MEMPHIS, Tenn. (AP) – Fire officials say a natural gas leak from a water heater caused an explosion that injured seven people in a home in Memphis, Tennessee. Memphis Fire Department Lt. Wayne Cooke said four adults and three children were taken to hospitals with second- and third-degree burns on 70% to 80% of their bodies after the explosion Thursday night. The adults injured in the explosion are in their 30s. Cooke said the children are 4, 10 and 13 years old. When firefighters arrived, they found that the exterior of the one-story, wood-frame house had collapsed. They searched the house but found that everyone had already exited. .