Refinery Explosion and Fire Caused by Non-Functioning Computerized Level Monitoring System

Event Year: 2009 Reliability: Confirmed
Country: United States
Industry Type: Petroleum

A large vapor cloud ignited at the Caribbean Petroleum facility near San Juan Puerto Rico.  The explosion damaged homes and businesses over a mile from the facility.  At the time of the incident a tank was being filled with gasoline from a ship docked in San Juan harbor.  Investigators have determined that a likely scenario leading to the release was an accidental overfilling of the tank.  Gasoline spilled without being detected.  The Chemical Safety Board found that on the evening of the incident, the liquid level in the tank could not be determined because the facility’s computerized level monitoring system was not fully operational.  In order to monitor the level in the tank, operators used a mechanical gauge on the tank’s exterior wall.  Therefore, as the gasoline level in the tank rose and eventually overflowed, employees in the facility’s control room were unaware of the emergency.


Homes and businesses were damaged as a result of the blast.  Damage extended over a mile away from the facility.