Case Study: BP Texas City Explosion 23 March 2005
When the Day Board Operator changed shifts in the central control room with the Night Board Operator shortly after 6:00 a.m., he received very little information on the state of the unit. The Day Board and Night Board Operators spoke to each other, but because the Night Board Operator was not the one who filled the tower, he provided few details about the night shift’s raffinate section startup activities other than what was written in the logbook (ERROR).
The Day Board Operator read the logbook (“ISOM: Brought in some raff to unit, to [fill] raff with.”) and interpreted the entry to mean that liquid was added only to the tower; the Day Board Operator, in post-incident testimony, said that he was unaware that the heat exchangers, the piping, and associated equipment had also been filled during the previous shift. The ISOM-experienced Day Supervisor, Supervisor A, arrived for his shift at approximately 7:15 a.m., more than an hour late, and did not conduct shift turnover with any night shift personnel (ERROR).
Beginning of the End – Day Shift Raffinate Tower Startup
On the morning of March 23, the raffinate tower startup began with a series of miscommunications. The early morning shift directors’ meeting discussed the raffinate startup, and Day Supervisor B, who lacked ISOM experience, was told that startup could not proceed because the storage tanks that received raffinate from the splitter tower were believed to be full. The Shift Director stated in post-incident interviews that the meeting ended with the understanding that the raffinate section would not be started. This decision was consistent with a March 22 storage tank area logbook entry that stated the heavy raffinate tank was filling up. The instruction to not start the raffinate section was not communicated to the ISOM operations personnel (ERROR).
Day Supervisor A told the operations crew that the raffinate section would be started. Because the startup procedure that should have provided information on the progress of the startup by the night shift was not filled out and did not provide instructions for a non-continual startup, the Day Board Operator had no precise information of what steps the night crew had completed and what the day shift was to do.
Day Supervisor A did not distribute or review the applicable startup procedure with the crew, despite being required to do so in the procedure (ERROR).
Startup resumed at 9:51 a.m. Even though the Day Board Operator did not have the benefit of a written procedure with the completed steps initialed to indicate the exact stage of the startup, raffinate circulation was restarted and feed introduced into the splitter tower, which already had a high liquid level.
The Day Board Operator, acting on what he believed were the unit’s verbal startup instructions and his understanding of the need to maintain a higher level in the tower to protect downstream equipment, closed the level control valve. However, the startup