RedactedNarrative: On April 12 2015, at approximately 2:30 p.m., operator was launching his vessel (LA-5441-GA) at the Moon Lake boat launch on the Ouachita River. Operator1 prepared his vessel to launch away from the boat ramp, checking batteries, ballast pumps, and ran the blower. Operator1 then backed the vessel down the ramp and placed the vessel in the water. He then boarded the vessel and started to crank the engine when he heard an explosion from the engine compartment and turned to see flames coming from the rear of the vessel. The primary factor causing the explosion came from a build up of fuel vapors in the engine compartment. Operator1 got out of the vessel and pushed it off the trailer to get distance from himself and his truck. Operator1 called 911, approximately 20 minutes later the fire department arrived and put out the fire. Once the fire was extinguished the vessel was pulled back to the trailer and water was pumped out of the vessel so that it could be loaded back on the trailer. 
   
  The primary factor for the explosion was a build up of fuel vapor inside the engine compartment. The secondary factor was faulty equipment allowing fuel vapors to escape from the fuel lines or holding tank. The tertiary factor causing the explosion was due to the blowers not being run for an adequate amount of time to remove all vapors from the engine compartment.
   
  Senior Deputy with the Office of State Fire Marshall was contacted. Throughout Sr Deputy investigation, he was able to determine that escaping gas fumes caused a fuel air explosion. Sr. Deputy investigation determined that all causes were accidental and his supplemental report is attached to this report.
   