A firefighter was seriously injured Wednesday morning after he fell out of a building during a training exercise. According to Largo Fire Rescue, the firefighter was rappelling out of a second-story window at the department's training grounds at 751 16th Ave. SE when his equipment failed about 9:30 a.m. He fell one story, or 14 feet, and landed on his back. The firefighter, whose name has not been released, was taken to Bayfront Health St. Petersburg, officials said. He sustained a spine fracture and will need three to six months to recover. He was otherwise in stable condition, the city said.