CSB investigating massive tank fire (11/24)
At 12:23 a.m. on October 23, a large vapor cloud ignited at the Caribbean Petroleum facility near San Juan, Puerto Rico. The blast damaged homes and businesses over a mile from the facility. Investigators from the U.S. Chemical Safety Board arrived in Puerto Rico that evening. Over the past few weeks the five-person investigation team has conducted numerous interviews, requested hundreds of pages of documents and catalogued key pieces of evidence.
CSB Board Member William Wright said, “The CSB will conduct a thorough and comprehensive investigation of this accident; our team will uncover exactly what events led to an explosion of this magnitude. Our goal is to determine not only what happened, but why it happened.”
Caribbean Petroleum is a significant petroleum products supplier for Puerto Rico. The facility includes a tank farm and refinery that was shutdown in 2000. Prior to October 23 the tank farm stored gasoline, diesel fuel, jet fuel, and fuel oil in approximately 30 operational aboveground storage tanks.
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 from the tank without detection; as the material spilled it vaporized and spread across the facility. CSB investigators estimate that the vapor cloud spread to a 2000 foot diameter until it reached an ignition source in the northwest section of the facility.
The CSB 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 , employees located in the facility’s control room were unaware of the emergency.
“The filling of a tank without a functioning monitoring system is the type of activity the CSB will be examining very closely,” said Investigator-in-Charge Jeffrey Wanko, P.E. CSP. “The CSB’s investigation will examine operations particular to Caribbean Petroleum, but will also look at the regulations and best practices surrounding the industry as a whole in an effort to improve safety practices at similar facilities.”