All but one of the occupants of a hotel in Walnut Creek returned to their rooms Saturday night after a possible hazardous materials incident, officials with the Contra Costa County Fire Protection District said. One person was taken to a hospital after someone called fire officials at 8:57 p.m. to report six people were having difficulty breathing and their eyes and throats were burning at the Holiday Inn Express at 2730 N. Main St., near Interstate Highway 680. The other five were treated outside the hotel, Contra Costa County Fire Protection District Fire Marshal Robert Marshall said. More than 100 people were evacuated from the hotel. The six who suffered symptoms told firefighters of a pepper-like odor in one of the hallways. Crews were not able to locate any hazardous substance and as of 10:37 p.m. all but one of the occupants had returned to their rooms.