On October 1, 2003, a 44-year-old male volunteer fire fighter and a 42-year-old male volunteer fire fighter were fatally injured by a silo explosion at a lumber company. The victims responded to a mutual aid call from a neighboring volunteer fire department already on the scene at the silo fire. Prior to the explosion, fire fighters had opened some exterior hatches at the base of an oxygen-limiting silo and were flowing water through the hatch openings with a piercing nozzle. Fire fighters were also flowing water into the top of the silo via an aerial apparatus. At the time of the explosion, one victim was standing on top of the silo and the other victim was in the aerial basket positioned beside the top of the silo. Eight other fire fighters were injured during the explosion, two requiring hospitalization. The fatally injured victims were transported to regional hospitals via ambulance where they were later pronounced dead. NIOSH investigators concluded that, to minimize the risk of similar occurrences, fire departments should: 1. Train officers and fire fighters on the hazards associated with different types of silos and the appropriate fire fighting tactics; 2. Develop and implement standard operating guidelines (SOGs) for fighting oxygen-limiting silo fires; and, 3. Ensure that pre-emergency planning is completed for silos within their jurisdictions. Additionally: 1. Facilities with oxygen-limiting silos should ensure the proper operation and maintenance of their silos; 2. Municipalities should consider requiring an exterior placard with specific silo information for use during fire fighting efforts; and, 3. Silo manufacturers and research organizations should consider researching the causes and mechanisms of silo fires involving wood products and developing engineering approaches to reduce the risks to fire fighters.