DSS192: Incident Update - 2021 Flour Dust Explosion in Savannah, Georgia

In today’s episode of the Dust Safety Science podcast, we present an incident update on the 2021 flour dust explosion in Savannah, Georgia.

We have our Road to Zero Mission to see one year of zero fatalities worldwide by 2038. Our incident database is our measuring stick, and that’s where we really evaluate what’s happened every year. For example:

What kind of challenges are coming up at a systematic level in terms of combustible dust safety?
Is one region of the world doing things in a different way and seeing successes that other regions of the world are not? And vice versa.

Consequently, we’ve been really trying to double down this year on how we can make the incidents that we’re capturing in this database more valuable. One of those methods is doing what we’re calling enhanced research. We’re reaching out to gather Fire Marshal reports and detective investigations and do legal follow-up with victims and survivors to better understand the life cycle of these combustible dust incidents and develop solutions moving forward.

Overview of Flour Dust Explosion

On September 14th, 2021, an explosion occurred at a baked goods factory in Savannah, Georgia. The site was about 20 minutes away from the Imperial Sugar Refinery, which witnessed one of the most infamous explosions in North America for at least the last two decades.

In the local reporting, firefighters reported a ‘small dust explosion’ which occurred in the flour mixing room of the bakery. After the explosion, one wall was damaged and two employees suffered minor injuries.

That was all the information that was available. Some general questions that were left unanswered were: what type of equipment was involved in the incident, what was the ignition source and how the incident happened. And most importantly, how could this be prevented moving forward? What are some of the key takeaways?

When we obtained a copy of Savannah Fire Department incident number 21-8292, it indicated that the facility was a single-storey food processing plant, and that when firefighters arrived on the scene, all flames had been extinguished by the plant suppression system. They noted that the explosion occurred in the sifting room, and that the sifting room was a concrete block enclosure with a plastic curtain over the single exit. This was reportedly to contain dust inside of the sifting room from getting out or migrating to other parts of the facility.

The wall directly across from this curtain was charred and a roll-up metal door was damaged by pressure waves, and a metal panel above another door was displaced in an outward direction, indicating pressure loads from a deflagration in the sifting room.

In the sifting room, the investigators found a large amount of flour and water. Some of the electrical controls in the room were encased in what appeared to be an explosion-proof box. Furthermore, the investigator photographed several electrical components within the room, which appeared damaged or exposed and could have caused the ignition. He doesn’t specify if the damage he refers to was caused by the explosion or if it existed beforehand.

A video showed that no one was in the vicinity of the production room before the explosion. According to the initial local news report, two workers were reported injured, but it does not specify how they were injured.

The report does state that there have been $25,000 in damages. Furthermore, the investigator states that maintenance personnel contacted him after finding a wire that appeared to have been mechanically damaged by a falling bag and showed electrical arcing. He says that he was not able to get back on the scene to confirm the report of this damaged cord.

Takeaways From the Report

There are some interesting things we learned from getting this extra information.

It does sound like the facility had protection measures in place to prevent at least some ignition sources inside the sifting room, and also to prevent migration of flour dust from outside the sifting room into the hallway and to other parts of the facility.
Multiple ignition sources may have been present in the sifting room at the time of the incident due to damaged or exposed mechanical or electrical systems. Fortunately, there were no workers in the area at the time of the explosion, and the explosion was limited to the sifting room.
Before the fire department team arrived, the suppression system extinguished the fire.

There were three main takeaways then from this enhanced incident research:

The first one was keeping employees away from high-risk areas. In the case of this incident, employees were not in the area where dust and ignition sources were located. It’s unclear if that was standard practice or not, but at least they were not in the vicinity.
The second is the importance of inspection and ongoing maintenance checks. They did have electrical controls in the room that were encased in what appeared to be explosion-proof housing. But they also had other electrical components that looked like they were damaged or may have exposure and be able to arc.
The third is avoidance of dust migration, which can really reduce the chance of having knock-on incidents or incident escalation. In this case, if they didn’t have those curtains up or some way to segregate that room off, it could have been much worse.

Conclusion

Dust fires and explosions are complex events that are rarely explored in detail in traditional news outlets. Enhanced research is often necessary to dig beneath the surface, find out how an incident may have occurred, and use that information to advocate change for the better.