Explosion at Oregon Wood Treatment Plant

Ran into a series of articles (here, here, and here) about a fire and explosion at a wood treatment plant in The Dales, OR. The fire occurred in a storage tank that had recently been emptied of chemical mixture that is being used as a replacement for creosote in treating railroad ties and telephone poles, coper naphthenate in diesel fuel. From the description of the material left in the tank (“diesel sludge and sawdust remained in the tank”), this may have been a spontaneous combustion event, but the cause of the fire is still under investigation.

All of the news articles include a description of the sound of an explosion associated with the even, but photos in the article show only relatively minor damage to the storage tank involved, so this may have been a case where this was a sealed tank and the combustion products (CO2 and CO) produced an overpressure event that caused a rupture of the tank. This opened that tank to the inflow of air and allowed the fire to flare up, but still remain confined to the tank.

Two fire fighters were injured during their response to the incident and were hospitalized at least overnight according to one report. This would make the fire a Chemical Safety Board reportable incident.