Examples of incomplete data in CSB report, disclosed by MES

• ? told lead operator extruder had been run with purge material
• ? scheduled restart for March 12
• ? raised extruder temperature to 315∫C
• ? decided to close PCT without level detector
• ? called Maintenance ? to assist with extruder problem
• ? decided to divert process flow from PCT to RKP
• ? observed small fire in extruder and what did they see
• ? ignited residual purging material ?
• ? ? did what about fire in extruder
• ? observed vapor leak from RKP cover and what did they see
• ? left instructions for night shift to empty PCT and RKP of polymer
• ? purged extruder with purge material to clean screws
• ? extinguished remaining fire
• ? decided to not do recommended HAZOP after drawings finalized
• ? designated HAZOPS team for safety analyses of facility
• ? designated HAZOPS methodology for facility safety analysis
• ? observed thermal degradation in product performance tests
• ? tested unsuccessful alternative PCT level indicators
• ? isolated hot oil system to stop flow from tubing break
• ? recognized PCT was too small after overfilling
• ? repaired PCT relief valve fouled with polymer
• ? repaired PCT relief valve fouled with polymer (2^nd time)
• ? repaired PCT relief valve fouled with polymer (third time)
• ? ignited hot oil vapor cloud
• ? submitted engineering request to redesign system
• ? shut down Amodel unit to repair equipment in extruder
• ? mechanical problem delayed startup of unit for 4 ? hours

Examples of questions raised by MES

• Why didn't solvent clean out ash in extruder?
• Timing of fire/solvent shutoff/fire out?
• Was hot oil involved with PCT pressure rise?
• Why did workers have to position themselves in harms way to remove the head?
• Why did Maintenance Tech remove bolts in sequence he did, and would another sequence have changed the outcome?
• Need to confirm that hot oil continued flowing to heat inlet line to PCT after shutdown
• before and after head blew off - did that contribute to heading of contents?
• Why didn't HAZOP recommendation successfully control hazard? (Methodological problem)
• Why wasn't unsuccessful recommendation remedied when experience showed it was unsuccessful? (system problem)
• Why did Operators position selves with Maintenance Technician at head of PCT (if they did)
• What exactly created internal pressure -what were roles of hot oil, overfilling, and decomposition of stored material in PCT
• What ignited fire in extruder? Why did it spread
• Who told whom what and why about pre-run?
• What was data and rationale for this decision? Who made it?
• Find out what procedure is to learn from incidents ≠system breakdown or people problem?
• Find out why air could get into the extruder, providing oxygen for fire??
• What was the impact trauma that killed 2 workers - tank cover or plastic from inside tank?