Waterloo Fire Rescue responded to a duplex on Tuesday morning after residents reported an unidentifiable odor. Firefighters were dispatched to Randolph Street and West 7th Street around 9:45 AM. After the residents were evacuated, fire crews investigated the odor, but could not officially identify it. It appears, however, that the source may have come from contaminated carpeting. The residents were able to return inside, and no injuries were reported in the incident.