On February 7, 2008, an explosion at the sugar refinery in Port Wentworth, Georgia resulted in the deaths of 14 workers. It also injured 36 and caused significant damage to the refinery. Immediately following the incident, we began a very simple root cause analysis, leaving the more detailed analysis for when the Chemical Safety Board (CSB) report was released and more detailed information could be found. The CSB final draft reportwas recently issued and with the information it contains, we can add more detail to our Cause Map.
We can begin our analysis by beginning with a goal that was impacted and using the “5-whys” approach. The 14 deaths and 36 injuries were caused by the propagation of secondary explosions and fire. The secondary explosions and fires were caused by a primary explosion, which was caused by an explosive concentration of sugar dust, which was caused by inadequate housekeeping.
From here we can add more detail to our map. For example, difficulty evacuating the plant was also a cause of the deaths and injuries. The difficulty was caused by having no evacuation drills, and using cell phones and radios to communicate instead of an intercom or emergency alert system.
In order for the explosions to propagate, they needed additional fuel. This was found in the accumulated sugar dust in open areas of the plant, due to inadequate housekeeping, and a dust removal system that was not functioning properly and had ducts filled with sugar dust.
Since “inadequate housekeeping” has now come up twice on our map, let’s expand on that a little. There was a lack of awareness of the hazards of sugar dust. The facility risk assessment did not address these hazards, there was very little training on dust hazards, and there was little regulatory oversight which might have created more awareness or cleanliness requirements. OSHA’s hazardous dust safety standards were limited to grain, and the State of Georgia had no regulations addressing dust. (Both of these issues are in the process of being fixed.)
Although the sugar dust accumulated due to lack of housekeeping, it required more to reach explosive levels. The containment was provided by steel panels installed around the conveyor which were designed to protect the sugar from contamination. The dust also required an ignition source. Due to the extensive damage, the CSB was not able to pinpoint the ignition source.
The CSB identified several solutions that would mitigate the risk of future incidents. Some of these solutions are for Imperial Sugar to implement at this site, such as holding evacuation drills, increasing training on dust hazards, improving the housekeeping program, and installing (and using) an intercom system. As discussed above, OSHA and the State of Georgia are implementing standards and regulations to decrease the chances of a dust explosion in their jurisdictions. Also, the CSB has recommended that the company who performed the risk assessment at Imperial Sugar consider dust hazards as a risk.
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Learn more about dust explosions.