Roseburg Forest Products’ Medford plant experienced a “dust explosion” in one of its silos Wednesday, first responders said, but a company spokesperson said Thursday the silo acted normally and will be repaired while the cause of the incident is investigated.

Between 5:45 and 6 p.m., the plant, located at 2685 N. Pacific Highway, saw “over-pressurization” within a sander dust silo, according to Rebecca Taylor, communications director for Roseburg Forest Products. It was the first over-pressurization incident of this type since Roseburg Forest Products acquired the Medford plant from SierraPine Ltd. in 2015 to manufacture medium-density fiberboard panels.

“The company is investigating the cause of the over-pressurization, so we don’t exactly know what the ignition cause was,” Taylor said. “But we are pleased that the containment equipment worked properly, so that we limited any damage and we were able to resume running promptly.”

None of the plant’s 110 employees were injured, and the facility was operational again by 10 p.m. Wednesday.

While the Medford Fire Department fielded calls from people at the nearby Chick-fil-A saying “flames” were emanating from Roseburg Forestry Products, both Taylor and Jason John, battalion chief for the fire department, confirmed that was not the case.

Medford fire crews arrived at the plant at 5:47 p.m., five minutes after the first dispatch call. Utilizing the plant’s hose lines, hydrants and response team, firefighters hosed down smoldering sawdust from various positions outside the silo, knocking down the fire around 6:15 p.m. Crews left just after 7:30 p.m.

“We’ve dealt with silo incidents with different mills in the valley. We work pretty closely with them. They have really sophisticated systems,” John said. “All of that means that by the time we get there, the incident is pretty well handled.”

Taylor called the episode a “combustion moment” — what can happen when the silo collects fine sander dust particles that are created as a result of the company’s manufacturing processes. 

“Because (sander dust is) airborne, it’s very fine. … This is a risk for combustion,” Taylor said. “The silo we keep it in is designed to suppress and contain a combustion moment like this. It is not something we want to have happen, but it is known to occur.”

Robert Elesky, a truck driver who delivers chemicals for the mill to use, was pulling into the plant to make his delivery when the combustion occurred.

“Imagine having a propane barbecue grill, and leaving the propane on without pushing the ignitor, with the lid closed for a few minutes before pushing it — you can imagine what that would be like; you have a bit of a pop,” Elesky said. 

Taylor said the silo is designed to “pop up” to relieve pressure from the inside.

“That’s what happened yesterday evening,” she said. “The silo functioned properly in relieving this pressure, but then you need to go back and repair it.”

The repair will occur “in the coming days,” said Taylor, who added that Roseburg Forest Products will power the plant with natural gas for now.

Taylor conveyed sympathy to anyone in the community who was worried about the state of the Medford plant. 

“One of our core values as a company is safety and that is the safety of our team members and our community,” Taylor said. “Of course, people are naturally concerned when they hear a bang or learn that the fire department is responding to an incident somewhere. We are very pleased that the equipment we installed in order to contain and suppress this sort of incident works properly.”

Roseburg Forest Products was founded as Roseburg Lumber Company in 1936 by the late Kenneth and Hallie Ford — and the company continues to be family-owned. The wood-products company has since expanded throughout North America, including Arkansas, South Carolina, Virginia and Canada.

The company is in the process of trying to buy 23 acres next to its Medford property to protect its mill.

“They’re afraid of fire risk,” Don Hanson, a hydrogeologist with the Oregon Department of Environmental Quality, told the Rogue Valley Times in June for a story about the possible land purchase. “There are piles of material next to it, so they will be keeping it secure so there are no accidents.”

The property was part of the larger former Medford Corporation (Medco) mill site, which also included the area that is now Northgate Marketplace.

Roseburg Forest Products in December 2022 settled a lawsuit with more than 700 people in Weed, California, for damages from a fast-spreading blaze in September 2022 that killed two people, burned dozens of homes and sent thousands fleeing. The Mill Fire, which started at the company’s veneer plant, quickly burned more than 6 square miles, pushed by 35 mph winds, and destroyed 118 buildings.