Lake Mead rangers and firefighters and Clark County FD firefighters responded to a boat explosion in the Callville Bay Marina yesterday evening. Seven people from Las Vegas were aboard when the explosion happened. Five were injured; three were transported by ambulance to University Medical Center, but the other two declined treatment. Injuries included burns and abrasions. Forever Resorts marina employees provided first aid to the injured and protected visitors by moving the boat away from the marina. While the exact cause of the incident remains under investigation, investigators suspect that this may have been caused by a buildup of gasoline fumes.