How a Startup Error Led to a Fire that Injured 23 Workers at a Texas Chemical Plant
The U.S. Chemical Safety and Hazard Investigation Board (CSB) released its final investigation report and incident animation for the 2018 fire that injured 23 workers at the Kuraray America, Inc. EVAL plant in Pasadena, Texas. The report identifies 17 safety issues that contributed to the incident and provides 12 recommendations to prevent similar incidents in the future.
What happened?
The incident occurred on May 19, 2018, during the startup of a chemical reactor system following a scheduled maintenance shutdown – also referred to as a turnaround. High pressure conditions developed inside the reactor and activated the reactor’s emergency pressure relief system, discharging flammable ethylene vapor through piping into an area where a number of contractors were working. Over 2,300 pounds of ethylene were released in approximately three minutes. The work being done by the nearby contractors included welding, which most likely ignited the flammable vapor. Among the 23 workers injured during the incident, two were life-flighted from the facility, one of whom remained in critical condition for several days because of burn injuries. As many as 19 others were transported to the hospital by emergency responders for various injuries.
What caused the incident?
The CSB determined that the cause of the incident was Kuraray’s emergency pressure relief system design that discharged flammable ethylene vapor from the reactor through horizontally aimed piping into the air in an area near workers. If Kuraray’s emergency pressure relief system had been designed to discharge the vapor to a safe location, the flammable ethylene gas should not have harmed any workers.
CSB Chairperson Steve Owens said, “Kuraray could have prevented the injuries to these workers by ensuring that the flammable ethylene gas discharged from its system was directed to a safe location. Kuraray also should have evacuated these workers from the area when the reactor’s high-pressure alarm sounded, since it was signaling a serious problem with the reactor.”
The CSB’s investigation report details a chain of process safety management failures that led to the build-up of excessive pressure inside the reactor. The emergency pressure relief system discharge design is just one of the 17 safety issues identified by the CSB in the report. The additional 16 safety issues are:
| Safety Issue | Description |
|---|---|
| Presence of Nonessential Workers During Startup and Upset Conditions | Kuraray did not have a policy or procedure to ensure that only essential personnel were present in the process area during startup and upset conditions. |
| Hazardous Location Recognized and Generally Accepted Good Engineering Practices | Kuraray did not follow recognized and generally accepted good engineering practices (RAGAGEP) for hazardous locations, such as the National Electrical Code (NEC), which requires electrical equipment to be suitable for the location and to prevent ignition of flammable vapors. |
| Process Hazards Analysis Safeguards | Kuraray did not identify or implement adequate safeguards to prevent or mitigate the consequences of a flammable vapor release from the emergency pressure relief system. |
| Process Hazard Analysis Recommendations | Kuraray did not adequately address or implement the recommendations from its process hazard analysis (PHA), such as installing rupture disks on the emergency pressure relief system or relocating the emergency pressure relief system discharge piping. |
| Warning Signs | Kuraray did not post warning signs or barricades to alert workers of the potential hazards of the emergency pressure relief system discharge piping. |
| Equipment Design | Kuraray did not design the emergency pressure relief system discharge piping to minimize the potential for flammable vapor accumulation or ignition. |
| Operating Procedures | Kuraray did not have clear, accurate, and consistent operating procedures for the startup of the reactor system. |
| Operator Training | Kuraray did not provide adequate operator training on the startup of the reactor system, the emergency pressure relief system, and the response to abnormal operating conditions. |
| Abnormal Operating Conditions | Kuraray did not have a formal process to identify, evaluate, and manage abnormal operating conditions, such as high pressure in the reactor. |
| Safety Interlock Disabling | Kuraray did not have a policy or procedure to control the disabling of safety interlocks, such as the high-pressure trip on the reactor. |
| Alarm Management | Kuraray did not have an effective alarm management system to ensure that critical alarms, such as the high-pressure alarm on the reactor, were properly configured, prioritized, and responded to. |
| Process Alarm Response | Kuraray did not have a clear and consistent process alarm response procedure or training for operators. |
| Safe Operating Limits | Kuraray did not establish or communicate safe operating limits for the reactor system, such as the maximum allowable pressure. |
| Environmental Permit Limits | Kuraray did not comply with its environmental permit limits for the emergency pressure relief system, which required the use of a flare to combust the flammable vapors. |
| Safety Management System Self-Assessment Audits | Kuraray did not conduct effective safety management system self-assessment audits to identify and correct gaps in its process safety performance. |
What can be done to prevent similar incidents?
The CSB issued 12 recommendations to Kuraray America to address the safety issues identified in the report. The recommendations include:
- Developing an emergency pressure relief system design standard to ensure discharge to safe locations
- Developing and implementing a policy and procedure to ensure that only essential personnel are present in the process area during startup and upset conditions
- Following RAGAGEP for hazardous locations, such as the NEC
- Conducting a comprehensive PHA of the emergency pressure relief system and implementing the recommendations
- Posting warning signs or barricades to alert workers of the potential hazards of the emergency pressure relief system discharge piping
- Reviewing and revising the operating procedures for the startup of the reactor system
- Providing adequate operator training on the startup of the reactor system, the emergency pressure relief system, and the response to abnormal operating conditions
- Developing and implementing a formal process to identify, evaluate, and manage abnormal operating conditions
- Developing and implementing a policy and procedure to control the disabling of safety interlocks
- Developing and implementing an effective alarm management system
- Establishing and communicating safe operating limits for the reactor system
- Complying with the environmental permit limits for the emergency pressure relief system
The CSB also issued two recommendations to the American Chemistry Council (ACC) and the American Institute of Chemical Engineers’ Center for Chemical Process Safety (CCPS) to develop and disseminate guidance on emergency pressure relief system design and management.
The CSB is an independent federal agency that investigates major chemical incidents and issues recommendations to improve chemical safety. The CSB’s final report and incident animation for the Kuraray America investigation can be accessed at CSB Releases Final Report and Incident Animation for Kuraray Investigation.
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