One person has been taken to the hospital after a two-alarm fire in south Sacramento early Thursday morning. The incident happened in a residential neighborhood along the 7500 block of 21st Street. Sacramento Fire says crews responded just after 5:30 a.m. and immediately called for a second-alarm, finding that the incident was more than a single-engine could handle. Heavy smoke and flames could be seen pouring from the structure. Exactly what caught fire is unclear, but at least one home was damaged. Several surrounding structures were threatened. Firefighters had the flames knocked down within an hour. One person was taken to the hospital with burn injuries, firefighters say.