RedactedNarrative: On July 29th at approx. 1600 hours I responded to a report of a boat/marina fire at the McDonalds Hudson Bay Marina. It was reported that a boat had exploded and two subjects were on the boat at the time of the explosion. It was also reported that the two subjects sustained some serious burns. When I arrived on scene, fire personnel were treating the victims and getting them prepared for transport. Fire was also tending to the boat fire that was now out. I contacted some employees of the marina and they stated the owner of the boat had just started the vessel to take his grandson out for a boat ride. As he was pulling out of the covered slip the boat exploded and the boat caught on fire. Employees were able to push the boat away from the marina and rescue the occupants of the boat. None of the employees witnessed the explosion but only heard it. Both occupants of the boat were transported to Kootenai Health and Sacred Heart for further burn treatment 
  
  As I was visually inspecting the boat from approx 200 yards away, I noticed the cabin of the boat was completely burned the hull of the boat was charred but basically intact. I was not able to visually inspect the engine or engine compartment. As I was directing fire personnel to pull the boat closer to shore, the boat began to sink. Eventually all but approx. 3 feet of the bow was completely underwater. I requested a tow service respond to attempt to recover the boat but prior to their arrival, the sank. I went out on the water with the tow service and learned the boat was in approx. 65 feet of water. This location was marked using a buoy and GPS. 
  
  After I cleared the scene I responded to the residence were the mother of the 8 year old victim was supposed to be living. I spoke to the RV manager who told me the mother left the area and was heading to Seattle with her sister as her son and father were transported to Harbor View for further burn treatment. At the time of this report I have not been able to make contact with the boat owner, the son or mother. 
  
  Based on witness accounts and the circumstances around the incident, it appears the boat exploded due to fuel vapors in the bilge and engine compartment that were not properly evacuated. These fumes were the likely cause of the explosion and fire.