At 11:45 hours, Katonah fire was dispatched to a reported chimney fire on Leslie Lane. Engine 115 signed on responding moments later and advised incoming units of heavy smoke from the chimney and the basement. E115's crew made entry into the basement. Tanker 6 pulled up and assisted E115 with locating the source of the fire. After a thorough investigation, crews located active fire in the oil burner. Tower Ladder 57 from Bedford Hills was requested to the scene for ventilation and additional manpower. Units operated for approximately 2 hours before clearing the scene.