A fire tore through a 2½-story home on Hoyt Street in Danbury Saturday morning, displacing residents but causing no injuries. Firefighters arrived within three minutes and quickly knocked down the heavy flames, which started on a second-floor exterior staircase. Seven local and five volunteer fire companies responded, with mutual aid from neighboring towns covering other city calls. Danbury Emergency Management and the American Red Cross are assisting the displaced residents. The cause of the fire is under investigation.