Metal dust fires often have unique properties that make standard fire-fighting techniques unusable and cause it to be harder for firefighters to control them. This means that when firefighters are dealing with most industrial metal dust fires they focus on keeping the flames from spreading and consider the building a total loss.
Unfortunately this happened on July 8, 2015 at the Martin Archery manufacturing building in Walla Walla, Washington. Part of the manufacturing process of these archery bows uses magnesium, with the grinding, sanding, and finishing of the magnesium parts taking place in a specific room. This room has a dust collection system to collect this magnesium dust, and investigators are trying to figure out how the fire began.
Workers closed the room as usual at the end of their shift, but less than a minute later they heard an explosion coming from the room, and saw flames coming from the area when they went back. By the time firefighters arrived the entire building was engulfed, with flames shooting out of the roof.
Magnesium has a chemical reaction when it comes in contact with water, so the firefighters couldn’t start putting out the flames with their water hoses. Magnesium is a highly flammable metal which burns at 5,610° F and releases hydrogen gas when exposed to water.
The Fire Chief on site explained the hazard with putting out a magnesium metal dust fire: “Magnesium is water reactive — when water hits it, it explodes. It was better to let that burn off than try to extinguish it”. The fire crews were able to save the 40,000 square foot office and storage building nearby, and prevented the fire from spreading to residences nearby.
The remains of the Martin Archery factory after the fire was extinguished.
Days later the firefighters continued to put out hot spots as employees viewed the pile of burnt metal that used to be their office. The amount lost due to the fire damage is estimated to be in the millions, which will cause issues for the small town the company is in.
The cause of the fire is unknown, but has been shown to be from the magnesium dust igniting. Magnesium dust has a history of self-igniting when in the right setting, or contact with water could cause a chemical reaction that leads to explosive conditions. If the dust was airborne it could have created an explosive dust cloud, which can be ignited by something as small as static electricity.
Companies that create combustible materials during their manufacturing process need to be extra cautious about removing fire hazards from the workplace. This includes proper housekeeping and cleaning of combustible dusts, an issue OSHA has been paying more attention to. Hughes Environmental technicians are trained in the cleaning and remediation of these explosion and fire risks. Contact us now to find out how we can help you avoid a fire in your facility.
