPC 

corporate personnel managed the site. During this transition, there were periods with no management 

supervision of day-to-day operations, including inspections. 

Although a new manager was hired and assigned day-to-day supervision responsibility in January 2002, 

he was inexperienced in chlorine repackaging operations. DPC provided some training on chlorine 

repackaging, but it was inadequate for his safety responsibilities and did not sufficiently cover the 
DPC Festus 05-30-03 

52 

importance of preventive maintenance and inspection. The new manager assumed that the packagers 

were performing their tasks properly because of their combined chlorine repackaging experience. 

5.2.2 Operator Training 

Although DPC provided training on elements of the MI program—such as inspection, testing, and 

maintenance—it focused on “how to and when to,” not on the consequences of a less-than-adequate 

inspection or warning signals of equipment failure. For example, CSB investigators believe that neither 

the supervisor nor the packagers fully understood the need to keep the repackaging system free of 

moisture or the potential impacts of not identifying and preventing corrosion. Corrosion problems within 

the pad air and unloading assemblies and other parts of the system (created by moisture-intrusion) were 

not addressed in a timely manner, which allowed the ESD valves to become clogged. 

The MI program at DPC did not provide sufficient training on the causes and effects of moisture-induced 

corrosion in the chlorine repackaging system—training that could have heightened employee awareness 

to deteriorating equipment conditions. 

5.2.3 Auditing of Inspection Procedures 

The review and update of MI program standard operating procedures is critical to ensure the optimal and 

safe performance of process equipment. DPC did not adequately audit its standard operating procedures. 

For example, though DPC tested operation of the ESD system daily by activating manual buttons, the 

testing procedures offered no assurance that the valves actually closed during shutdown at the end of the 

day or in an emergency because personnel did not verify the position indicators on the ESD valves 

(Figure 13). A thorough audit of standard operating procedures could have identified that additional steps 

were needed to positively verify closure of the ESD valves. 
DPC Festus 05-30-03 

53 

5.2.4 Auditing of Schedules 

DPC bought the Festus facility in August 1998. The chlorine repackaging system piping was replaced in 

June 1999 as part of the process upgrade. Since that time, however, the piping had not been measured for 

wall thickness, nor internally inspected. The DPC inspection and testing frequency for this piping is 

every 5 years; the next testing was scheduled for 2004. 

The Chlorine Institute (1998) provides recommendations and guidance for the regular inspection, testing, 

and maintenance of chlorine piping systems. The definition of “regular” is left up to the facility to 

determine based on individual site conditions. 

In dry chlorine service, corrosion should be anticipated because of the difficulty in isolating the system 

from moisture. Historical information and operating experience are good measures for selecting 

inspection and testing frequencies. MI program schedules should be routinely audited to ensure that their 

intervals are of adequate duration to identify and prevent process safety problems, such as corrosion, 

before there is a risk of system failure. The internal inspection of the piping system and valves at DPC 

Festus was not sufficient to identify corrosion problems. 

The ESD valves were not visually inspected or tested for ease of closure prior to the incident. The 

Chlorine Institute (1997) provides minimum guidelines for design and installation of ESD valves: 

“. . . such emergency systems must be regularly inspected for mechanical integrity.” The Center for 

Chemical Process Safety (CCPS, 1997) discusses emergency isolation of releases, design and operation of 

emergency ESD valves, and the need for routine inspection and testing. CCPS states: “Testing of 

isolation devices needs to be a complete functional check, which includes switch operation through 

actuation of the final control element (valve, pump, etc.) . . .” 

It is vital that critical process piping and equipment and safety systems, such as the ESD system, be 

included in a documented and audited MI program. Routine testing of the ESD valves to verify that they 
DPC Festus 05-30-03 

54 

are, in fact, closed after actuating the system—combined with periodic internal inspections—could have 

ensured that the valves would close on demand, and greatly lessened the quantity and duration of the 

chlorine release. 

5.2.5 Source of Corrosion 

DPC Festus packagers were not fully aware of the importance of keeping the system free of moisture or 

the consequences of failing to do so. This lack of awareness played a critical role in events leading up to 

the incident on August 14. In dry chlorine service, even very small amounts of moisture entering the 

chlorine piping system, such as humidity, can create significant corrosion problems within carbon steel 

piping (Roberge, 2000). 

As discussed in Section 4.5, CSB concludes that the valves did not close because of the buildup of 

corrosion products around ESD valve balls. Inspection of the repackaging system revealed evidence of 

corrosion within the pad air supply and tank car unloading assemblies, as well as in parts of the facility 

liquid and pad air carbon steel piping (Figure 25).20 These corrosion products readily migrated to the 

valves. 

CSB identified three possible sources of the corrosion-producing moisture (see Appendix A for details): 

• Pad air used to provide pressure for the transfer of liquid chlorine from the tank car 

• Ambient moisture intrusion into the piping 

• Wet chlorine in the tank car. 

 

20 The unloading assembly in use at tank car station #3 at the time of the incident and a second set of assemblies not 

in use were inspected; both exhibited corrosion. 
DPC Festus 05-30-03 

55 

Figure 25. Corrosion buildup in chlorine repackaging piping system. 

The DPC Festus MI program was not successful in preventing corrosion within the chlorine repackaging 

system because it did not adequately address related supervision, procedures, and inspection. 

5.3 Emergency Management 

Emergency management is the process of preparing for, mitigating, responding to, and recovering from 

an emergency (FEMA, 2003). Facilities that handle chemicals—and the communities in which they are 

located—are required by Federal law to address all aspects of emergency management through the 

development of emergency response plans. 
DPC Festus 05-30-03 

56 

5.3.1 Facility Requirements 

Facility emergency response plans primarily address requirements of the following Federal laws and 

regulations:21

• Emergency Planning and Community Right-To-Know Act (EPCRA; Title III of the 

Superfund Amendments and Reauthorization Act [SARA] of 1986). 

• EPA Risk Management Program (RMP). 

• OSHA Process Safety Management (PSM) Standard.22

The basic requirements of these laws and regulations are similar. Because DPC stores and handles 

chlorine at quantities that exceed threshold values set by EPCRA, RMP, and PSM, it is required to 

comply with the emergency planning and response elements of these regulations. Appendix D provides 

information on procedures for community notification and emergency response, employee training and 

drills, and coordination of activities. 

5.3.2 DPC Emergency Response Plan 

In reviewing the DPC emergency response plan, CSB investigators identified the following deficiencies: 

• Lack of clear guidelines and mechanisms for community notification (e.g., community sirens, 

alert network). 

• Inadequate designation of responsibilities of facility emergency response personnel. 

 

21 Various other laws and regulations have emergency management requirements, such as The Oil Pollution Act 

Spill Prevention, Control and Countermeasures (SPCC), the EPA Oil Pollution Prevention Regulation, the OSHA 

Emergency Action Plan Regulation and Hazardous Waste Operations and Emergency Response (HAZWOPER), and 

the Resource Conservation and Recovery Act (RCRA) Contingency Planning Requirements. 22The PSM Standard references the OSHA Emergency Action Plan (1910.38) and HAZWOPER (1910.120) with 

regard to emergency response plans. 
DPC Festus 05-30-03 

57 

• Lack of clear guidelines to determine if an incident requires facility response or offsite 

community responders (emergency response assessment). 

• Inadequate procedures for training and drills. 

• Inaccessible location of emergency response equipment. 

• Lack of clear guidelines for post-incident remediation (i.e., planning, handling, and disposing 

of hazardous materials). 

These deficiencies resulted in DPC’s inadequate preparation for a large uncontrolled release. CSB does 

not question the DPC decision to evacuate the facility and request community emergency response 

assistance. The focus of the CSB review of the emergency response plan is on evaluating DPC 

emergency management to identify areas of improvement in terms of preventing exposures and reducing 

the mitigation time of future releases. 

5.3.2.1 Community Notification 

The DPC emergency response plan did not contain adequate guidelines or mechanisms to ensure prompt 

community notification of an incident. Although local authorities have the primary responsibility for 

notifying the public of an emergency, the company shares responsibility for notifying and educating 

neighboring residents and businesses in advance on how to respond to an emergency. The plan did not 

clearly designate an employee or establish a system (e.g., sirens, alert network) to notify neighboring 

businesses and residents. 

One of the critical elements of the EPA RMP is to ensure that a facility’s emergency response plan 

includes procedures for informing the public and local authorities of a release. “This must include the 

groups and individuals that will be contacted and why, the means by which they will be contacted, the 

time frame for notification, and the information that will be provided” (USEPA, 2000a). 
DPC Festus 05-30-03 

58 

Although DPC had procedures and effectively notified local agencies and emergency response personnel 

of the release, it did not adequately inform the public. The emergency response plan contained contact 

numbers for the local emergency planning committee (LEPC), nearby businesses, and neighbors—

including the construction and tire retreading company, the mobile home park, and the owner of an 

adjacent farm—but it did not assign responsibility for notification to any specific personnel. Emergency 

responders went door-to-door at the Blue Fountain mobile home park and in other nearby residential areas 

to notify residents of the release; this took over an hour. No procedures for evacuation or shelter-in-place 

had been given in advance to residents or businesses. 

Another incident at DPC Festus, in January 1999, demonstrated the need for improved community 

notification. In that incident, a 1-ton container of chlorine was dropped as it was being loaded onto a 

truck (Figure 26). The fall damaged the container valves and released 1,500 pounds of chlorine. Twentytwo residents and two DPC employees sought medical evaluation due to exposure; one person was 

admitted and released the following day. Several residents and community officials interviewed by CSB 

in the course of the 2002 investigation indicated that DPC had committed to update its community 

notification procedures and implement a notification system as result of the 1999 incident. However, 

DPC did not follow through on this commitment. 

Figure 26. Truck loading station at DPC Festus. 
DPC Festus 05-30-03 

59 

In both incidents, the lack of an adequate community notification system and clear guidelines for its 

implementation contributed to impact or injury to the public. The Chlorine Institute (2000a) states that 

“internal and external communications are critical during an emergency.” The Institute recommends the 

use of siren systems, automatic telephone alert systems, and radio and TV media. To facilitate 

implementation, it further recommends that local authorities be involved in developing community 

notification procedures. (Section 5.3.4.1 discusses community requirements regarding notification.) 

Once a community notification system is in place, it must be tested and updated on a regular basis, and 

the public should be educated on how to properly respond to an emergency. However, community 

notification is no substitute for prevention of the release in the first place. 

5.3.2.2 Designation of Responsibilities 

The DPC emergency response plan did not clearly specify the responsibilities of response team members 

during a release. The Chlorine Institute (2000a) recommends that any emergency response plan include 

the following: 

• Types of emergencies to which the team will respond. 

• Role of each response team member during an emergency (e.g., gathering response 

equipment, release assessment, release control, communications, first aid). 

• Chain of command. 

• Community notification procedures. 

An emergency response plan that clearly designated responsibilities would have ensured that DPC was 

better prepared for managing a large uncontrolled release. 
DPC Festus 05-30-03 

60 

5.3.2.3 Emergency Response Assessment 

Although the DPC Festus facility evacuation procedures contained instructions for employee action 

during a release, they did not provide clear guidance on when facility emergency response personnel 

respond to a release or when offsite community HAZMAT response is required. This lack of guidance 

explains the indecision among facility personnel responsible for assessing emergency response options. 

For example, the DPC Festus emergency response plan states: “. . . for large releases, the company 

emergency response team, or an off-site HAZMAT team would be contacted for assistance. A large 

release is defined as an uncontrolled release.” 

The plan goes on to define both an “uncontrolled” and a “controlled or incidental” release, but it does not 

provide any guidance on conditions (e.g., weather, quantity of release, availability of response team 

members) under which an uncontrolled release requires offsite community response. More definitive 

emergency response plan guidelines would have helped DPC personnel better assess response 

capabilities. 

“One of the most important issues in an emergency response plan is deciding which response actions will 

be assigned to employees and which will be handled by offsite personnel” (USEPA, 2000a). The DPC 

emergency response plan contained no guidance to help personnel assess the situation and respond 

appropriately. 

5.3.2.4 Training, Audits, and Drills 

The DPC emergency response plan did not contain timetables or schedules for either initial or annual 

employee refresher training in accordance with HAZWOPER requirements. The plan had no built-in 

audit procedures. Furthermore, it made no provisions for drilling emergency response personnel on 

various levels of response. Interviews with facility personnel reiterated that DPC did not conduct 

training, audits, or drills on a regular basis. 
DPC Festus 05-30-03 

61 

The Chlorine Institute (2000a) recommends that emergency response plan training include the following 

elements: 

• Timetables or schedules for training, including start date, number of sessions held, and target 

completion date. 

• Yearly refresher training. 

• Documentation, including a list of personnel trained and date training was completed. 

Audits and drills are effective in determining the adequacy of emergency response plan training. Audits 

provide a thorough assessment of employee knowledge of responsibilities, communication needs, and 

equipment. Drills test the actual mechanics of the plan, and employee reactions and effectiveness in 

implementing the plan (Chlorine Institute, 2000a). Tabletop drills provide a low-stress opportunity to 

discuss emergency response issues; functional drills simulate an actual emergency; and full-scale drills 

test the response of the entire community. 

DPC Festus was not prepared for a major uncontrolled release because of inadequate auditing of 

emergency response team capabilities and the lack of periodic, scheduled drills. Essential equipment was 

inaccessible. The DPC emergency response plan should have contained guidelines on auditing and 

drilling for releases/emergencies with varying degrees of response, and incorporated lessons learned from 

audits and drills. It should be reviewed annually, whenever the facility is modified, and whenever there 

are personnel or organizational changes. 

5.3.2.5 Emergency Response Equipment 

The DPC emergency response plan did not have clear guidelines on emergency equipment testing and 

inspection. Also omitted were guidelines for proper storage and accessibility of response equipment. The 

absence of these plan elements contributed to DPC being unprepared for a large uncontrolled release. 
DPC Festus 05-30-03 

62 

As discussed in Section 3.2.4, emergency response equipment was not readily accessible during the 

release. The DPC emergency response plan states: “Designated exiting employees shall collect and take 

SCBA and other appropriate emergency response equipment to the staging area.” This equipment was 

stored in the repackaging building, which was an appropriate location for responding to a minor release. 

However, because the equipment was not adequately maintained or organized, the packagers (who also 

served on the facility emergency response team) were unable to gather it upon exiting the building and the 

facility. The building rapidly filled with chlorine gas because of its proximity to the release. One 

alternative could have been to store additional equipment at another location, possibly offsite. 

The Chlorine Institute (2001) states: “ All personnel required to wear respiratory protection equipment 

(such as SCBAs) should be trained and tested annually on its proper use.” The Institute recommends that 

respiratory protection equipment be inspected monthly and after each use. Furthermore, the OSHA 

Respiratory Protection Standard (1910.134) requires monthly inspections and annual refresher fit testing 

of respirators used for emergency response. 

The EPA RMP guidance document specifies that an emergency response plan should include the 

following written guidelines on equipment testing and inspection (USEPA, 2000b): 

• How and when to properly use the equipment 

• How and when to conduct routine equipment maintenance 

• How and when to inspect and test equipment for readiness. 

The DPC emergency response plan contained no documentation, schedules, or procedures to indicate that 

these regulatory requirements were fulfilled. 
DPC Festus 05-30-03 

63 

5.3.2.6 Post-Incident Remediation 

Section 3.2.8 describes cleanup activities after the release was shut off. Three DPC employees were 

exposed to chlorine as they attempted to remediate an accumulation of chlorine hydrate that had formed 

next to the tank car, underneath the ruptured hose. The DPC emergency response plan included no 

guidelines for planning post-incident cleanup of hazardous materials. 

DPC operators attempted to neutralize the chlorine with calcium carbonate (limestone). However, the 

operators wore level C PPE, which was inadequate for the job; and they were exposed to the chlorine. 

The OSHA HAZWOPER regulation requires proper planning to address the following elements prior to 

beginning post-incident remediation: 

• Evaluation of hazards 

• Selection of proper PPE 

• Understanding of potential outcomes 

• Requirements for additional resources. 

5.3.2.7 Other Issues 

Under EPCRA, RMP, and PSM, facilities are not required to submit emergency plans to local authorities. 

However, EPCRA and RMP do require the facility to coordinate with and provide information to local 

authorities so that the community is prepared to handle accidental hazardous chemical releases. An 

emergency coordinator must be designated to work with local authorities on chemical emergency 

preparedness. The EPA RMP guidance document recommends that the facility also coordinate 

emergency response training and drills with local planning authorities, and offer them a copy of the plan. 
DPC Festus 05-30-03 

64 

Coordination between local emergency planning and response entities and DPC was insufficient to ensure 

that the emergency plan would provide for timely community notification and mitigation of the release. 

5.3.3 Community Emergency Response Requirements 

In 1986, Congress passed the Superfund Amendments and Reauthorization Act (SARA). It was designed 

to establish a national baseline for planning, response, management, and training for chemical 

emergencies. Title III of this legislation, EPCRA, requires the establishment of both state and local LEPC 

groups. 

The community right-to-know aspect of SARA created new rights for members of the public and local 

governments to increase their knowledge and access to information on hazardous chemicals from 

neighboring facilities. The LEPC is responsible for developing an emergency response plan that includes: 

• Local facilities and transportation routes where hazardous materials are present. 

• Procedures for immediate response in case of an accident, including a community-wide 

evacuation plan. 

• Procedures for community notification. 

• Names of response coordinators at local facilities. 

• Procedures for testing emergency response. 

The plan is reviewed by the state and publicized throughout the community. The LEPC is required to 

review, test, and update the plan each year. 

The Jefferson County LEPC works with the County Emergency Management Agency (EMA) in planning 

for emergencies The EMA develops the community emergency response plan. The LEPC, which 
DPC Festus 05-30-03 

65 

includes various local authorities (e.g., fire, police, HAZMAT) and facilities, is scheduled to meet six 

times a year. The DPC operations manager is a member of the LEPC. 

5.3.4 Community Emergency Response Plan 

CSB investigators identified the following deficiencies in the Jefferson County emergency response plan: 

• The plan had not been updated since 1996. 

• Its hazardous materials incident component was too general. It should have included, for 

example, specific procedures for high public consequence HAZMAT events—such as a large 

chlorine release—that may require community notification, community evacuation, or 

shelter-in-place. 

• It did not include methods and schedules for testing with all participating local authorities 

(e.g., Jefferson County EMA; LEPC; Festus, Crystal City, and Jefferson County police and 

fire departments; HAZMAT unit; Jefferson Memorial Hospital; ambulance services). 

• It had not been tested for such potential responses as public evacuation or shelter-in-place. 

Response to the August 14 incident highlighted the need for evaluation and revision of the community 

emergency response plan—which may include review of actual responses and incorporation of lessons 

learned, simulation drills/exercises, and regular collection of new data. Drills and exercises could have 

revealed or clarified planning and training weaknesses, resource needs, roles and responsibilities, and 

coordination among all responsible local authorities (e.g., 9-1-1 dispatch, police, fire, and HAZMAT), 

thus improving the overall performance of all parties (see Appendix D). Effective emergency 

preparedness requires periodic review and evaluation of the community emergency response plan at the 

community level (National Response Team [NRT], 2001). 
DPC Festus 05-30-03 

66 

5.3.4.1 Community Notification 

Local authorities have the primary responsibility to notify the public of an emergency. In this incident, 

the community notification system was inadequate. Both local authorities and DPC should have worked 

together during development of the community emergency response plan to establish a warning system. 

As discussed in Section 3.2.6, emergency personnel drove through neighborhoods and went door-to-door 

to notify people to evacuate, which extended the period of public exposure. 

The community emergency response plan calls for evacuation and shelter-in-place information to be 

disseminated via radio and television. However, community sirens or alert networks that immediately 

notify the exposed public are a better alternative. Radio and television can be used to provide followup 

information. 

The NRT Hazardous Materials Emergency Planning Guide recommends that the community plan contain 

precise information on how sirens or other signals will be used to alert the public. This should include 

information on what the different signals mean, how to coordinate the use of sirens, and the geographic 

area covered by each siren. If possible, a backup procedure should be identified. Further, the guide states 

that, though “a siren alerts those who hear it, an emergency broadcast is necessary to provide detailed 

information about the emergency and what people should do” (NRT, 2001). 

5.3.4.2 Community Emergency Preparedness 

The August 14 release at DPC continued for nearly 3 hours. Better preparedness among local emergency 

planning and response authorities could have reduced the overall response and mitigation time; however, 

it is no substitute for prevention of the release itself through preventive maintenance, testing, and 

inspection to ensure that the ESD system effectively shuts off all releases. 

NRT (2001) recommends that the emergency response plan identify all local agencies that make up the 

community’s existing response preparedness network. It states: 
DPC Festus 05-30-03 

67 

. . . each (agency’s) function (e.g., direction and control, communications, evacuation, release 

shut off) should be clearly marked with a tab so that it can be located quickly . . . each response 

function usually includes several response activities. Some communities prepare a matrix that 

lists all response agencies down the left side of the page and all response activities across the top 

of the page. Planners can then easily determine which response activities need interagency 

coordination and which, if any, activities are not adequately provided for in the plan. 

As noted below, CSB investigators determined that the overall response and release mitigation time could 

have been improved: 

• It took 15 minutes for the HAZMAT duty officer to page the full team to respond to the 

incident. HAZMAT team procedures require the duty officer, once notified, to first contact 

the incident commander to assess if a full team response is necessary. Alternatively, for large 

chemical releases (as determined by the incident commander), 9-1-1 could inform the duty 

officer that a full team mobilization is necessary rather than having him or her take additional 

time to contact the incident commander. 

• The HAZMAT duty officer and several other team members had to request permission to 

leave their jobs to respond to the incident, which caused some delay in response. Procedures 

could be developed to facilitate immediate release of volunteer HAZMAT team members 

upon notification of an emergency. 

• The HAZMAT duty officer was delayed in traffic for 15 minutes en route to the incident. He 

said during an interview that he was not authorized to place markings, lights, or sirens on his 

personal vehicle when responding to an emergency; without such, he was unable to use an 

open shoulder lane to bypass highway construction. 
DPC Festus 05-30-03 

68 

• The HAZMAT truck was redirected from the north command post to the south post, where 

State, County, and local authorities were coordinating their response. Having two command 

posts increased the potential for breakdowns in communication. 

These specific deficiencies indicate less-than-adequate community planning, training, and drills. Better 

coordination among all planning and response authorities would improve emergency communication, 

allocation of resources, and response and mitigation time. Regular updates of the community emergency 

response plan—to incorporate lessons-learned from training, drills, and actual incidents—are also critical 

to effective emergency response. 

ATSDR and the Federal Emergency Management Agency (FEMA) offer additional guidance specifically 

designed to assist communities develop evidence-based assumptions in preparing for hazardous materials 

emergencies and disasters. 

5.4 The Chlorine Institute Recommended Practices 

DPC Enterprises is a member of The Chlorine Institute, Inc., which is the chief source of industry best 

practices for chlorine repackagers. The specific Chlorine Institute publications that pertain to this 

incident are: 

• Pamphlet 6, Piping Systems for Dry Chlorine (1998) 

- Contains the majority of recommended practices dealing with the metallurgy of piping 

and hoses in chlorine transfer operations. Although this guidance provides details for 

piping in dry chlorine service, as well as specifications for transfer hoses, it does not 

discuss the pathways for moisture intrusion, consequences of moisture-induced corrosion, 

or specifications for piping systems that are susceptible to such corrosion. 
DPC Festus 05-30-03 

69 

• Pamphlet 57, Emergency Shut-Off Systems for Bulk Transfer of Chlorine (1997) 

- Addresses the design and installation of emergency shutoff systems. However, it does 

not provide guidance on the procedures for testing and inspection to ensure continued 

operation of the shutoff valves, especially with regard to potential moisture-induced 

corrosion. 

• Pamphlet 64, Emergency Response Plans for Chlorine Facilities (2000a) 

- Addresses the full range of releases, from minor to catastrophic. The Institute refers to 

these releases as “major emergencies, outside the overall facility—requiring outside 

help.” Although this guidance calls for the involvement of outside responders for 

emergency control, it does not discuss communication between a facility and the local 

responders and emergency planning authorities to ensure that adequate resources are in 

place for major emergencies. 

5.5 NACD Responsible Distribution Process 

DPC Enterprises is part of DX Distribution Group, a network of distribution and storage companies. The 

DX Group is a member of NACD. As a condition of membership, companies commit to the NACD 

Responsible Distribution Process(RDP), which requires continuous improvement in protecting health, 

safety, and the environment, and includes the Code of Management Practice. The code covers 12 

elements, including risk management, carrier selection, handling and storage, and continuous 

improvement. Article IV, Handling and Storage, specifies that the company have a program to promote 

facility integrity and provisions for control of processes during emergencies. 

A key requirement of RDP and a condition of membership in NACD is third-party verification of member 

RDP policies and procedures. Although DPC Enterprises is a part of the DX Distribution Group network, 
DPC Festus 05-30-03 

70 

NACD did not considered the Festus facility to be a member and it did not have to meet RDP 

membership requirements. Based on membership information provided by NACD, only one DX 

Distribution Group company (DXI Distributors, Inc.) was an NACD member. 
DPC Festus 05-30-03 

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6.0 Root and Contributing Causes 

6.1 Root Causes 

1. The DPC quality assurance (QA) management system did not have adequate provisions to 

ensure that chlorine transfer hoses (CTH) met required specifications prior to installation 

and use.

Hastelloy C-276 and 316L stainless-steel structural braiding are identical in appearance. The 

inability to visually distinguish the two materials offers an explanation for installation of the 

inappropriate hose at DPC Festus. DPC relied on information from the supplier to verify that the 

chlorine transfer hose met required specifications; the lack of an internal QA management 

system, including verification of braid material, allowed the incorrect hose to be installed and left 

in operation until it failed. 

2. Branham Corporation, the CTH fabricator/distributor, did not have a QA management 

system to ensure that fabricated hose actually complied with customer specifications or that 

its own certification of materials specifications were correct. 

Branham did not have a system to ensure that it fabricated and shipped the exact hose specified 

by the customer (DPC Festus) because of the absence of PMI testing and the inability to validate 

its own certification and shipping documents. 

3. The DPC testing and inspection program did not include procedures to ensure that the 

process emergency shutdown (ESD) system would operate as designed. 

DPC procedures for daily testing of the ESD system were not specific. For example, it was not 

explicitly stated that the system must be tested from the activating device (button or detector) 
DPC Festus 05-30-03 

72 

through to verification that the valves actually closed. Inadequate testing and inspection of the 

ESD system probably led to undetected failures of the system valves at tank car station #3 prior to 

the August 14, 2002, failure. 

6.2 Contributing Causes 

1. The hose identification system of CTH manufacturers is inadequate to provide continuous 

positive identification of similar-looking structural braiding materials of construction, such 

as Hastelloy C and stainless steel. 

2. The DPC mechanical integrity (MI) program failed to detect corrosion in the chlorine 

transfer and pad air systems before it caused operational and safety problems. 

Wet chlorine caused excessive corrosion of the chlorine unloading piping and pad air piping 

systems, which prevented the ESD valves from closing properly. Potential sources of water 

include: 

• Atmospheric moisture from inadequate capping of hoses and tank car piping assemblies. 

• Moisture from the pad air supply system. 

3. The community notification system was inefficient, which resulted in additional exposure to 

neighboring residents and businesses. 

Because of the catastrophic nature of the chlorine release, personnel evacuated the facility 

immediately without simultaneously notifying neighboring businesses and residents. 
DPC Festus 05-30-03 

73 

4. DPC emergency preparedness planning was deficient. 

Lack of clear guidelines and mechanisms for community notification (e.g., community sirens, 

alert network); inadequate designation of responsibilities of facility emergency response 

personnel; lack of clear guidelines to determine if an incident requires facility response or offsite 

community response; inadequate training and drills; inaccessible location of emergency response 

equipment; and lack of clear guidelines for post-incident remediation resulted in DPC’s 

inadequate preparedness for a large uncontrolled release. 

5. Jefferson County community emergency preparedness planning was inadequate for an 

incident of this magnitude. 

Better planning that involved all local emergency response and planning authorities could have 

improved the overall response and mitigation time on August 14. For example, members of the 

all-volunteer Jefferson County HAZMAT response team arrived on-scene over a 0.5- to 1.25- 

hour period, and the setup of two separate command posts along the highway caused confusion. 
DPC Festus 05-30-03 

74 

7.0 Recommendations 

DPC Enterprises L.P., Festus Site 

1. Revise the mechanical integrity program: 

• Develop and implement a quality assurance management system, such as positive 

materials identification, to confirm that chlorine transfer hoses (CTH) are of the 

appropriate materials of construction. (2002-04-I-MO-R1) 

• Implement procedures and practices to ensure the emergency shutdown (ESD) system 

operates properly. Include procedures to verify that the ESD valves will close to shut 

down the flow of chlorine. (2002-04-I-MO-R2) 

• Revise the preventive maintenance and inspection program for the chlorine transfer 

system to address moisture-related corrosion. Evaluate and correct any problems 

associated with corrosion that could potentially lead to chlorine transfer and safety 

system failure. (2002-04-I-MO-R3) 

• Require periodic inspection of the above critical safety systems by the operations or 

facility manager. (2002-04-I-MO-R4) 

2. Revise the Emergency Response Plan: 

• Develop procedures to clearly designate the roles and responsibilities of facility 

emergency response personnel, including post-incident remediation. (2002-04-I-MO-R5) 

• Develop and implement a timetable for drills to test emergency response personnel on 

various levels of response, including a large uncontrolled release that could affect the 
DPC Festus 05-30-03 

75 

public. Coordinate these drills with local emergency response authorities. Provide a 

copy of the revised Emergency Response Plan to the local emergency planning 

committee, and review the plan with the committee and the local fire department. Work 

with these authorities to implement an improved community emergency notification 

system. (2002-04-I-MO-R6) 

• Improve accessibility of equipment required for emergency response, considering likely 

response scenarios. (2002-04-I-MO-R7) 

DX Distribution Group (corporate owner of DPC Enterprises, L.P.) 

1. In light of the findings of this report, conduct periodic audits of the safety management systems 

involved in this incident, such as mechanical integrity, emergency response, and material quality 

assurance. Ensure that the audit recommendations are tracked and implemented. Share findings 

and recommendations with the work force at your repackaging facilities. (2002-04-I-MO-R8) 

2. To improve supervision of day-to-day operations, revise your corporate safety managementtraining program on chlorine repackaging operations. Emphasize safety critical systems, 

including verification of safety system performance. (2002-04-I-MO-R9) 

3. Communicate the findings and recommendations of this report to all DPC facilities. (2002-04-IMO-R10) 

Branham Corporation 

Implement a materials verification procedure to improve quality assurance during chlorine transfer hose 

fabrication and shipment, such that hoses shipped to customers are readily identifiable and meet required 

specifications. (2002-04-I-MO-R11) 
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76 

Jefferson County Emergency Management Agency (EMA) 

1. Work with DPC to implement a community notification system that will immediately alert 

neighboring residents and businesses of a chemical release. (2002-04-I-MO-R12) 

2. Work with DPC, local emergency planning and response authorities in Jefferson and adjacent 

counties, the City of Festus, and Crystal City to improve overall response and mitigation time. 

(2002-04-I-MO-R13) 

3. Communicate the findings and recommendations of this report to your membership. (2002-04-IMO-R14) 

Missouri State Emergency Response Commission 

Communicate the findings and recommendations of this report to local emergency planning committees 

(LEPC), emergency management agencies (EMA), and local fire departments. (2002-04-I-MO-R15) 

Missouri Department of Natural Resources (MDNR) 

In collaboration with appropriate agencies, hold a community meeting in Festus, Missouri, to hear 

concerns raised by local citizens affected by the DPC incident and to respond to issues raised by the 

community. (2002-04-I-MO-R16) 

Agency for Toxic Substances and Disease Registry (ATSDR) 

Work with State and local agencies to address concerns about the long-term health effects of the chlorine 

release in Festus, Missouri, and communicate your findings to the community. (2002-04-I-MO-R17) 
DPC Festus 05-30-03 

77 

The Chlorine Institute, Inc. 

1. Work with the Association of Hose and Accessories Distributors (NAHAD) and chlorine hose 

manufacturers, such as Crane-Resistoflex, to develop and implement a recommended practice 

requiring continuous positive identification (e.g., coding, stenciling, stamping) throughout the 

supply chain, from manufacturing to the end user of the product. (2002-04-I-MO-R18) 

2. Develop recommended practices to address moisture in dry chlorine piping systems. Include 

information on suggested material specifications, prevention and corrective measures, and 

adverse consequences (particularly for emergency shutdown [ESD] systems). (2002-04-I-MOR19) 

3. Develop recommended practices for testing, inspection, and preventative maintenance of ESD 

systems for bulk transfer of chlorine. (2002-04-I-MO-R20) 

4. Communicate the findings and recommendations of this report to your membership. (2002-04-IMO-R21) 

National Association of Hose and Accessories Distributors (NAHAD) 

1. Work with The Chlorine Institute and chlorine hose manufacturers, such as Crane-Resistoflex, to 

develop and implement a recommended practice requiring continuous positive identification (e.g., 

coding, stenciling, stamping) throughout the supply chain, from manufacturing to the end user of 

the product. (2002-04-1-MO-R22) 

2. Communicate the findings and recommendations of this report to your membership. (2002-04-1-

MO-R23) 
DPC Festus 05-30-03 

78 

National Association of Chemical Distributors (NACD) 

Communicate the findings and recommendations of this report to your membership. (2002-04-I-MOR24) 

 

By the 

U.S. Chemical Safety and Hazard Investigation Board 

Carolyn W. Merritt 

 Chair 

 John S. Bresland 

 Member 

 Gerald V. Poje, Ph.D. 

 Member 

 Isadore Rosenthal, Ph.D. 

 Member 

 Andrea Kidd Taylor, Dr. P.H. 

 Member 

May 1, 2003 
DPC Festus 05-30-03 

79 

8.0 References 

American Society for Metals, 1990. ASM Handbook, Volume 1, 10th edition, April 1990. 

Center for Chemical Process Safety (CCPS), 1997. Guidelines for Post release Mitigation Technology in 

the Chemical Process Industry, American Institute of Chemical Engineers (AIChE). 

CCPS, 1995. Guidelines for Technical Planning for On-Site Emergencies, AIChE. 

CCPS, 1993. Guidelines for Safe Automation of Chemical Processes, AIChE. 

Ellenhorn, M. J., and D. G. Barceloux, 1988. Medical Toxicology: Diagnosis and Treatment of Human 

Poisoning, Elsevier Science Publishing Co., Inc. 

Engineering Evaluations Inspections Inc. (EEI Inc.), 2003. A Fact-Based Report Describing the Events 

Surrounding a Chlorine Release on August 14, 2002, at the Festus, Missouri, DPC Facility. 

Federal Emergency Management Agency (FEMA), 2003. Emergency Management Guide for Business & 

Industry, www.fema.gov. 

Missouri Department of Natural Resources, 2002. Environmental Emergency Response Report, Spill 

Incident #020814-1000-RDS. 

National Institute of Occupational Safety and Health (NIOSH), 2003. “Chlorine,” NIOSH Pocket Guide 

to Chemical Hazards, www.cdc.gov/niosh/npg/npgd0115.html. 

National Response Team (NRT), 2001. Hazardous Materials Emergency Planning Guide, NRT-1. 

National Transportation Safety Board (NTSB), 2002. Hazardous Materials Release From Railroad Tank 

Car With Subsequent Fire at Riverview, Michigan July 14, 2001, PB2002-917002. 
DPC Festus 05-30-03 

80 

Roberge, Pierre R., 2000. Handbook of Corrosion Engineering, McGraw Hill. 

The Chlorine Institute, Inc., 2003. Ferric Chloride in Chlorine Piping Systems From the Reaction 

Between Wet Chlorine and Steel, Technical Sheet #16, April 2003. 

The Chlorine Institute, Inc., 2002. Dry Chlorine: Definitions and Analytical Issues, Pamphlet 100, 

Edition 2, September 2002. 

The Chlorine Institute, Inc., 2001. Personal Protective Equipment for Chlor-Alkali Chemicals, Pamphlet 

65, Edition 4, November 2001. 

The Chlorine Institute, Inc., 2000a. Emergency Response Plans for Chlorine Facilities, Pamphlet 64, 

Edition 5, November 2000. 

The Chlorine Institute, Inc., 2000b. The Chlorine Manual, Pamphlet 1, Edition 6, March 2000. 

The Chlorine Institute, Inc., 1998. Piping Systems for Dry Chlorine, Pamphlet 6, Edition 14, December 

1998. 

The Chlorine Institute, Inc., 1997. Emergency Shut-Off Systems for Bulk Transfer of Chlorine, Pamphlet 

57, Edition 3, October 1997. 

Trinity Consultants, 2003. DPC Enterprises Accidental Chlorine Release, Dispersion Modeling Analysis, 

May 12, 2003. 

Updyke, L. J., 1982. “Method for Calculating Water Distribution in a Chlorine Condensing System,” 25th

Chlorine Plant Operations Seminar, February 17, 1982. 

U.S. Chemical Safety and Hazard Investigation Board (USCSB), 2002. Safety Advisory: Chlorine 

Transfer Hose Failure, November 2002. 
DPC Festus 05-30-03 

81 

U.S. Environmental Protection Agency (USEPA), 2000a. General Guidance for Risk Management 

Programs (40 CFR Part 68), RMP Series, EPA 550-B-00-008, May 2000. 

USEPA, 2000b. Risk Management Program Guidance for Chemical Distributors (40 CFR Part 68),

RMP Series, EPA 550-B-00-005, May 2000. 
DPC Festus 05-30-03 

82 

APPENDIX A: Dry Chlorine Corrosion 

A.1 Definition 

The Chlorine Institute (2000b) defines dry chlorine as “liquid or gaseous chlorine with its water content 

dissolved in solution.” It is important to understand that even dry chlorine contains some very low levels 

of water. When not all the water is dissolved in solution because of system conditions (e.g., temperature 

or pressure)1

 or contamination (e.g., atmospheric moisture intrusion), the excess water forms a second 

aqueous phase. It is this water-rich phase that creates corrosion problems within a system in dry chlorine 

service. At ambient temperature, dry chlorine contains less than 50 ppm water. 

A.2 Corrosion Mechanism 

In dry chlorine service, carbon steel is the most commonly used material of construction for system 

piping. The iron in carbon steel is reactive with dry chlorine: 

2 Fe + 3 Cl2 Æ 2 FeCl3 [Eq A-1]

The reaction product, ferric chloride (FeCl3), forms a passive layer on the steel surface, which protects the 

underlying iron from further attack by chlorine. 2 Carbon steel is corrosion resistant to chlorine as long as 

high water concentrations or temperatures do not deliquesce the protective layer (Chlorine Institute, 

2002).3

 

1

 The water content at which chlorine is dry varies with temperature (e.g., chlorine with a water content of 30 parts 

per million (ppm) at a temperature of 50 degrees Fahrenheit (o F) is dry; the same chlorine (30 ppm) at a temperature 

of -4o F is wet. 

2

 Ferric chloride is a very hygroscopic salt; it absorbs moisture/water very quickly when exposed to the atmosphere, 

which accelerates the overall corrosion rate and buildup of products in the system. 3

 Deliquesce: to dissolve and become liquid by absorbing moisture from the air. 
DPC Festus 05-30-03 

83 

The corrosion mechanism for chlorine attack on steel is a water-rich phase or an increase in temperature. 

In either case, ferric chloride forms; this solution is an electrolyte, a very strong oxidizer, and a strong 

acid. 

The water-rich phase not only dissolves the protective layer of ferric chloride, but also forms an acid 

medium by reaction of chlorine with water (Updyke, 1982). The chlorine-water reaction forms 

hypochlorous acid (HOCl) and hydrochloric acid (HCl): 

Cl2 + H2O Æ HOCl + HCl [Eq A-2]

The acids and the dissolved ferric chloride form a concentrated solution that is corrosive to steel. 

A.3 Sources of Corrosion 

A.3.1 Dryer System 

The compressed air used to “pad” the tank car is a potential source of moisture. Pad air at approximately 

175 pounds per square inch gage (psig) is piped to the vapor space of the tank car to push liquid chlorine 

into the DPC system. The compressor is equipped with a moisture analyzer and an automatic 

regenerating dessicant dryer that uses a moisture-absorbing material, such as aluminum silicate. (One 

dryer is in service while the other is heated to drive off moisture.) 

The moisture analyzer had provided the same exact readings for several months, which may have 

indicated a malfunction. Maintenance did not include a check of the dew point indicator. The last dryer 

system maintenance inspection was conducted in July 2002. 

As further evidence of inadequately dried air, inspection of one of the emergency shutdown (ESD) valve 

actuators revealed liquid moisture trapped within the actuator mechanism. This moisture is likely to have 
DPC Festus 05-30-03 

84 

originated in the air used to power the actuator. The plant air dryer was upgraded prior to the chlorine 

release because of excessive moisture clogging the plant sandblasting equipment. 

Moisture in the plant air system was a key indicator of the potential for similar problems with the pad air 

dryer. If employees had been trained on the criticality of the dryer system, they would have known to 

conduct preventive maintenance. 

A.3.2 Atmospheric Moisture 

Whenever chlorine piping is disconnected from a system or tank car, trace amounts of chlorine may 

remain in the hose or piping, or may evolve from the Teflon liner. Combined with ambient moisture, this 

chlorine can produce a thin film of corrosion products that is washed downstream the next time the piping 

is used. 

The practice at DPC is to cap hoses, pad air supply and unloading assemblies, and system piping 

immediately upon disconnection or when not in use. There was a potential for moisture intrusion if the 

packagers did not immediately cap all assemblies. 

At DPC Festus, the piping system is also evacuated, held under vacuum each night, and evacuated again 

in the morning prior to being tested for leaks with chlorine vapor. When the system is under vacuum, 

there is a slight potential for moist ambient air to intrude via minor joint and fitting leaks. 

A.3.3 Tank Car 

Chlorine producers employ safeguards to ensure that the chlorine loaded into tank cars is shipped with no 

free moisture. Tank cars are visually inspected, pressure tested, and dried with compressed air. The air 

exiting the tank cars is analyzed, and airflow continues until the dew point of the exiting air is at or below 

–40°F, which corresponds to a moisture content of 0.1 milligram per liter (mg/L) or 125 ppm. The cars 

are loaded with liquid chlorine that is dried to the same standard. In the case of the August 14 release, 
DPC Festus 05-30-03 

85 

this information—along with the certificate of analysis for the shipment—provides the basis for the CSB 

assertion that the tank car is unlikely to have been the source of corrosion. 
DPC Festus 05-30-03 

86 

 APPENDIX B: Additional Details on DPC Festus Facility 

B.1 Facility Layout 

The DPC Festus site is triangular in shape, with a fenced perimeter and a gated main entrance off 

Highway 61. It includes a chlorine repackaging building, a storage tank area, and an office building. 

The repackaging building houses the cleaning, preparation, and fill areas for the cylinders and containers; 

the air compressor and compressed air dryer room; a breakroom; and the sodium hypochlorite (bleach) 

production area. 

Tank cars are brought into the facility through a rail spur along the northwest corner of the site. A storage 

area located on the eastern side of the repackaging building contains several bulk storage tanks of sodium 

hydroxide (caustic soda), bleach, and wastewater. The three chlorine tank car unloading stations are 

located along the northern side of the repackaging building. Each station is equipped with three flexible 

transfer hoses to connect plant piping to the tank car. 

B.2 Chlorine Repackaging Process 

B.2.1 Tank Car Unloading 

The railroad company moves a tank car to the assigned unloading station. Only one tank car is unloaded 

at a time. 

Because there are no working platforms at the unloading stations, a DPC packager uses the car ladder to 

climb to the top of the tank car. The packager then opens the cover of the protective dome and tests for 
DPC Festus 05-30-03 

87 

leaks using a spray bottle of ammonia solution.4

 If no leak is detected, the packager removes the plug in 

the vapor valve (valve D) opening5

 and threads in the “pad” air supply assembly. Pad air is used to help 

push the liquid chlorine out of the tank car into the plant piping (Figure B-1). The plugs from the two 

liquid valves (valves A and C) are then removed, and two chlorine unloading assemblies are threaded in. 

Each of the three assemblies is attached to a chlorine transfer hose, which connects the tank car to process 

piping. The packager then uses the ammonia solution to test the connections for leaks. 

Figure B-1. Pad air supply assembly. 

At all three unloading stations, the liquid chlorine system piping ties into a common header located in the 

repackaging building. The header feeds a main supply line, which branches off and supplies chlorine to 

the fill stations. 

 

4

 Ammonia reacts with chlorine to form a visible white aerosol cloud (ammonium chloride). 

5

A plug is threaded into the valve opening to prevent the inadvertent release of material. 
DPC Festus 05-30-03 

88 

The tank car remains connected to plant piping via the chlorine transfer hoses until all chlorine is 

unloaded. The hoses are then disconnected from the car, capped, and left hanging from the process 

piping. The pad air supply and chlorine unloading assemblies are also disconnected from the tank car and 

capped on both ends. 

The DPC Standard Operating Procedures Manual describes the sequence of actions necessary to connect 

plant piping to the chlorine tank car. It specifies that both the chlorine transfer hoses and the unloading 

and pad air supply assemblies need to be immediately capped. 

B.2.2 Pad Air Supply and Chlorine Unloading Assemblies 

Two assemblies are needed for chlorine tank car unloading at DPC Festus because both of the car’s liquid 

valves are used. The air-actuated valves are a critical part of the ESD system (Figure B-2). 

• The first component of the air supply assembly is a threaded 1-foot-long, 1-inch-diameter 

carbon steel pipe. This end of the assembly is passed through an access hole on the side of 

the tank car dome and threaded onto vapor valve D. A two-bolt flange is threaded onto the 

other end of the steel pipe. A screwed-end ball valve plus actuator, a pressure gauge, a gate 

valve, and several lengths of 1-inch pipe are then attached to this flange. 

• The first component of the chlorine unloading assembly is a threaded 2-foot-long, 1-inchdiameter carbon steel pipe that attaches to the tank car in a similar manner as the air supply 

assembly (valves A and C). A 90-degree elbow is threaded onto the unattached end, and a 

two-bolt flange is added for attachment to the air-actuated valve (Figure B-2). 
DPC Festus 05-30-03 

89 

Figure B-2. Piping assembles for tank car unloading. 

B.2.3 Pad Air and Plant Air Supply 

The pad air supply system provides air pressure to facilitate transfer of chlorine from the tank car to the 

fill stations. This system has a dedicated compressor, air drier, and piping. A malfunction of the pad air 

system drier could potentially introduce wet air into the tank car, which would contaminate the chlorine 

and create corrosion problems in the transfer piping. 

The plant air supply system—which provides air pressure to air-operated instrumentation throughout the 

facility, including the ESD actuators and valves—also has its own compressor, air drier, and piping. 
DPC Festus 05-30-03 

90 

During normal operation, plant air supplies the force to overcome the actuator spring pressure, thus 

keeping the ESD valves open.6

 When solenoids controlling the ESD valve actuators are deenergized, the 

plant air port closes and the atmospheric port opens to relieve air pressure and allow the actuator spring to 

close the valve. 

B.3 Tank Car Specification 

The tank car was a U.S. Department of Transportation (DOT) 105J500W specification car manufactured 

in 1981, with a carbon steel pressure tank and insulation covered by a steel jacket. Its water capacity was 

17,300 gallons. 

PLM Tank Car Management Services Canada Ltd. owned the tank car. The car received a maintenance 

inspection and service in May 2000.7

 It was leased to Westlake CA&O Corporation, a Calvert City, 

Kentucky, manufacturer of chlorine, which shipped a full load of chlorine to DPC Festus on July 12, 

2002. A quality analysis performed by Westlake prior to shipment found the material to be 99.944 

percent chlorine. This purity was well within DPC purchase specifications. 

B.4 Repackaging System Standby and Shutdown Modes 

Although all filling stations are isolated in standby mode, the plant piping system contains chlorine and is 

not isolated from the tank car. The tank car liquid valves A and C and the pad air vapor valve D are open. 

The ESD valves within the process piping system and on the tank car air supply and unloading assemblies 

are also open. 

 

6

 Typical instrument air hoses are used to provide airflow to the actuators. 7

 During this inspection, various safety systems were verified, including the pressure relief valve and excess flow 

valves. DOT requires chlorine tank car pressure relief valves to be inspected every 5 years and an overall tank 

inspection every 10 years. 
DPC Festus 05-30-03 

91 

In shutdown mode, the process piping is evacuated of chlorine and put under vacuum conditions. The 

piping system is isolated from the tank car by manually closing all car valves and pressing the ESD 

button to activate (close) all air-actuated ESD valves. 

In both standby and shutdown modes, the chlorine transfer hoses remain connected to the tank car. 

B.5 DPC Hose Order Arrangement 

Prior to April 2000,8 DPC used chlorine transfer hoses with a Monel inner lining9 rather than Teflon. 

DPC switched to the Crane-Resistoflex Teflon-lined CTH design for future replacements because it 

offered a greater degree of flexibility. 

DX Distribution Group made arrangements with Branham Corporation to fabricate the Crane-Resistoflex 

chlorine transfer hose. The company placed its first order (for the Festus facility) with Branham for the 

Crane-Resistoflex CTH design10 on July 24, 2000. The hose description used in this purchase order was 

of the old Monel-lined design (see Figure B-3). Branham corrected the error because its arrangement 

with DPC was to fabricate Teflon-lined hoses. On July 25th, Branham shipped to Festus the newly 

fabricated hose. 

All DPC hose descriptions on purchase orders to Branham placed after July 24, 2000—including the 

March 18, 2002, order—stated “Monel-lined.” On all orders prior to March 18, Branham had supplied 

DPC with the correct Teflon-lined CTH design despite the incorrect hose description on purchase orders. 

Furthermore, two of the three hoses supplied to DPC Festus as part of the March 18 order were correct, 

 

8

 In May 1999, all nine Monel-lined hoses at the three tank car unloading stations at DPC Festus were replaced. 

These chlorine transfer hoses had Monel inner lining rather than Teflon. 

9

 Crane-Resistoflex does not manufacture Monel-lined chlorine transfer hoses. 

10Tank car unloading hose specifications: 1-inch, 11-foot-long hose with Schedule 80 Monel 400 end fittings, a high 

density polyethylene (HDPE) spiral guard, and shrink-wrapped paper hose identification tags. 
DPC Festus 05-30-03 

92 

which suggests that the hose mixup may be explained by an error in the supply chain rather than an error 

in the purchase order. 

Figure B-3. DPC purchase order, flex hose for chlorine railcar and truck unloading. 
DPC Festus 05-30-03 

93 

APPENDIX C: Inspection, Schedule for Chlorine 

Repackaging System 

Table C-1 lists the inspection/testing schedule followed by DPC Festus for each of the chlorine 

repackaging system components. 

Table C-1 

Chlorine Repackaging System Inspection Schedule 

 System Components Inspection/Testing Frequency 

System piping Inspect and thickness test every 5 years 

Other system components (valves, rupture 

discs, limit switches, etc.) Repair/replace as necessary 

Air-actuators Repair/replace as necessary 

Emergency shutdown system (alarms, lights, 

buttons, etc.) Quarterly test 

ESD valves Repair/replace as necessary 

Chlorine detection system Calibrate/inspect annually 

Chlorine unloading assembly Clean and inspect after each car unloading; 

 replace as necessary 

Pad air supply assembly Clean and inspect after each car unloading; 

 replace as necessary 

Pad air dryer Annual inspection 

Plant air dryer Annual inspection 

Pad air compressor Semiannual inspection 

Plant air compressor Semiannual inspection 

Chlorine transfer hose

 Daily external inspection; 

 clean and inspect after each car unloading; 

 replace 2 years from date of fabrication 
DPC Festus 05-30-03 

94 

APPENDIX D: Critical Elements of Emergency 

Response Plan 

An emergency response plan should include all of the following elements: 

• Procedures for responding to an emergency based on type of event and potential effects. 

- Employee-managed response 

- Employee evacuation to a preplanned safe zone area 

- Local community emergency response. 

• Procedures for informing the public and emergency response agencies. 

• Delegation of responsible authorities (i.e., incident command system) for making decisions, 

monitoring response actions, and recovering back-to-normal operations. 

• Specific instructions for shutting down equipment and processes. 

• Facility evacuation procedures, including a designated meeting site outside the facility and a 

process to account for all employees after an evacuation. 

• Emergency response equipment requirements and procedures for use, inspection, testing, and 

maintenance. 

• Training requirements for employees who are responsible for rescue operations, medical 

duties, hazardous response, and firefighting. 

• Procedures for update, review, and redistribution of the emergency response plan. 
DPC Festus 05-30-03 

95 

• Procedures for coordination of related activities with local emergency response and planning 

officials. 

The emergency response plan also needs to consider whether: 

• Other nearby facilities may pose a hazard in the event of an emergency. 

• Toxic materials themselves may cause unsafe conditions. 

The chemical manufacturer or supplier of toxic materials provides material safety data sheets (MSDSs), 

which describe potential hazards; list precautions for handling, storing, or using the substances; and 

outline emergency and first-aid procedures. This information should be easily accessible to employees 

and the community. 

All employees must be trained on how to respond to potential emergencies. The emergency response 

plan should be reviewed with all employees when it is initially developed, when employee responsibilities 

change, and whenever the plan itself is revised. It should be kept in a location that is easily accessible to 

all employees. 
DPC Festus 05-30-03 

96 

APPENDIX E: Fault Tree Analysis, Hose Failure 

Hose ruptured 

8/14/02 

Excessive 

pressure in hose 

*Maximum pad air 

pressure: 175 psig. 

Hose structurally 

weakened 

Mechanical Chemical attack

damage 

Hose structural 

braid corroded 

from inside 

Hose structural 

braid corroded 

from outside 

Chlorine 

permeated hose 

inner lining 

Braid material 

incompatible 

with wet 

chlorine 

Page 

2 

Misuse 

Wear 

and 

tear 

Sabotage 

Teflon is 

permeable 

to chlorine 

Hose 

inner liner 

is Teflon

Ambient 

moisture 

present 

Chlorine 

residue 

present on 

outside of 

hose 

Liquid 

trapped 

in hose 

High pad 

air 

pressure*

Moisture 

present in 

structural 

braid layer
DPC Festus 05-30-03 

97 

From 

Page 1

Material 

incompatible with 

wet chlorine 

Hose was braided 

stainless-steel 

DPC unable to 

verify hose 

material 

DPC received 

incorrect material 

Stainless-steel 

pits and cracks 

in presence of 

moisture and 

chlorine 

Bulk 

material 

supplier 

error 

Fabricator 

error 

No visual means 

to distinguish 

stainless-steel 

from Hastelloy 

braided hose 

Materials 

testing and 

verification 

methods not 

used 

AND GATE AND GATE 

OR GATE 

END 
DPC Festus 

APPENDIX F: Causal Factors Diagram, Chlorine Release 

Materials testing / 

verification methods 

not used

Shipping documents from 

Branham indicate Hastelloy

 was sent to DPC

Chlorine monitor detects 

chlorine and sounds alarm

Time: ~9:20 a.m. 

Moisture intrudes into 

chlorine system

Valves do not close due 

to corrosion buildup

Chlorine monitoring 

system initiates shutdown 

sequence

Time: 9:20 a.m.

ESD system fails

Time: 9:20 a.m.

Wet chlorine reacts with 

steel pipe

Excess flow valve doe

close

Time: 9:20 a.m

Chlorine release occurs 

Time: 9:20 a.m.

4/5 valves at rail rack do 

not close due to corrosion

Actuator torque LTA to 

close valves

Stainless-steel hose 

incompatible with 

chlorine service 

Branham fabricated hose of

stainless-steel 

Hose installed

Date: 6/15/02

Hose ruptured on 8/14/02

Time: ~9:20 a.m.

Stainless-steel hose 

installed instead of 

Hastelloy; corrosion led to 

weakened structural 

integrity

Actual flow may have 

less than set poin

Hastelloy braid hose

 identical in appearance to 

stainless-steel hose

DPC acquires Festus 

facility from Jones 

Chemical Co.

Date: 8/20/98

DPC QA

LTA

Supplier QA

LTA

Mechanical integrity

1 2 3 4 5 6 7 8 

 Training and procedures
DPC Festus 

A 

911 notified

Time: 9:27 a.m

R-7 (fire department) 

initiates evacuation of 

Blue Fountain moblie 

home park

Time: 9:37 a.m

HAZMAT duty officer 

paged

Time: 10:45 a.m.

HAZMAT truck at north 

command post

No lights or sirens on 

response vehicles

Emergency responders 

scattered across county

Time: 11:15a.m.

Full HAZMAT assembly at 

south command post

Time: ~11:45 a.m.

HAZMAT entry preparation

Responders take time 

to assemble 

Jefferson County 

emergency response 

planning 

LTA

Time: 12:21 p.m.

HAZMAT enters and shuts 

off leak 2:54 after initial 

report 

Date: 8/14/02

DPC attempts onsite 

cleanup

12 13 14 15 16 17 18 

HAZMAT volunteers seek 

permission to leave jobs