Caribbean Petroleum Explosion Case Study

Caribbean Petroleum Explosion Case Study

Q.A. Baker, J.K. Thomas, D.R. Malik and M.T. Edel

Baker Engineering and Risk Consultants

3330 Oakwell Court, Suite 100

San Antonio, TX  78218-3024

(210) 824-5960

QBaker@BakerRisk.com

A vapor cloud explosion (VCE) occurred at the Caribbean Petroleum site in Bayamón, Puerto Rico on October 23, 2009 shortly after midnight.  An above-ground gasoline storage tank (Tank 409) was being loaded from a cargo ship shortly before the incident.  Overfilling of Tank 409 resulted in gasoline discharge through elevated tank vents and the creation of a very large vapor-mist cloud, which extended off the plant site into surrounding areas covered with heavy vegetation.  Approximately 5,000 barrels (210,000 gallons, 790,000 liters) of gasoline were released, creating a cloud with a footprint of roughly 3x10⁶ ft² (70 acres, 0.3 km²).  The over-fill was halted roughly 10 minutes prior to the VCE.  The cloud was ignited at an electrical equipment enclosure outside the electrically classified area.  The resulting VCE caused blast damage to both on-site and off-site structures.  Fires were ignited in a number of other storage tanks within the tank farm, which burned for several days.

Based on comparisons with the damage observed by the authors both on- and off-site, it was concluded that the VCE preceded as a deflagration, with vegetation located outside of the tank farm representing most of the congestion responsible for the VCE.  The flammable cloud did not reach the congestion associated with the adjacent decommissioned refinery process units; these congested areas therefore did not participate in the VCE.  The tank farm itself is an area of relatively low congestion.  Contrary to some reports in the literature, which appear to have focused primarily on individual damage indicators within the vapor cloud, the results of this investigation indicated that the VCE did not precede as a detonation (i.e., a deflagration-to-detonation transition did not occur).  Additionally, contrary to the findings of some of the other investigations of this incident, it was concluded that the flame did not propagate through the east-west sewers.

This paper will present key findings from the investigation, the basis for these findings, and the main lessons learned from this incident.