RedactedNarrative: Vessel 1 was cruising on the Banana River for approximately 2 hours when the occupants became ill with nausea, headache, and dizziness.
  
  On 07/12/2016 at approximately 1000 hours, Vessel 1 departed from the dock on the Banana River at State Road 520.  Vessel 1 was cruising on the Banana River at slow speed.  Approximately 2 to 3 hours into the voyage, Occupants became ill with symptoms of nausea, headache, and dizziness.  At the onset of the symptoms, two people were moving back and forth from the cabin area to the deck.  Another was on the deck at the stern of the vessel.  Two more were in the berthing area inside the cabin.  When the occupants’ symptoms became worse the vessel Operator called 911, shut down the engines, and anchored the vessel in the Barge Canal.  All 6 occupants were transported from the vessel to the Sea Ray Sykes Creek Plant.  5 of the occupants were treated by Brevard County Fire/Rescue for symptoms possibly related to carbon monoxide poisoning.  4 of the occupants were transported to Cape Canaveral Hospital via ambulance.  They were treated and later released from the hospital.
  
  Vessel 1 was inspected for possible ventilation system failure.  The ventilation system was already turned on prior to the inspection and appeared to be working properly.  No electrical or mechanical system failures were found during the inspection.  An auxiliary carbon monoxide detector located in the cabin of the vessel was inspected and found not working.  Unable to determine what caused the occupants to become ill/sick.;