U.S. C HEMICAL S AFETY AND H AZARD I NVESTIGATION B OARD


# INVESTIGATION REPORT

R EPORT N O . 2002-04-I-MO M AY 2003 

# C HLORINE 

# R ELEASE (66 Sought Medical Evaluation)



## DPC E NTERPRISES 

## , L.P. F ESTUS , M ISSOURI A UGUST 14, 2002



## K EY 

## I SSUES 

## :

• M ECHANICAL I NTEGRITY

• E MERGENCY MANAGEMENT

• C HLORINE T RANSFER H OSE S UPPLYDPC Festus 05-30-03

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## Contents

EXECUTIVE SUMMARY .............................................................................................................. ..........11 1.0 INTRODUCTION ................................................................................................................... ......13 1.1 Background..................................................................................................................... ...............13 1.2 Investigativ e 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 Ov erview............................................................................................................... ............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............................................................................................................31DPC Festus 05-30-03

3 3.2.3 Tank Car Excess Flow Valve............................................................................................31 3.2.4 Access to Emergency Response Equipment .....................................................................32 3.2.5 Facility Evacuation ...........................................................................................................3 2 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 Po sitioning .......................................................................................................... ........41 4.5 ESD System Testing ............................................................................................................. .........43 4.6 Excess Flow Valve.............................................................................................................. ...........44 5.0 ANALYSIS OF INCIDENT..........................................................................................................4 6 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 .............................................................................................................5 2 5.2.3 Auditing of Inspection Procedures....................................................................................52 5.2.4 Auditing of Schedules.......................................................................................................53DPC Festus 05-30-03

4 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 Emergenc y 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 Dist ribution Process ......................................................................................69 6.0 ROOT AND CONTRIBUTING CAUSES....................................................................................71 6.1 Root Causes .................................................................................................................... ...............71 6.2 Contributing Causes............................................................................................................ ...........72 7.0 RECOMMENDAT IONS...............................................................................................................7 4 8.0 REFERENCES ..................................................................................................................... .........79 APPENDIX A: Dry Chlorine Corrosion............................................................................................ ........82 A.1 Definition..................................................................................................................... ..................82DPC Festus 05-30-03

5 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, Ho se Failure ................................................................................. ...96 APPENDIX F: Causal Factors Di agram, Chlorine Release.......................................................................98DPC Festus 05-30-03

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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, A ngle 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 Arrange ment at Unloading Station .......................................................28 13 Actuator Indicator Show ing 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 ............................................................................40DPC Festus 05-30-03

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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 ..................................................................................8 9 B-3 DPC Festus Purchase Order for Flex Hose fo r Chlorine Railcar and Truck Unloading................92



## Tables
1 Repackaging System Components in Standby and Shutdown Modes...........................................30 C-1 Chlorine Repackaging System Inspection Schedule......................................................................93DPC Festus 05-30-03

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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 a nd Emergency Response Standard (OSHA) HDPE High density polyethylene IDLH Immediately dangerous to life or health lb/hr Pounds per hourDPC Festus 05-30-03

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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)DPC Festus 05-30-03

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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, a nd Countermeasures (Oil Pollution Act) XRF X-ray fluorescenceDPC Festus 05-30-03

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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 Enterp rises, L.P., near Festus, Missouri. The facility repackages bulk dry liquid chlorine into 1-ton co ntainers 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” (NIO SH, 2003). Although the wind direction on the day of the release carried the majority of the chlorine plume away from neighbor ing 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 overn ight observation. The release affected hundreds of other nearby residents and employees, and the communi ty 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 sp ecifications prior to installation and use.

• Branham Corporation, the CTH fabricator/distri butor, 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

12 • 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 manufactur ers 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 de tect corrosion in the chlorine transfer and pad air systems before it caused operational and safety problems.

• The overall emergency response and planni ng system had serious deficiencies: - The community notification system was ineffi cient, which resulted in additional exposure to neighboring residents and businesses. - DPC emergency preparedness planning was deficient. - Jefferson County community emergency prepar edness planning was inadequate for an incident of this magnitude. CSB makes recommendations to DPC Enterprises, Fe stus; DX Distribution Group (DPC corporate); Branham Corporation; Jefferson County Emergency Management Ag ency; Missouri State Emergency Response Commission; Missouri Department of Natural Resources; Agency for Toxic Substances and Disease Registry; The Chlorine Institute, Inc.; Nationa l Association of Hose and Accessories Distributors; and National Association of Chemical Distributors.DPC Festus 05-30-03

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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 En terprises, 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 even ts 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.DPC Festus 05-30-03

14 Chlorine is a toxic chemical. When inhaled in high concentrations, chlorine gas causes suffocation, constriction of the chest, tightness in the throat, a nd edema of the lungs. At around 1,000 parts per million (ppm), 1 it is likely to be fatal after a few deep br eaths. According to the National Institute for Occupational Safety and Health (NIO SH, 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 s hort 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 pa rk, 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 pa rk 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 followi ng 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

15 • 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 morn ing of August 15. CSB co nducted interviews with DPC employees and members of the community, review ed relevant company documents and scientific literature, and examined physical evidence. CSB al so 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, CS B visited another chlorine repackaging facility (DXI Industries, Inc.), in Houston, Texas, to evaluate ch lorine handling procedures. CSB also contacted other chlorine repackagers and reviewed recommended practices of The Chlorine Institute, Inc. Other investigative organizations onsite included th e 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 Agen cy for Toxic Substances and Disease Registry (ATSDR) assisted CSB in investigating emer gency 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

16 Chlorine gas can be liquefied by the application of pressure at reduced temperatures to form a clear, amber-colored liquid. Liquid chlorine (a liquefied comp ressed gas) is more economical to ship and store. Other than at large production facilities, liquid chlori ne is typically stored and shipped in 150-pound cylinders, 1-ton containers, or 55- and 90-ton tank car s. 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, creati ng 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 br ass 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, plas tic 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 ga s 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 th e eyes, nose, throat, and lungs. Prolonged exposure or exposure to high concentrations may be fatal, as ou tlined 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 chlo rine and vaporized gas escaping from pressurized containment can cause frostbite. OSHA and EPA regulate the manufacture, storage, a nd use of chlorine. The OSHA Process Safety Management (PSM) standard requires compliance wi th a variety of provisions designed to protect workers at facilities that handle chlorine in am ounts greater than 1,500 pounds (29 CFR 1910.119,DPC Festus 05-30-03

18 Appendix A). Similarly, one of the objectives of th e EPA Risk Management Program (RMP) rule is to protect the public from facilities that handle more than 2,500 pounds of ch lorine (40 CFR 68.130). 

## 1.4 DPC Enterprises Festus Facility AG Kit Chemical Company initially developed the F estus 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 repackag ing facility, five other similar facilities, and two warehouses. It is part of the DX Distribution Gr oup 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 Pla ttin 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 packagin g 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 th e piping system is directed to the bleach production process. A vacuum is pulled and the system is le ft 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 connectedDPC Festus 05-30-03

19 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.DPC Festus 05-30-03

20 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.DPC Festus 05-30-03

21 • Goodwin Brothers Construction a nd 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 f acility, 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.DPC Festus 05-30-03

22 Figure 6. Aerial view of DPC Festus facility and surrounding area.DPC Festus 05-30-03

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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 ta nk 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 cylinde rs and 1-ton containers onto trucks for distribution.

• Cleaning and preparing empty cylinde rs and containers for reuse. In addition to repackaging chlorine, the Festus f acility also runs a continuous bleach manufacturing process. 

## 2.2 Chlorine Tank Cars A chlorine tank car has four manually operated angl e 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 a nd 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

24 Figure 7. Schematic of tank car protective dom e, 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 liqui d valve (Figure 8). Liquid chlorine is withdrawn from inside the tank car through eduction pipes 3 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

25 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 e quipped 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 (p lastic), 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 tran sfer hose assemblies with similar dimensions for chlorine tank car unloading or for any other operation with in 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-actuate d ball valves (ESD valves) at the unloading stations are critical components of the ESD system (Figure 11) , which is activated either automatically orDPC Festus 05-30-03



### 26 Figure 9. Typical fully asse mbled chlorine transfer hose.

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

27 manually by pressing one of several ESD bu ttons 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 th e air supply and chlorine unloading assemblies, and two on the plant side piping (Figure 12). Air-ope rated 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 ES D system is manually activated, the solenoids 5 controlling the actuators are deenergized—which cau ses 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

28 Figure 12. Schematic of ESD valv e 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 requi re 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 pounds 6 of chlorine was connected to station #3, which served all chlorine filling operations until th e time of the release on August 14. The facility repackaging production records indicate that the car cont ained 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 St andby and Shutdown Modes The chlorine repackaging system is on standby duri ng morning and afternoon breaks, lunch, and cylinder changeouts. When all cylinder filling operations are co mplete 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 packager s, a truck driver, and the operations manager 8 started up chlorine filling and container preparation opera tions for the day. Around 9:00 am, these employees placed the repackaging system on standby mode and t ook 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, incl uding assisting packagers with cylinder filling operations.DPC Festus 05-30-03

30 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 releas e at tank car station #3.

The leak activated an area chlorine detection m onitor audio alarm. Upon hearing the alarm, the employees in the breakroom tried to identify the sour ce of the leak. They found chlorine entering the repackaging building through an open access door near tank car station #3. Because of the apparentDPC Festus 05-30-03

31 magnitude and intensity of the release, the employ ees evacuated the building. The operations manager pushed the ESD button (Figure 15) as he exited in an a ttempt 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 intende d to close either automa tically based on chlorine detection levels or through hand- operated ESD buttons. Although bot h 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 th e flow of liquid chlorine if the angle valve is broken off in transit. It may close if a catast rophic leak involving a broken connection occurs but it is not designed to act as an emergency shut-o ff device during transfer (Chlorine Institute, 1997; p. 14).DPC Festus 05-30-03

32 The tank car excess flow valves were designed to clos e only if the flow rate exceeds their set point (15,000 lb/hr). These valves rema ined open during the release. 

### 3.2.4 Access to Emerg ency 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 rep ackaging 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, includi ng 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 aw ay, 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 th e direction of Goodwin Br others Construction and Intermodal Tire, though it is likely that it migrated into the adjacent Blue Fountain mobile home parkDPC 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 approxima tely 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 th at 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 plum e and had to seek medical evaluation. Neither of the businesses had an alternative escape route. Hundreds of residents—including occupants of an ass isted living facility and a learning center, both part of the Jefferson Memorial Hospital system; and stude nts 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 evalua tion 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 pe rsons 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 a ffect 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 releas e began—the DPC operations manager called 9-1-1 to report the chlorine release. The Jefferson C ounty R-7 volunteer fire department arrived on scene within 10 minutes. The R-7 fire chief immediately re quested 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 depa rtment 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 c ounty responders). Emerge ncy response personnel from the north post notified the Jefferson Memorial assisted living facility and the lear ning center and St. Pius High School to shelter-in-place. The Jefferson Count y 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 sher iff’s department and the highway patrol shut down Interstate 55. The ambulance service transported six people from neighboring areas with symptoms ofDPC Festus 05-30-03

35 chlorine exposure to Jefferson Memorial. The majori ty 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 vol unteers, who live and work in various parts of the 660-square-mile county. The team duty officer r eceived 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 sev eral 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 va lve that supplied the ruptured hose (valve A), but the release did not stop. They then closed the other li quid valve (valve C) and vapor valve D halfway; then they completely closed both valves. Th e 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 identif ied a 4- by 4-foot formation of chlorine hydrate 10 next to the tank car (underneath the ruptured hose), but it was determined to pose no imminent danger.

10 Chlorine ice or chlorine hydrate (Cl 2 –8H 2 O) 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 t he 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 Depa rtment of Natural Resources conducted monitoring throughout the facility as well as the neighborin g 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 ar ound tank car station #3.

In consultation with DPC corporate personnel, the oper ations manager decided to remediate the chlorine hydrate formation. No remediation plan was devel oped 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. Howe ver, 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 th ree men received medical evaluation. The hydrate formation continued to give off minor am ounts 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 a ttached at tank car station #3 initiated the chlorine release (Figure 19). Reconstructive analysis determin ed why the chlorine transfer hose ruptured and why the ESD valves failed to close. The excess flow valv es were dismantled and inspected to determine if they should have closed.

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



## 4.1 Hose Construction The CTH assembly used at DPC Festus was specifie d 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 nonmetallic 12 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 ch lorine because of their hydrocarbon st ructural makeup. This reactivity is avoided with some plastics in which fluorine atoms are su bstituted into the hydrocarbon molecule (e.g., Teflon). Rupture pointDPC 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 a ttached 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 br aiding scattered throughout the immediate area. The external spiral guard kept the ruptured hose att ached 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 exposu re 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 ho se 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 discu ssed 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 hos e 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 conclud es that corrosion of the 316L braid layer weakened the structural integrity of the hose. Normal ope rating pressure, in combination with repetitive bending forces, caused the hose to rupture and release chlori ne. (See fault tree analysis of hose rupture in Appendix E.) 

## 4.4 ESD Valve Positioning Section 2.4 describes the DPC Festus ESD system. CS B 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 fa iled 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 lin e 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, conn ected to the ruptured chlorine transfer hose. Determining the actual positioning of the five ESD va lves at tank car station #3 led CSB investigators to conclude that the chlorine flowed through the partia lly opened ESD valve #3, to the attached intact liquid CTH line, into the plant side piping, and back throug h 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 conti nued 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 ot her 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 tankDPC 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 valv es #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 so lenoids controlling the ESD valv e 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 availabl e 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 afte r the release. Therefore, a second set of piping assemblies—not in use at the time of the incident—w as 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 mo isture-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 th e excess flow valve set point of 15,000 lb/hr. The flow may ha ve 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 ho ses 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 ordere d three 1-inch chlorine transfer hoses for tank car unloading operations at Festus. Appendix B furthe r 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 ch lorine 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 ope ration 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 transf er hose with Hastelloy C braid. 17 Visual inspection and X-ray fluorescen ce (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—cause d 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, st enciling, 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 th e manufacturing process for various types of hoses. CSB ruled out the possibility of a mixup at DPC F estus because the facility did not use any other hose assemblies with dimensions similar to the ch lorine transfer hose (1 inch, 11 feet).DPC Festus 05-30-03

48 From the site visits and revi ew of documentation, CSB investigators identified the following opportunities for error because of the inability to vi sually 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 missi ng, 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 conduc ts positive materials identification (PMI) testing of CTH shipments . (The North Carolina headquarters of Crane-Resistoflex performs PMI on bulk chlorine transfer hose as rolls ar e 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 sh ipping 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 verifica tion 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 CSBDPC Festus 05-30-03

49 investigators were unable to determine exactly wher e 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, nick el) in various alloys, such as stainless-steel and Hastelloy. It is particular ly useful in differentiating metallic parts of process components. Although PMI may not be a viable optio n on all types of chlorine transfer hose because of varying outer materials of constructi on, 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 bot h Hastelloy C and stainless-steel braidings and contracted with a third party to analyze the samp les via XRF nondestructive t esting, a commonly used PMI test method. The analysis demonstrated that PMI testing would have diffe rentiated Hastelloy C-276 braid from 316L stainless steel. DPC relied on visual inspection and shipping documentation 19 to confirm that the chlorine transfer hose met its specifications. The documentation received fro m 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 pe rformed on CTH shipments upon receipt from Branham or prior to installation. Thus, CSB concludes that DPC had no procedure in pl ace to verify that the ch lorine 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 a bove the OSHA PSM and EPA RMP threshold quantities (as discussed in Section 1.3). The MI program for the Festus facility was based on dr y chlorine service requirements. The materials of construction were appropriate for dr y 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 repack aging 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 identi fy or prevent corrosion. CSB investigators identified the followi ng deficiencies in the MI program:

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

• Insufficient training of packagers on the catast rophic 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—traini ng that could have heightened employee awareness to deteriorating equipment conditions. As described below, CSB i nvestigators 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 ch ecks at DPC Festus were inadequate and poorly supervised. For example, one of the requirements in the chlorine system startu p 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, pr ior to startup, and looked for visual or physical clues as to any potential problems. With appropriate tr aining 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 tr ansition, there were periods with no management supervision of day-to-day ope rations, including inspections. Although a new manager was hired and assigned day-to-d ay supervision responsibility in January 2002, he was inexperienced in chlorine repackaging ope rations. DPC provided some training on chlorine repackaging, but it was inadequate for his safety responsibilities and did not sufficiently cover theDPC Festus 05-30-03

52 importance of preventive maintenance and inspecti on. The new manager assumed that the packagers were performing their tasks properly because of th eir combined chlorine repackaging experience. 

### 5.2.2 Operator Training Although DPC provided training on elements of th e 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 th e 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—traini ng that could have heightened employee awareness to deteriorating equipment conditions. 

### 5.2.3 Auditing of Inspection Procedures The review and update of MI progr am standard operating procedures is critical to ensure the optimal and safe performance of process equipment. DPC did not ad equately audit its standa rd 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 pr ocedures 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 insp ected. The DPC inspection and tes ting 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 de finition of “regular” is left up to the facility to determine based on indivi dual site conditions. In dry chlorine service, corrosion sh ould 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 schedul es should be routinely audited to ensure that their intervals are of adequate duration to identify a nd prevent process safety problems, such as corrosion, before there is a risk of system failure. The intern al 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 test ed 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 in spected for mechanical integrity.” The Center for Chemical Process Safety (CCPS, 1997) discusses emerge ncy isolation of releases, design and operation of emergency ESD valves, and the need for routine in spection and testing. CCPS states: “Testing of isolation devices needs to be a complete functi onal 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. Rou tine testing of the ESD valves to verify that theyDPC Festus 05-30-03

54 are, in fact, closed after actuating the system—combi ned 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 im portance of keeping the system free of moisture or the consequences of failing to do so. This lack of awar eness 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 cr eate significant corrosion problems within carbon steel piping (Roberge, 2000). As discussed in Section 4.5, CSB concludes that the valves did not close b ecause 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 corrosi on-producing moisture (see Appendix A for details):

• Pad air used to provide pressure for the tr ansfer 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 ch lorine repackaging piping system.

The DPC Festus MI program was not successful in pr eventing corrosion within the chlorine repackaging system because it did not adequately address rela ted 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 a ll 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-T o-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 el ements of these regulations. Appendix D provides information on procedures for community notificatio n 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 co mmunity 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. 22 The 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 (emerg ency response assessment).

• Inadequate procedures for training and drills.

• Inaccessible location of emergency response equipment.

• Lack of clear guidelines for post-incident remedi ation (i.e., planning, handling, and disposing of hazardous materials). These deficiencies resulted in DPC’s inadequate prepar ation for a large uncontrolled release. CSB does not question the DPC decision to evacuate the f acility 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 improveme nt 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 ade quate 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 comp any 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 wh y, the means by which they will be contacted, the time frame for notification, and the inform ation that will be provided” (USEPA, 2000a).DPC Festus 05-30-03

58 Although DPC had procedures and effectively notifie d local agencies and emergency response personnel of the release, it did not adequately inform the pub lic. The emergency response plan contained contact numbers for the local emergency planning committ ee (LEPC), nearby businesses, and neighbors— including the construction and tire retreading compa ny, the mobile home park, and the owner of an adjacent farm—but it did not assign responsibility for no tification to any specific personnel. Emergency responders went door-to-door at the Blue Fountain mob ile 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 va lves 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 r esidents 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 comm unity notification system and clear guidelines for its implementation contributed to impact or injury to th e 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 sy stems, 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 sp ecify the responsibilities of response team members during a release. The Chlorine Institute (2000a) r ecommends 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 designate d 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 proce dures contained instructions for employee action during a release, they did not provide clear guida nce on when facility emergency response personnel respond to a release or when offsite community HAZMA T response is required. This lack of guidance explains the indecision among facility personnel r esponsible 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 t eam 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 requir es offsite community response. More definitive emergency response plan guidelines would ha ve 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 tim etables or schedules for either initial or annual employee refresher training in accordance with HAZWO PER requirements. The plan had no built-in audit procedures. Furthermore, it made no pr ovisions for drilling emergency response personnel on various levels of response. Interviews with f acility 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 em ergency 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 ade quacy 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 th e 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 si mulate an actual emergency; and full-scale drills test the response of the entire community. DPC Festus was not prepared for a major uncontr olled 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 re viewed annually, whenever the facilit y is modified, and whenever there are personnel or organizational changes. 

### 5.3.2.5 Emergency Re sponse Equipment The DPC emergency response plan did not have cl ear 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 emerge ncy 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 fille d with chlorine gas because of it s proximity to the release. One alternative could have been to store additional equipment at another location, possibly offsite. The Chlorine Institute (2001) states: “ All personne l required to wear respiratory protection equipment (such as SCBAs) should be trained a nd 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 equipmen t 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 document ation, 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 re lease 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 c oordinate 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 wo rk with local authorities on chemical emergency preparedness. The EPA RMP guidance document r ecommends that the facility also coordinate emergency response training and drills with local plan ning authorities, and offer them a copy of the plan.DPC Festus 05-30-03

64 Coordination between local emergenc y planning and response entities and DPC was insufficient to ensure that the emergency plan would provide for timely co mmunity 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, res ponse, 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 deve loping 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 commun ity emergency response plan. The LEPC, whichDPC 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 deficienci es 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 t esting with all participating local authorities (e.g., Jefferson County EMA; LEPC; Festus, Cr ystal City, and Jefferson County police and fire departments; HAZMAT unit; Jefferson Memorial Hospital; ambulance services).

• It had not been tested for such potential r esponses 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 colle ction of new data. Drills and exercises could have revealed or clarified planning and training weakn esses, 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 pa rties (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 notif y 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 emerge ncy 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, comm unity sirens or alert networks that immediately notify the exposed public are a better alternative. Ra dio 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 proce dure 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 reducedthe overall response and mitigation time; however, it is no substitute for prevention of the release it self through preventive maintenance, testing, and inspection to ensure that the ESD syst em 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 activiti es. 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 dete rmine which response activities need interagency coordination and which, if any, activities ar e 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 re sponse is necessary. Alternatively, for large chemical releases (as determined by the inci dent 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 immediat e 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 b ypass highway construction.DPC Festus 05-30-03

68 • The HAZMAT truck was redirected from the nor th command post to the south post, where State, County, and local authorities were c oordinating 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 aut horities 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 trai ning, drills, and actual incidents—are also critical to effective emergency response. ATSDR and the Federal Emergency Management Agen cy (FEMA) offer additional guidance specifically designed to assist communities develop evidence-base d 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 prac tices 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 th at 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, outsi de 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 planni ng 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 ne twork 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 sel ection, handling and storage, and continuous improvement. Article IV, Handling and Storage, specifies that the company have a program to promote facility integrity and provi sions for control of processes during emergencies. A key requirement of RDP and a condition of membersh ip in NACD is third-party verification of member RDP policies and procedures. Although DPC Enterpri ses 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 membersh ip information provided by NACD, only one DX Distribution Group company (DXI Distributors, Inc.) was an NACD member.DPC Festus 05-30-03

71 

## 6.0 Root and Contributing Causes
6.1 Root Causes
1. The DPC quality assurance (QA) management sy stem did not have adequate provisions to ensure that chlorine transfer hoses (CTH) met req uired 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 material s offers an explanation for installation of the inappropriate hose at DPC Festus. DPC relied on in formation from the supplier to verify that the chlorine transfer hose met required specificati ons; the lack of an internal QA management system, including verification of braid material, allo wed the incorrect hose to be installed and left in operation until it failed. 2. Branham Corporation, the CTH fabricator/d istributor, 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 ab sence of PMI testing and the inability to validate its own certification and shipping documents. 3. The DPC testing and inspection program di d 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 test ed from the activating device (button or detector)DPC Festus 05-30-03

72 through to verification that the valves actually cl osed. Inadequate testing and inspection of the ESD system probably led to undetected failures of th e 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 manuf acturers 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 ca used 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 cl osing 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 ineffici ent, which resulted in additional exposure to neighboring residents and businesses. Because of the catastrophic nature of the chlo rine release, personnel evacuated the facility immediately without simultaneously notif ying neighboring businesses and residents.DPC Festus 05-30-03

73 4. DPC emergency preparedness planning was deficient. Lack of clear guidelines and mechanisms for co mmunity notification (e.g., community sirens, alert network); inadequate designation of r esponsibilities 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 pos t-incident remediation resulted in DPC’s inadequate preparedness for a large uncontrolled release. 5. Jefferson County community emergency prep aredness 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 assuran ce 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 veri fy that the ESD valves will close to shut down the flow of chlorine. (2002-04-I-MO-R2)

• Revise the preventive maintenance and inspec tion program for the chlorine transfer system to address moisture-related corrosion. Evaluate and correct any problems associated with corrosion that could potentia lly 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-in cident 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 larg e uncontrolled release that could affect theDPC 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 comm ittee 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 fo r emergency response, considering likely response scenarios. (2002-04-I-MO-R7) 

### DX Distribution Group (corporate ow ner 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 in tegrity, 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 opera tions, revise your corporate safety managementtraining program on chlorine repackaging opera tions. Emphasize safety critical systems, including verification of safety system performance. (2002-04-I-MO-R9) 3. Communicate the findings and recommendations ofthis report to all DPC facilities. (2002-04-IMO-R10) 

### Branham Corporation Implement a materials verification procedure to im prove 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)DPC Festus 05-30-03

76 

### Jefferson County Emergency Ma nagement 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 Emerge ncy Response Commission Communicate the findings and recommendations of this report to local emergency planning committees (LEPC), emergency management agencies (EMA), a nd 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 Acc essories 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 emer gency shutdown [ESD] systems). (2002-04-I-MOR19) 3. Develop recommended practices for testing, in spection, 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 Distri butors (NAHAD)
1. Work with The Chlorine Institute and chlorine hose manufacturers, such as Crane-Resistoflex, to develop and implement a recommended practice re quiring continuous positiv e 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 Chem ical Distributors (NACD) Communicate the findings and recommendations of th is 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, 2003DPC 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, 20 02, 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 Wate r Distribution in a Chlorine Condensing System,” 25 th 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 th at 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 Cl 2 Æ 2 FeCl 3 [Eq A-1] The reaction product, ferric chloride (FeCl 3 ), 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 te mperature (e.g., chlo rine 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 mois ture/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 liqui d 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 dissolv es the protective layer of ferric chloride, but also forms an acid medium by reaction of chlorine with water (U pdyke, 1982). The chlorine-water reaction forms hypochlorous acid (HOCl) and hydrochloric acid (HCl):
Cl 2 + H 2 O 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” th e 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 equippe d with a moisture analyzer and an automatic regenerating dessicant dryer that uses a moisture-absor bing 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, insp ection of one of the emergency shutdown (ESD) valve actuators revealed liquid moisture trapped within the act uator mechanism. This moisture is likely to haveDPC 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 cl ogging 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 sy stem 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, pressur e 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 th e same standard. In the case of the August 14 release,DPC Festus 05-30-03

85 this information—along with the certificate of analys is for the shipment—provi des 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 bu ilding, a storage tank area, and an office building. The repackaging building houses the cleaning, preparati on, 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 build ing 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 build ing. 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 unloadi ng 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 forDPC 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) opening 5 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 chlori ne 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 sy stem piping ties into a common header located in the repackaging building. The header feeds a main suppl y 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 th e 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 d escribes the sequence of actions necessary to connect plant piping to the chlorine tank car. It specifies th at 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 unloadi ng 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 pi pe 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 facilita te 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 pressu re 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 Transpor tation (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. ow ned 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 Sta ndby 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 va lves 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 safe ty systems were verified, including the pressure relief valve and excess flow valves. DOT requires chlorine tank car pressure relief va lves 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 lining 9 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 Branha m Corporation to fabricate the Crane-Resistoflex chlorine transfer hose. The company placed its firs t order (for the Festus facility) with Branham for the Crane-Resistoflex CTH design 10 on July 24, 2000. The hose descrip tion used in this purchase order was of the old Monel-lined design (see Figure B-3). Br anham corrected the error because its arrangement with DPC was to fabricate Teflon-lined hoses. On July 25 th , Branham shipped to Festus the newly fabricated hose. All DPC hose descriptions on purchase orders to Br anham placed after July 24, 2000—including the March 18, 2002, order—stated “Monel-lined.” On a ll orders prior to March 18, Branham had supplied DPC with the correct Teflon-lined CTH design despit e 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 ho ses at the three tank car unloading st ations 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. 10 Tank 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 hos e 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 fo llowed 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 fabricationDPC 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 rec overing back-to-normal operations.

• Specific instructions for shutting down equipment and processes.

• Facility evacuation procedures, including a desi gnated meeting site outside the facility and a process to account for all employees after an evacuation.

• Emergency response equipment requirements and pr ocedures 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 redistri bution of the emergency response plan.DPC Festus 05-30-03

95 • Procedures for coordination of related activiti es with local emergency response and planning officials. The emergency response plan also needs to consider whether:

• Other nearby facilities may pose a hazar d 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 us ing 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 s hould 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

Chemical attack Mechanical

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 layerDPC 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 A ND GATE

OR GATE

ENDDPC Festus05-23-0398APPENDIX F: Causal Factors Diagram, Chlorine ReleaseMaterials testing /verification methodsnot usedShipping documents fromBranham indicate Hastelloywas sent to DPCChlorine monitor detectschlorine and sounds alarmTime: ~9:20 a.m.Moisture intrudes intochlorine systemValves do not close dueto corrosion buildupChlorine monitoringsystem initiates shutdownsequenceTime: 9:20 a.m.ESD system failsTime: 9:20 a.m.Wet chlorine reacts withsteel pipeExcess flow valve does notcloseTime: 9:20 a.mEmployees evacuatewithout isolating leakTime: 9:27 a.m.Release impactscommunityTime: 9:27 a.m.Chlorine release occursTime: 9:20 a.m.4/5 valves at rail rack donot close due to corrosionActuator torque LTA toclose valvesStainless-steel hoseincompatible withchlorine serviceBranham fabricated hose ofstainless-steelHose installedDate: 6/15/02Hose ruptured on 8/14/02Time: ~9:20 a.m.Stainless-steel hoseinstalled instead ofHastelloy; corrosion led toweakened structuralintegrityActual flow may have beenless than set pointHastelloy braid hoseidentical in appearance tostainless-steel hoseADPC acquires Festusfacility from JonesChemical Co.Date: 8/20/98Community notificationLTADPC emergencyresponse planLTASee column #7DPC QALTASupplier QALTAPlant manager pushesemergency shutdownbuttonTime;9:26 a.m.Mechanical integrity3214567891011Training and proceduresSee columns #10and #18DPC Festus05-23-0399A911 notifiedTime: 9:27 a.mR-7 (fire department)initiates evacuation ofBlue Fountain mobliehome parkTime: 9:37 a.mHAZMAT duty officerpagedTime: 10:45 a.m.HAZMAT truck at northcommand postNo lights or sirens onresponse vehiclesEmergency respondersscattered across countyTime: 11:15a.m.Full HAZMAT assembly atsouth command postTime: ~11:45 a.m.HAZMAT entry preparationResponders take timeto assembleJefferson Countyemergency responseplanningLTATime: 12:21 p.m.HAZMAT enters and shutsoff leak 2:54 after initialreportDate: 8/14/02DPC attempts onsitecleanupDPC remediation planLTADPC employees exposedto chlorineInadequate PPEInadequate execution1213141516171819HAZMAT volunteers seekpermission to leave jobsDPC emergecy responseplan LTAInadequateremediation planCAUSAL FACTORSCONTRIBUTING CAUSESLTA: less than adequate.