How big is the combustible dust fire and explosion problem around the world? That’s the question that we set out to answer at Dust Safety Science. Determining how to prevent these incidents and related losses of product, life and limb is the driving force behind this work. Since launching combustible dust incident reporting in 2016, we have recorded 961 fires, 357 explosions, 720 injuries and 126 fatalities from dozens of countries around the world. During those six years, the U.S. has averaged 133 fires, 30 explosions and 36 injuries per year with fatalities ranging between one and six per year. Canada has averaged 15.2 fires, 3.5 explosions and 4.2 injuries over that same time period. A breakdown of the incidents captured each year are summarized in Figure 1. The incident data from 2021 is slightly skewed by a particularly devastating methane gas explosion at a coal mine in Gramotenio, Russia, which led to a subsequent coal dust fire in the ventilation shaft. This tragic catastrophe injured at least 157 workers with 51 of those being fatally injured. Once this large outlier incident is removed from the 2021 data, 83% of the remaining injuries in 2021 occurred due to dust explosions, while 17% occurred due to dust fires. All but one of the remaining fatalities in 2021 were due to dust explosions as well. In general, we see that dust explosions cause larger loss of life than dust fires, while dust fires appear to generally cause larger loss of product and damages to the facility. These results indicate that both dust fires and explosions are important to control to reduce personal, financial and facility loss from combustible dust incidents. Materials, Equipment Involved In 2021, 35 of the combustible dust fires and 14 of the explosions reported involved dust from wood or wood products.These incidents resulted in 29% of the injuries (32 total) and 33% of the fatalities (6 total) reported from combustible dust, again once the outlier Russian mine explosion was removed. Figure 2 provides a breakdown between the different materials analyzed in the incident report. The “Other” category includes coal, paper, plastic, textile and other materials less frequently mentioned. In past incident reports, dust collectors were the most often-referenced piece of equipment involved in combustible dust fires and explosions. However, in 2021 only 13% of the incidents occurred in dust collectors. Storage silos such as those used for grain and sawdust storage were the most frequently cited equipment involved in dust figures and explosions in 2021, resulting in eight injuries and one fatality. Wood, Wood Product Industry Examples  In 2021, at least eight combustible dust explosions and two combustible dust fires that caused injuries to workers were reported in the incident reporting system. Some of the fires captured in the incident report include the following. • One worker was fatally injured in a grinder fire at a lumber mill in Michigan. According to the local investigation, the injured employee was located in the cab of the grinder equipment. • One firefighter was hospitalized for heat exhaustion after fighting a pulp and paper mill fire in Florida. • No workers were injured in a pellet mill fire in Maine. The fire started in the wood pellet dryer and extended into the building, damaging the walls, roof and many wire trays. Some of the explosions captured in the incident report include the following. • One worker was injured in a dust explosion reported in a wood pulp dryer and dust collection system in Ohio. The fire was also reported to have spread on light beams and pipes at the facility. • Three workers were killed and five more injured in a lumber mill explosion in Quebec, Canada. The incident occurred while subcontractors were doing repair work on the roof of the plant. • One worker was killed and seven injured in a large wood processing building explosion in Klaipeda, Lithuania. Not much information is available, but a video of the incident posted online shows a rapid explosion propagating throughout the entire building. • One worker received second- and third-degree burns at a sawmill explosion in Weihenzell, Germany. According to local reports, the employee was fixing a blocked conveyor belt when he saw a three-meter-high jet flame moving rapidly toward him. • Seven workers were injured in an explosion at a frame production plant in Beit Shemesh, Israel. According to local responders, the incident included a well-developed fire involving a lot of sawdust. • Three firefighters were injured and one later died of his injuries, while fighting a fire resulting from an explosion at a sawdust processing facility in Segamat, Malaysia. Two of the firefighters fell 10 meters from the third floor, while the third was hit directly by the explosion involving a boiler and sawdust. • Three workers were injured in a wood chip silo explosion in Schameder, Germany. The facility was listed as a German pellet plant although not much information could be found about the incident. • Four workers were injured in a potential dust explosion at a wood pellet company in Georgia. Little information is available on the incident, but the fire chief suggested that some pellets may have overheated and the product ignited resulting in a flash fire and explosion. Closing Thoughts As stated above, both dust fires and dust explosions are common challenges at wood products, woodworking and pelleting facilities around the world. A comprehensive combustible dust safety program must be in place to address these challenges and avoid loss of product, damages to the facility, and harm to employees or other individuals that are on-site at the facility. A comprehensive combustible dust safety program must include several key components, beginning with proper engineering and design of equipment to minimize dust being released into the surrounding environment, as well as ongoing maintenance and inspection programs and adequate dust collection and housekeeping programs. Fire and explosion prevention and protection systems are necessary to avoid loss from these types of incidents when they occur. Training workers to understand the hazards associated with combustible wood dust is another important factor. In particular, on-site workers, external contractors, fire response personnel and others are known to have suffered injuries and fatalities from combustible wood dust explosions—all must be included in the training and education programs used. Finally, the absence of previous incidents at a given facility should not be used as a basis for not implementing a combustible dust safety program. Unfortunately, in many of the cases outlined above, employees may have found themselves stating, “This has never happened here,” right up to the day that the fire or explosion occurred. Author: Chris Cloney Managing director, DustEx Research Ltd. chris@dustsafetyscience.com www.dustsafetyscience.com

Printed in Issue 2, 2022 of Pellet Mill Magazine