RedactedNarrative: On May 21, 2021 at approximately 0900, MNRP along with officers from the U.S. Coast Guard, Sector Maryland - NCR, were on a joint marine patrol when I was dispatched to a boating emergency with a passenger that was suffering from suspected cardiac arrest.  I relayed the information to the crew of the U.S. Coast Guard patrol vessel.  The coxswain of the vessel with the aid of another member began to navigate to the vicinity of navigational aid “Green 15”, north east of Swan Point on the Chesapeake Bay.  
  Several minutes later we arrived at the vessel “Problem Child” to see four passengers at the stern of the vessel.  Coxswain maneuvered the vessel to the starboard side of the vessel.  The Coast Guard and MNRP boarded the vessel to assess the medical emergency.  Immediately upon boarding the vessel we noticed OPERATOR 1, the owner and operator of the vessel suffering from a life threating medical emergency. OPERATOR 1 appeared to be disoriented, confused, and in pain. The other passengers stated that he has had heart conditions in the past. Little did we know at the time, we had just stepped into the beginning of a mass causality event. Coast Guard members and myself started to assess and prepare OPERATOR 1 for transport back to Rock Hall Harbor where emergency services had staged. The other three passengers started to say that they too were not feeling well.  I could see that they could not stand unassisted and were disoriented. Coast Guard members and I started to hand off OPERATOR 1 to another member for transport back to Rock Hall. 
  PASSENGER 1, passed out and started to fall when Coast Guard member grabbed him right before his head hit the deck. PASSENGER 1 is about 6 foot tall and well over 300 pounds.  Now we have two passengers down, one suffering from a reported heart attack and the other from something unknown. I placed two type 4 PFDs under his head and placed him on his side in the recovery position. 
  Coast Guard members and myself turned our attention, once again, at getting OPERATOR 1 off his vessel and getting him placed on the deck of the U. S. Coast Guard patrol vessel. Coast Guard members attended to him until Emergency Medical Technicians arrived on scene. All attention then turned to the remaining passengers. PASSENGER 1 was in and out of consciousness and other passengers were becoming disoriented, confused, and unresponsive to questions.  Something on or in the vessel was adversely affecting these passengers and if not removed immediately the situation would soon turn grave. I made the decision that all parties would have to be removed from “Problem Child” and placed on the Coast Guard vessel and transported to Rock Hall Harbor, where all passengers could be treated medically.  EMT arrived by vessel from Rock Hall and started to assist but the situation was declining fast, and all parties had to be transported posthaste.
  Kent Island's fire boat arrived at "Problem Child" as we were departing to return to Rock Hall. They scanned and anchored the vessel finding extremely high levels of carbon monoxide. They departed the vessel after opening all doors and windows so the vessel could ventilate. 
  While transporting the subjects back to Rock Hall, Coast Guard members asked if I smelled "rotten eggs" and I told him that I didn't smell anything like that. I thought that I could smell exhaust fumes and maybe fuel, which was strange because the vessel was not running when we boarded. 
  Arriving back to the bulkhead in Rock Hall Harbor emergency personnel were standing by.  OPERATOR 1 was airlifted to Shock Trauma in Baltimore, two passengers were ground transported to Chestertown Hospital for further treatment and observation. Another passenger was evaluated, treated on location, and refused any further medical attention.
  
  The passenger asked how he could get back to the vessel.  I told him that it was not advisable to return to the vessel at this time and that it will have to be towed back to Flying Point Marina in Edgewood, Maryland. I told him that he would have to contact Sea Tow or Towboat USA to have the vessel towed to the marina.  I also advised him to inform the company that the vessel has high levels of carbon monoxide and to use caution.  He agreed. 
  After all patients were transported I along with the Coast Guard crew traveled back to the vessel to ensure that it was anchored and get information from the vessel. When we arrived back at "Problem Child" there was a strange smell in the area.  We didn't board the vessel. 
  Several hours later the tow boat captain called the communications center and stated that he could smell something strange and he believed it to be a drug lab on the vessel.  The vessel was towed back to Flying Point Marina where NRP Officers and a hazmat team from Harford County were waiting.  The vessel was searched by the hazmat team and nothing but high levels of carbon monoxide were present. All units cleared. 
  All events occurred in Kent and Harford Counties. No further police action is required at this time.
  