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Incident Description
On March 23, 2005, there was a massive explosion at the BP America Texas City refinery which killed 15 workers and injured about 100 others. Although investigations by BP and the U.S. Chemical Safety Board (CSB) are still on-going, there have been key factors that have already been identified as possibly contributing to the magnitude of the incident. We want to communicate what has been made public to date and use the information as a learning opportunity for us to review our facilities and risk assessments.
What Went Wrong    (Most of this section is taken from CSB news releases)
•        Vents to atmosphere: Witnesses described the release of hydrocarbon liquid and vapor from an approximately 100-foot tall atmospheric vent stack. They observed this liquid and vapor falling toward the ground seconds before a powerful explosion. The atmospheric vent stack was connected to pressure relief devices in the Isomerization unit via a blowdown drum.
•        Location of trailers & temporary buildings: The placement of trailers in close proximity to an operating refinery unit is one factor that investigators will be focusing on. The trailers were 100-150 feet away from the blowdown drum when a geyser-like release of flammable hydrocarbons occurred.  The trailers reportedly were not associated with the Isomerization Unit.
•        Vapor Cloud Explosions: The trailers suffered severe damage. The debris pattern is reportedly indicative of a multiple vapor cloud explosion. Investigators are also looking into the possibility of an explosion underneath a trailer which may not have had skirting around the base. A lack of skirting might have allowed flammable vapors to travel into the very confined area under a trailer.
•        Vehicles in facility: In the area of debris, investigators found the demolished remnants of approximately 6 to 10 trailers and about 30 cars and trucks. It is unknown how many vehicles might have been running when the vapor cloud was released from the vent stack. A diesel pick-up truck was described by eyewitnesses as over-revving moments before the explosion. Vehicles were reportedly located within 25 yards of the vent stack.
•        Simultaneous Operations (SIMOPS): The unit where the release occurred was apparently being started up after a maintenance turnaround. Personnel were said to be having a meeting in a near-by trailer during the time of the unit start-up.
Preliminary Recommendations for CVX Facilities
Location of trailers& temporary buildings / Vapor Cloud Explosions:
•        Review the location/placement of trailers and temporary buildings using the methodology in API RP752 and the CT Fire Protection Manual. US PSM facilities will have already done facility siting studies that can be used as a starting point.
•        Treat temporarily-occupied buildings the same as permanent buildings. If we would not place a permanent building in a location without additional protection – we should not place temporary buildings there without appropriate risk reduction measures (blast walls, blast resistant trailers, etc.) either. There are temporary buildings that are designed for blast resistance if needed.
•        Review all temporary buildings and ensure that skirting is in place around the base.
Vents to atmosphere / Vehicles in facility / Simultaneous Operations (SIMOPS):
•        Identify all PSV’s that vent to atmosphere in your facility and review the risk assessments to ensure that potential release scenarios have been considered and appropriate safeguards are in place.
•        Conduct a SIMOPS review prior to special operations (start-up, shutdown, etc.) to determine whether other operations should be halted until start-up is complete. Examples could include hot work, vehicle traffic, maintenance, and additional personnel.
For additional information on related facility siting and/or fire protection guidelines, please contact the ETC Fire & Process Safety Team, the ETC Process Risk Team, or refer to the CT BEST Fire Protection Manual.
Prepared by the ETC Fire & Process Safety Team – Bruce Hartman   510-242-4204