RedactedNarrative: On 09/02/2017 at approximately 1504 hours I Game Warden, for the Kansas Department of Wildlife, Parks and Tourism was called out for an injury boat accident that occurred on Wilson Lake in Russell County, Kansas. I Responded. When I arrived I spoke with Park Ranger and he told me that the two injured people had been transported by ambulance to Salina regional Hospital. 
  
  I spoke with an owner of the vessel. She was in the process of removing the vessel from the water. I called GW and he went to Salina Regional Hospital and Interviewed two people. They received 1st and second degree burns on the sides of their bodies. I then spoke with GW and he responded to assist me with inspecting the vessel.
  
   While waiting for GW I interviewed the owner and operator of the vessel. Operator told me that he unloaded the vessel at Lucas Point boat ramp and immediately drove to the marina to get fuel. He then told me that he had to wait in line at the marina so he parked in a slip. When it was his time he started his vessel and pulled next to the fuel dock with the starboard side of the vessel tied to the fuel dock. 
  
  Operator then told me that after fueling was complete he loaded the passengers which were Occupant1 who was seated on the port side in front of the console, Operator who was seated in the seat located in the bow of the vessel, Occupant2 who was seated on the Starboard side of the vessel in front of the drivers'' console, Occupant3 who was in the captains'' chair on the starboard side. Occupant4 who was seat on the starboard side behind the drivers'' seat, Occupant5 who was seated on the starboard side in the farthest seat near the back of the vessel back onto the vessel, Occupant6 was seated on the port side of the vessel in the furthest rear seat and Occupant7 who was seated on the Port side of the vessel behind the console. Occupant3 turned his ventilation on for approximately 3-5 seconds and then started the vessel and heard a loud pop which he said could have been the vessel back firing. At this time the vessel (Fuel Vapors) Ignited in the rear of the vessel. All occupants of the vessel except for Occupant3 voluntarily exited the vessel. Operator got the fire extinguisher from the Marina fuel dock and used it. The vessel was also untied from the dock at this time and pushed away from the dock. After getting the fire out Operator sad he pulled the exhaust off (Backfire flame arrestor).
   
  At approximately 2140 GW arrived and we visually inspected the vessel. We found that the backfire flame arrestor was off of the vessel. It did however appear to have been on the vessel at the time of the fire, due to the amount of fire extinguisher dust on the cap. There was also an absence of fire extinguisher dust inside where the backfire flame arrestor covered. No other serious damage was done to the vessel. GW and I also took pictures and the cleared the scene.