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Bayer CropScience Pesticide Waste Tank Explosion

Overview

On August 28, 2008, at the Bayer CropScience facility in Institute, West Virginia, a runaway methomyl decomposition reaction inside the residue treater during methomyl unit restart caused a vessel rupture and fire. Two fatalities and eight injuries were reported. A large emergency response followed. The CSB final report identified deficiencies in process hazards analysis, pre-startup safety review, process safety information and training, and emergency planning and response.

Incident Snapshot

Field Value
Facility / Company Bayer CropScience, LP
Location Institute, West Virginia
Incident Date 2008-08-28
Investigation Status CSB final investigation report released at a public meeting in Institute, WV on 2011-01-20
Accident Type Chemical Manufacturing - Fire and Explosion Investigation
Final Report Release Date 2011-01-20

What Happened

  • On August 28, 2008, at about 10:25 p.m., two Bayer CropScience employees at the Institute, West Virginia, manufacturing facility were asked to investigate why pressure was unexpectedly increasing in the residue treater.
  • About 10 minutes later, as they approached the newly installed residue treater, it suddenly and violently ruptured.
  • Approximately 2,200 gallons of flammable solvents and toxic insecticide residues sprayed onto the road and into the unit and immediately erupted in flames.
  • The fire burned for more than 4 hours.
  • At approximately 4 a.m. on August 28, the board operator manually opened the residue treater feed control valve and began feeding flasher bottoms into the nearly empty vessel.
  • At 6:14 p.m., the outside operator started the recirculation pump as directed by the board operator.
  • At 10:21 p.m., the level was 51 percent when the recirculation flow suddenly dropped to zero.
  • At approximately 10:25 p.m., the residue treater high pressure alarm sounded at the work station.
  • At 10:33 p.m., a violent explosion rocked the control room.
  • At 10:45 p.m., Bayer activated its Emergency Operations Center (EOC).
  • At 11:19 p.m., Metro 9-1-1 announced a shelter-in-place for the immediate area surrounding the Bayer facility.
  • At about 11:34 p.m., the KPEPC activated the County Emergency Alert System, which in turn initiated a shelter-in-place for the areas west of Charleston to Putnam County line.
  • At 12:34 a.m., Bayer notified the National Response Center.
  • At 2:05 a.m., Kanawha Putnam EOC declared the area west of Charleston safe to re-enter and canceled the shelter-in-place action.

Facility and Process Context

  • The Institute facility is located 9 miles west of Charleston, West Virginia, and is bordered on the north by Route 25 and Interstate 64, on the east by the West Virginia State University, and along the south by the Kanawha River.
  • In August 2008, the 460-acre, multi-tenant Institute Manufacturing Industrial Park employed approximately 645 workers.
  • Bayer owns and operates nine production and utility units at the Institute facility.
  • The Methomyl-Larvin unit occupied the West Carbamoylation Complex.
  • The East Carbamoylation Complex includes the MIC and Phosgene production unit and the Aldicarb and Carbaryl units.
  • The Institute facility is the only facility in the United States that stores and uses large quantities of methyl isocyanate (MIC).
  • The Methomyl-Larvin unit and other units in the facility are subject to the RMP rule.
  • The unit contained two listed toxic chemicals, methyl isocyanate (TQ = 10,000 pounds) and methyl mercaptan (TQ = 5,000 pounds).
  • The MIC day tank was a 6,700-gallon-capacity stainless steel pressure vessel.
  • Liquid MIC was transferred from the MIC production unit about 2,500 feet through an insulated piping system to an aboveground pressure vessel called a day tank located adjacent to the Methomyl-Larvin production unit.

Consequences

  • Fatalities: Two killed. One employee died at the scene and the second died 41 days later in a burn center.
  • Injuries: Eight injured; six volunteer firefighters and two contractors were treated for possible toxic chemical exposure. First-responders working near the explosion and fire did not wear adequate respiratory protection and were not decontaminated.
  • Environmental release: More than 2,000 gallons of toxic and flammable liquid was expelled from the residue treater, ruptured piping, and other equipment, most of which burned in the ensuing fire. Trace amounts of methomyl were found in swipe samples from equipment in the vicinity of the explosion; the specific quantities of un-decomposed or unburned methomyl or other toxic chemicals that might have escaped into the atmosphere were indeterminate.
  • Facility damage: The 5,700-pound residue treater ripped out piping, electrical conduit, and a structural steel support column as it split apart and careened into the Methomyl-Larvin production unit structure. The blast overpressure moderately damaged the unit control building and other nearby structures. The explosion destroyed nearby pumps, heat exchangers, and electrical switchgear.
  • Operational impact: The incident occurred during the restart of the methomyl unit after an extended outage. The fire burned for more than 4 hours. Roads near the facility and Interstate 64 were closed, traffic was disrupted for hours, and more than 40,000 residents were advised to shelter-in-place for more than three hours.

Key Findings

Immediate Causes

  • Bayer did not apply standard Pre-startup Safety Review (PSSR) and turnover practices to the methomyl control system redesign project.
  • Operations personnel were inadequately trained to operate the methomyl unit with the new distributed control system (DCS).
  • Malfunctioning equipment and the inadequate DCS checkout prevented the operators from achieving correct operating conditions in the crystallizers and solvent recovery equipment.
  • The out-of-specification methomyl-solvent mixture was fed to the residue treater before the residue treater was pre-filled with solvent and heated to the minimum safe operating temperature.
  • The incoming process stream normally generated an exothermic decomposition reaction, but methomyl that had not crystallized due to equipment problems greatly increased the methomyl concentration in the residue treater, which led to a runaway reaction that overwhelmed the relief system and over-pressurized the residue treater.

Contributing Factors

  • deviation from the written start-up procedures
  • bypassing critical safety devices intended to prevent such a condition
  • an inadequate pre-startup safety review
  • inadequate operator training on the newly installed control system
  • unevaluated temporary changes
  • malfunctioning or missing equipment
  • misaligned valves
  • insufficient technical expertise available in the control room during the restart
  • poor communications during the emergency between the Bayer CropScience incident command and the local emergency response agency
  • the only air monitors suitably placed near the unit to detect toxic chemicals were not operational at the time of the incident
  • The PHA team failed to validate critical assumptions used in their analyses
  • The PHA did not adequately incorporate the process safety information used as a basis for the assumptions and conclusions
  • The PHA team concluded that a high residue concentration in the flasher feed was an operations issue having “no consequence”
  • The residue treater layers of protection to prevent a runaway reaction were inadequate.
  • Previous PHA action items were not closed in a timely manner, including operator training and control of process safeguards.
  • The methomyl unit SOP was overly complex and not reviewed and approved prior to the methomyl unit startup.
  • The SOP did not include flasher tails methomyl concentration testing as required by the original construction process safety information package.
  • The PSSR did not include a formal process involving multiple disciplines.
  • The PSSR did not verify the completion of modifications in the field, including the Methomyl-Larvin unit toxic gas monitoring system was not in service, project engineers did not verify the functionality of critical DCS control and indication circuits, and operating equipment and instruments were not installed before the restart.
  • Equipment checkouts as required by the pre-startup safety review were incomplete.
  • Control system training was inadequate.
  • The operators were not formally trained on the methomyl DCS and were not familiar with some of the changed units of measure used on the DCS displays.
  • Methomyl unit board operators were not provided with computer screen displays to effectively operate all assigned process and utility systems.
  • Multiple operational problems diverted the staff’s attention.
  • Operations personnel incorrectly assumed that methomyl was not being produced in the reactor even though the flasher feed sample lab results were available.
  • Operators and technical staff did not troubleshoot why the centrifuges did not contain methomyl cake.
  • Several required SOP steps were not completed during the methomyl unit startup.
  • Management did not strictly enforce the safety matrix control policies.
  • Bypassing the safety interlocks on the residue treater flasher bottoms feed valve allowed the empty residue treater to be filled with concentrated methomyl.
  • Oxime system startup problems diverted operators’ attention, resulting in poor communication between methomyl board operators at shift change.
  • The residue treater relief system design basis was invalidated during the methomyl unit startup.
  • The design basis assumed that the safety interlocks were active, but the interlocks were bypassed.
  • The resident treater relief system design basis relied on administrative controls such as sample collection and analysis to prevent overcharging methomyl, but these controls were either incomplete or not implemented before startup.
  • A runaway methomyl decomposition reaction inside the residue treater overwhelmed the vent system and caused the vessel to violently explode.
  • The blast blanket design basis did not consider an impact of a large object moving at high velocity.
  • The Bayer onsite emergency response did not conform to the unified command structure contained in the National Incident Management System (NIMS) protocols.
  • Bayer did not assign a Public Information Officer (PIO) to directly communicate with the Kanawha Putnam EOC and Metro 9-1-1.
  • Unknown to Bayer emergency personnel, the Methomyl-Larvin unit air monitor system that they relied on to determine and report airborne concentrations of possible toxic chemicals was not in service the night of the incident.
  • Bayer had only two distant fenceline air monitors to determine the extent of chemical contaminants traveling off site.
  • Although the Bayer IC recommended a shelter-in-place, the Bayer EOC did not notify Metro 9-1-1.
  • Bayer discontinued hot zone decontamination activities before all emergency responders were able to clean their safety gear.
  • The overloaded telephone system prevented Bayer from promptly notifying the Metro 9-1-1 center of the incident.
  • County emergency responders established three separate EOCs in response to the incident, which resulted in duplication of effort, poor communication, and conflicting control.
  • First-responders working near the explosion and fire did not wear adequate respiratory protection and were not decontaminated.
  • The Kanawha Putnam Emergency Management Plan does not adequately address emergency response personnel responsibilities and communications between the facility IC and outside emergency response organizations when a facility owner is responsible for incident command during an on-site emergency involving hazardous chemicals.
  • MIC air monitoring devices in the Methomyl-Larvin unit were not functioning at the time of the incident, preventing the accurate measurement of any MIC release from piping or equipment that might have resulted from the explosion and fires.
  • Two fenceline monitors located hundreds of feet from the incident location were ineffective for detecting toxic chemicals that might be released into the atmosphere either from process equipment leaks or spills, or combustion products from a major fire.
  • Both OSHA and EPA had conducted process safety related audits and inspections at the Bayer facility prior to the incident in August 2008, however, the inspections did not detect or correct all the serious, longstanding process safety problems that were revealed by investigations conducted after the incident.

Organizational and Systemic Factors

  • first-line supervisor positions in each operating unit were eliminated and self-directed, or self-empowered work teams were implemented
  • a single Industrial Park Site Shift Leader was responsible for all facility operations
  • the Technical Advisor does not have the strong work-checking or “looking over the shoulder” function of a historical first-line supervisor or foreman
  • the reorganization resulted in only one Technical Advisor assigned to the entire Methomyl-Larvin unit who worked the day shift
  • the night shift did not have a Technical Advisor on duty
  • management did not require any methomyl operator to use the time on the console to learn and practice operating the methomyl unit
  • management concluded that comprehensive formal training and practice using the new DCS on the methomyl process was unnecessary
  • management was so far removed from the process operation that they were unaware that the operators seldom used the SOP and some bypassed the critical safety interlocks
  • the self-directed work team ultimately decided to start the methomyl unit even though the control system and some equipment were not ready and the SOP was not up-to-date
  • the PSSR team did not directly involve operators or other subject matter specialists
  • problems with action item tracking and closure continued
  • the 2007 facilitated self assessment found that action tracking deficiencies identified in previous corporate PSM audits and facilitated self assessments remained unaddressed
  • management did not effectively review the available computer records of [SOP] deviations and intervene to prevent future deviations
  • management did not enforce procedural compliance or proper application of MOC to ensure SOP errors were corrected
  • management did not enforce compliance with SOP
  • management did not enforce policy for control of bypassing safety interlocks
  • management did not resolve the difference between operating practice and the standard operating procedures
  • management did not enforce management of change process
  • PHA training and execution were inadequate
  • PHA training and execution led to these deficiencies
  • The 2005 PHA depended too heavily on the existing PHA rather than providing in depth analysis
  • The PHA team gave too much credit to the automatic controls (interlocks) being in place
  • The 1994 PHA team identified the loss of containment event but did not recommend changes to prevent the event
  • The 1994 PHA team identified the loss of containment event but did not account actual practice of bypassing interlocks
  • The MOC process for the 2008 DCS project did not perform a PHA that considered the potential to bypass interlocks
  • The capital project did not perform human factors analysis
  • PSSR did not identify these deficiencies
  • PSSR did not verify equipment in field was ready for start-up
  • Project process did not check all critical instrument settings before handover
  • Mechanical integrity program did not identify the problem
  • Operations training on process hazards did not train the operators that unreacted MSAO also decomposed and could lead to a runaway reaction
  • Operators were accustomed to normal start-up (with material left in the residue treater from the end of the previous run)
  • Operators were used to running the residue treater in batch mode rather than continuous (procedures are written to run in continuous mode)
  • Operators sometimes deviated from SOP during residue treater start-up
  • Operator perception that the sampling was to verify quality of material going to fuel use rather than for safe operating limits
  • The MIBK / hexane column was not operating properly
  • There was MIBK in the recycle hexane
  • Data entry, response, and feedback were all different from previous control system
  • Units of measure were different from previous control system, and no conversion table was supplied to operations
  • Ability to focus on specific pieces of equipment was lost in the conversion
  • Inadequate training techniques on the new control system, and inadequate training time on the new control system

Failed Safeguards or Barrier Breakdowns

  • minimum temperature interlock
  • maximum pressure interlock
  • minimum recirculation loop flow interlock
  • safety matrix interlocks
  • PSSR checklist
  • MIC air monitoring system
  • fenceline air monitors
  • relief system
  • emergency vent system
  • blast blanket
  • firewater monitors
  • laboratory sampling of flasher bottoms before or during residue treater operation
  • shift change communications
  • operating procedures
  • action tracking system
  • The PHA team did not validate the assumptions in the PHA including accuracy of the SOP, conformance to the SOP, and control of process safeguards.
  • The PSSR did not include a formal process involving multiple disciplines.
  • The PSSR did not verify the completion of modifications in the field.
  • Equipment checkouts as required by the pre-startup safety review were incomplete.
  • Control system training was inadequate.
  • The Methomyl-Larvin unit toxic gas monitoring system was not in service.
  • Project engineers did not verify the functionality of critical DCS control and indication circuits.
  • Operating equipment and instruments were not installed before the restart.
  • Methomyl unit board operators were not provided with computer screen displays to effectively operate all assigned process and utility systems.
  • The new Siemens operating system was not calibrated.
  • The residue treater was not pre-filled with solvent.
  • The solvent was not circulated and heated to the minimum operating temperature.
  • The 7 a.m. daily residue treater liquid sample was not collected and analyzed for methomyl concentration.
  • Bypassing the safety interlocks on the residue treater flasher bottoms feed valve allowed the empty residue treater to be filled with concentrated methomyl.
  • The residue treater relief system design basis was invalidated during the methomyl unit startup.
  • The design basis assumed that the safety interlocks were active, but the interlocks were bypassed.
  • The resident treater relief system design basis relied on administrative controls such as sample collection and analysis to prevent overcharging methomyl, but these controls were either incomplete or not implemented before startup.
  • The blast blanket design basis did not consider an impact of a large object moving at high velocity.
  • The blast mat is assumed to act as a rigid plate, which transmitted all forces directly into the frame.
  • The frame assembly design records address only the capacity of the frame to support the deadweight of the installed mats, plus wind loads.
  • The MIC day tank air monitors and the Methomyl-Larvin unit air monitor system were not functioning at the time of the incident.
  • The two working fenceline monitors were not capable of detecting chemicals such as methomyl and MIBK.
  • Bayer did not assign a Public Information Officer (PIO) to directly communicate with the Kanawha Putnam EOC and Metro 9-1-1.
  • Bayer did not share relevant information with Metro 9-1-1.
  • The overloaded telephone system prevented Bayer from promptly notifying the Metro 9-1-1 center of the incident.
  • County emergency responders established three separate EOCs in response to the incident.
  • First-responders working near the explosion and fire did not wear adequate respiratory protection and were not decontaminated.

Recommendations

  1. 2008-08-I-WV-R1 | Recipient: Bayer CropScience – Research Triangle Park, NC | Status: Not specified | Revise the corporate PHA policies and procedures to require validation of all PHA assumptions, coverage of all phases of operation and special topics, and training of all PHA facilitators. Update all PHAs to conform to the revised procedures.
  2. 2008-08-I-WV-R2 | Recipient: Bayer CropScience - Institute, West Virginia | Status: Not specified | Review and revise all Bayer production unit standard operating procedures to ensure they address all operating modes, are accurate, and approved.
  3. 2008-08-I-WV-R3 | Recipient: Bayer CropScience - Institute, West Virginia | Status: Not specified | Ensure that all facility fire brigade members are trained in the National Incident Management System, consistent with municipal and state emergency response agencies.
  4. 2008-08-I-WV-R4 | Recipient: Bayer CropScience - Institute, West Virginia | Status: Not specified | Evaluate the fenceline air monitor program against applicable requirements and Bayer corporate policies, and upgrade and install air monitoring devices as necessary.
  5. 2008-08-I-WV-R5 | Recipient: Bayer CropScience - Institute, West Virginia | Status: Not specified | Commission an independent human factors and ergonomics study of all Institute site PSM/RMP covered process control rooms and implement a plan to resolve all recommendations.
  6. 2008-08-I-WV-R6 | Recipient: Director of the Kanawha-Charleston Health Department | Status: Not specified | Establish a Hazardous Chemical Release Prevention Program to enhance prevention and response for accidental releases of highly hazardous chemicals.
  7. 2008-08-I-WV-R7 | Recipient: Secretary of West Virginia Department of Health and Human Services and the West Virginia Department of Environmental Protection | Status: Not specified | Work with the Director of the Kanawha-Charleston Health Department to ensure planning, fee collection, and implementation of the Hazardous Chemical Release Prevention Program.
  8. 2008-08-I-WV-R8 | Recipient: Kanawha-Putnam Emergency Planning Committee | Status: Not specified | Revise the Kanawha Putnam County Emergency Response Plan and Annexes to address facility emergency response and Incident Command when provided by the facility owner.
  9. 2008-08-I-WV-R9 | Recipient: West Virginia State Fire Commission | Status: Not specified | Revise the fire department inspection matrix to require inspectors to examine and identify the status of National Incident Management System fire department personnel training.
  10. 2008-08-I-WV-R10 | Recipient: Occupational Safety and Health Administration | Status: Not specified | Conduct a comprehensive Process Safety Management inspection of the Bayer Institute site and coordinate with EPA as appropriate.
  11. 2008-08-I-WV-R11 | Recipient: Occupational Safety and Health Administration | Status: Not specified | Revise the Chemical National Emphasis Program and targeting criteria to expand coverage, include establishments with prior PSM citation closure certifications, and require inspections to examine compliance with previously cited items.
  12. 2008-08-I-WV-R12 | Recipient: Environmental Protection Agency | Status: Not specified | Conduct a comprehensive Risk Management Program inspection of the Bayer Institute site and coordinate with OSHA as appropriate.

Key Engineering Lessons

  • Pre-startup safety review and turnover practices must verify that redesigned control systems, instruments, and operating equipment are installed, tested, calibrated, and ready before restart.
  • Operating procedures must be accurate, approved, and updated for the actual control system and all operating modes, including startup and turnaround restart.
  • Bypassed interlocks and other nullified safeguards must be explicitly considered in process hazard analyses and management of change.
  • Relief system design basis must account for the actual startup configuration, including the possibility that interlocks are bypassed and administrative controls are incomplete or not implemented.
  • Human factors issues such as control room interface, operator familiarity with changed units of measure, and fatigue can materially affect safe startup of a complex process.
  • Air monitoring and perimeter monitoring must be effective and operational when hazardous chemicals may be released, including during fire conditions.
  • Emergency response communications and incident command arrangements must be clear enough to support unified command, timely public notification, and responder decontamination.

Source Notes

  • Priority 1 final report used as the authoritative source for incident causation, findings, and recommendations.
  • Priority 2 and 3 recommendation status summaries were used only to confirm recommendation text and status changes where relevant.
  • Priority 4 supporting documents were used only to supplement event sequence, facility context, and detailed findings when consistent with the final report.
  • Where source documents differed in wording, the higher-priority final report terminology was preserved.

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