Abstract: A fire of unknown origin started in a rubber compound mixing machine located on the second floor of a three-story compound-production building attached to the tire production area at this worksite. The fire started with a loud explosion and was pulled into the duct work of the dust control system by the ventilation fan of the dust control system. The fan pulled the fire in to the bag-house system which caught fire. The filter bags and their support system were destroyed by the fire. There were ten employees exposed to the smoke from the fire. Most of the employees exposed to the smoke were working on the second floor adjacent to the rubber mixing machine or were cleaning up in the work area on the second floor. These employees were taken to a local hospital emergency room for evaluation. No employees were hospitalized for medical treatment.