SWAMPSCOTT – A fire official said nobody was hurt and nobody displaced after Swampscott, Lynn and Marblehead firefighters were able to confine a fire to a single room in an Essex Avenue home Saturday afternoon.”We haven’t determined an origin but are looking at a dryer, and the matter is still under investigation,” Swampscott Fire Capt. Graham Archer said Sunday.Firefighters responded at 3:16 p.m. Saturday to 40 Essex Ave., near the Swampscott Train Station, where they found a fire in a room on the second floor of a 2 ?-story wood-frame, two-family home. Lynn Fire Department Engine 5 and Marblehead Fire Department Engine 2 also responded to the scene, Archer said. The fire was classified as a working fire.Archer said that no injuries were reported in the incident and that nobody was believed to have been displaced, as the blaze was contained to a single room.The scene was cleared by 4:34 p.m.