DUNCAN, OK (KSWO) - Arson has been ruled out in a fire this week that destroyed a Duncan business. The State Fire Marshal's office made the announcement today before releasing the scene to the business owner. The Mix Marketplace was ravaged by flames early Tuesday morning. Workers were inside when they smelled smoke, and were able to make it out safely. The fire caused many surrounding businesses to close for several hours. The cause of the fire remains under investigation.