CAUTION: Any vessel with either LPG or CNG appliances and/or an internal combustion engine, is subject to a risk of Carbon Monoxide (CO) poisoning and/or oxygen depletion. It is critical that you maintain these appliances in perfect order. Read the owners manual carefully. Establish a preventive maintenance schedule.

• Gas refrigerators: These units are subject to rust and scale falling onto the burner unit thus causing incomplete combustion and high output of CO. Units should be installed in such a way that the burner box can be readily inspected. In ideal installations, the burner portion of the unit is completely isolated and sealed from any living quarters or any possible channel to explosive fumes.
• Instant LPG hot water heaters: Any installation in which an instant-on LPG hot water heater unit is installed in the same compartment as the user is suspect and potentially lethal. Oxygen depletion and carbon monoxide poisoning is a serious hazard to those using units in small head compartments with windows and ventilators shut. The possibility of igniting hair spray or other fumes also exists. Remove these units to compartments completely away from living quarters and the potential of explosive fumes. Do not install in any locker that may have gasoline or other explosive liquid fumes nor a locker into which LPG could possibly leak. Triple-check to make sure you have proper ventilation and a ignition resistant flue or exhaust vent.

NOTE: BOTH THE ABOVE UNITS are not ABYC compliant. Many hundreds are in routine use worldwide and are found mostly on older vessels and foreign built vessels.

• Ranges, ovens, grills: Units that are not thermocouple protected must be monitored very carefully. If the flame blows out in an unprotected unit gas will continue flowing. Propane, being heavier than air, will sink to the bottom. Compressed natural gas, being lighter than air, will rise to the top. In a certain cases that can be more dangerous than falling to the bottom.

All appliances must have combustion protection surrounding their installed area and especially directly above the open burners.

All the above may produce Carbon Monoxide (CO) when burning fuel. If the appliance is not operating properly, it can create exceptional amounts of CO. ALL fuel-burning appliances must be treated with utmost caution. Maintenance is the watchword.

A serious carbon monoxide problems come from running generators all night for AC or having swimmers in the water directly behind the vessel with engines or generator running. There have been many deaths from this of late. Modern boats have many fuel burning systems running and CO should be carefully monitored and everyone on board should be made aware of the potential problem. Sleeping with generators running is bad policy, no matter how good the installation.