RedactedNarrative: INITIAL CONTACT: I heard Cache County Dispatch informing a Sheriff's Deputy of a medical at the Hyrum Reservoir boat dock. There was supposed to be someone at the dock that had been exposed to carbon monoxide (CO) poisoning. I was in the marina parking lot and responded. I arrived at the dock and initially could not locate the injured party. I then saw a boat coming to the docks with occupants of the boat waving. Cache Valley Ambulance personnel arrived on scene and we met the boat as it pulled up to the dock. A small girl was being carried by her step father. VICTIM initially appeared to be unconscious. She was taken to the ambulance that was waiting on the boat ramp. Medical personnel treated VICTIM with oxygen. Initially her CO level was reported as 40, although medical personnel were having a difficult time getting a consistent reading. VICTIM'S parents decided to transport her to the Cache Valley Specialty Hospital by private vehicle. Medical personnel had VICTIM'S mother sign a medical waiver. 
  
  I later met with mother at the hospital. She said they had checked VICTIM'S CO level again and that it was at 12. She also said that she was being treated in the hyper baric chamber. The treatments would consist of 3 "dives" of 2 hours each over the following 24 hours. 
  
  ACCIDENT: In speaking with the occupants of the boat they said that they had stopped the boat to fill the ballast tanks on the boat; which required the boat engine to remain running. VICTIM and another child had been sitting on and swimming off of the swim deck at the back of the boat for 5 to 10 minutes when syvhect helped them back into the boat. As he went to help VICTIM into the boat he noticed that she was un-responsive. He handed VICTIM to her mother who is a nurse. They assumed that it was possible carbon monoxide poisoning and called 911 and drove to the boat docks. 
  
  ADDITIONAL INFORMATION: On 8/5/2014 I spoke with subject2 by phone. I asked Subject2 if they had recently had any repairs done on the boat. He said that they had not. He did say that typically they operate the boat without the swim deck attached so that they can surf. He said that he had operated the boat a few days after the incident and that he noticed that with the swim deck installed that it seemed to hold the odor of exhaust in the area around the swim deck, but that when the swim deck was removed that he didn't notice the exhaust odor as strong. I asked if the swim deck came from the manufacturer or if it was something that they had installed after purchasing the boat. Subject2 said that the swim deck was original with the boat and came from the manufacturer. 
  
  I asked Subject2 how VICTIM was doing. He said that after the initial treatment in the hospital that she was doing fine.