Case Study: BP Texas City Explosion 23 March 2005
Manager and Process Safety Manager, were required (and thus expected to know of its existence and when it had to be accomplished) to sign off on the PSSR checklists and authorize the startup. However, none of the PSSR procedural steps were undertaken for the ISOM startup (ERROR).
Startup Instrumentation and Equipment Status
During pre-startup equipment checks, key splitter tower instrumentation and equipment were identified as malfunctioning but were not repaired. During the recently concluded ISOM maintenance period, operations personnel reported to supervisors that the splitter level transmitter and level sight glass needed repair (this equipment could not be repaired when the unit was operating since the isolation valves leaked). The level transmitter was not repaired because BP supervisors determined that there was too little time to complete the job in the existing turnaround schedule.
Both during unit shutdown and the equipment checks in the days preceding raffinate splitter startup, operations personnel found that a pressure control valve was inoperable on February 26 and March 22, 2005. The malfunctioning control valve was reported to a frontline supervisor; however, no work order was written and no repairs were made prior to startup. This same frontline supervisor signed off on the startup procedure that all control valves had been tested and were operational prior to startup (ERROR).
A functionality check of all alarms and instruments was also required prior to startup, but these checks were not completed (ERROR). On March 22, 2005, instrument technicians had begun checking the critical alarms when a supervisor told them that the unit was starting up and there was no time for additional checks. While some alarms were tested, most were not prior to startup. The supervisor, however, initialed on the startup procedure that those checks had been completed (ERROR).
Other key safety preparations listed in the startup procedures were omitted or ineffectively carried out (ERROR). BP guidelines state that unit startup requires a thorough review of startup procedures by operators and supervisors; however, this review was not performed (ERROR). The procedure also called for adequate staffing for the startup and that any unsafe conditions be corrected. Both of these steps were initialed as being completed by a unit trainee at the direction of his supervisor (judgment calls clearly, but there is no record of anyone even evaluating this) (ERROR).
March Toward Disaster – Initial Tower Filling and Shutdown