The Lexington Fire Department is investigating the cause of a fire that left one person with serious injuries. It happened just before 6 a.m. at the Tower Plaza Apartments. Firefighters say it started in an apartment on the seventh floor, and caused heavy damage to that apartment. 13 other apartments suffered water damage. Firefighters say one person was taken to the University of Kentucky Medical Center with life-threatening injuries after suffering second and third degree burns. Firefighters say another person was also taken to the hospital for smoke inhalation.