Carbon Monoxide Poisoning
Carbon monoxide (CO) is an odorless, colorless gas that can cause sudden illness and death if someone breathes too much of it. CO can build up in enclosed or semi-enclosed spaces and poison the people and animals in them.

CO is produced any time a fossil fuel is burned in a furnace, vehicle, generator, grill, or elsewhere.

• Don't use a generator, charcoal grill, camp stove, or other gasoline or charcoal-burning device inside your home, basement, or garage or near a window.
  
• Don't run a car or truck inside a garage attached to your house, even if you leave the door open.
  
• Don't burn anything in a stove or fireplace that isn't vented.
  
• Don't heat your house with a gas oven.
  
• Don't mix household products together. Mixing bleach and ammonia can result in toxic gases.

Symptoms of Carbon monoxide (CO) Poisoning
The most common symptoms of CO poisoning are headache, dizziness, weakness, nausea, vomiting, chest pain, and confusion. High levels of CO inhalation can cause death. CO poisoning can also cause you to pass out and fall into the water and drown. A person who is sleeping or intoxicated can die from CO poisoning before ever having symptoms. Seek prompt medical attention if you suspect CO poisoning and are feeling dizzy, light-headed, or nauseous.

Have your heating system, water heater and any other gas, oil, or coal burning appliances serviced by a qualified technician every year.
Install a battery-operated CO detector in your home and check or replace the battery when you change the time on your clocks each spring and fall. If the detector sounds leave your home immediately and call 911.

Source: cdc.gov

Carbon Monoxide Poisoning on Boats
Gasoline-powered engines on boats, including onboard generators, produce carbon monoxide (CO).

• Larger boats, such as houseboats, sometimes have generators that vent toward the rear of the boat. This venting poses a danger of CO poisoning to people on the rear swim deck or water platform. On larger boats CO builds up above the water near the water platform. CO that builds up in the air space beneath the stern deck or on and near the swim deck can kill someone in seconds.
• Traveling at slow speeds or idling in the water can cause CO to build up in a boat's cabin, cockpit, bridge, and aft deck, or in an open area. Wind from the aft section of the boat can increase this buildup of CO.
• Back drafting can cause CO to build up inside the cabin, cockpit, and bridge when a boat is operated at a high bow angle, is improperly or heavily loaded, or has an opening that draws in exhaust.
• Never block exhaust outlets. Blocking outlets can cause CO to build up in the cabin and cockpit areas–even when hatches, windows, portholes, and doors are closed.
• Dock, beach, or anchor at least 20 feet away from the nearest boat that is running a generator or engine. Exhaust from a nearby vessel can send CO into the cabin and cockpit of a boat.
• Install and maintain a working CO detector inside the boat to alert people when dangerous levels of CO have built up inside the boat cabin.

If you think a person on your boat has CO poisoning move him or her to fresh air right away and contact the nearest emergency services.

Source: cdc.gov