Authorities are investigating after a Florida woman was killed in a port-o-potty explosion Saturday. It happened near a home that's under construction in St. Augustine.    

First responders said the portable toilet was on fire when they  arrived on scene.  After putting out the flames, Firefighters discovered the woman's remains. She has not yet been identified. The State Fire Marshall is investigating and says it's possible the woman was smoking , and ignited fumes from inside the toilet .