Carbon monoxide poisoning

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at May 30, 2016
StartDiseasesCarbon monoxide poisoning

Carbon monoxide poisoning involves the inhalation of the carbon monoxide gas and the buildup of carbon monoxide (CO) molecules in the body's system to a sufficient level to be toxic. Because the body's circulatory system readily accepts carbon monoxide faster than other gases such as oxygen during respiration, the toxic level buildup can happen quickly, resulting in loss of consciousness in the victim and possibly death.


Definition & Facts

Carbon monoxide poisoning has been often labeled the silent killer because it can happen without any noticeable warning. CO gas is odorless, colorless, and can easily spread from any kind of burning material. It can't be seen either, so a person could easily walk into a room that is full of the gas without knowing and pass out. Structural fires especially produce large amounts of carbon monoxide which, if not extinguished properly, can build up quickly in a closed or contained environment. 

Symptoms & Complaints

Because CO can't be sensed, the first sign of CO poisoning is often how it begins to affect a victim. Many times the victim will have no idea what's happening, but someone else will notice the change in behavior if the witness is not poisoned to the same degree.

If the person is awake at the time of poisoning, three clear signs will begin to become apparent. First, the person will be suffering from a severe headache due to a lack of oxygen in the bloodstream instead being replaced by CO molecules inhaled.

Second, the person will be extremely red in the face as the body is trying in every way possible to obtain new oxygen. And third, the person will start to become incoherent and listless. Eventually the victim will pass out. Once unconscious, many victims succumb to toxic poisoning and lethal doses; lethal exposure only takes a few minutes.


Poisoning from carbon monoxide poisoning usually comes from two main sources: plumbing gas leaks and burning material. Fireplaces, burning material in an enclosed location, and house fires all can produce lethal amounts of CO if not vented. In offices, fires that reach into the ceiling gaps can spread, burning ceiling tile material and building up CO gas quickly. Natural gas plumbed into homes can also produce CO poisoning, which is why an additive is typically mixed in with municipally-fed gas, smelling like a sulfur smell and acting as a noticeable warning of a gas leak.

The primary issue that generates problem for people with CO is the lack of sufficient air with oxygen to counterbalance the effect of CO to the body. So buildings with trapped air, contained rooms, and structures with failing air ventilation are all locations where CO can easily build up to toxic levels.

A famous and tragic real-life example of this situation was the Station nightclub fire in Rhode Island in 2003 when dozens of people were trapped inside a nightclub where a pyrotechnic fire had occurred. Many died from hot invisible gases and CO poisoning before the fire reached them.

A good number of CO poisonings also occur at home when something goes faulty with the house heating/gas system or if there is a house fire. The victim, already asleep at night may have breathed in too much CO gas, and can't wake up to a fire alarm or the smell of smoke. Victims dying of CO poisoning in house fires happens regularly, even if the fire itself did not actually burn the individual.

Diagnosis & Tests 

The process of confirming a CO poisoning in a victim is accurately confirmed by a blood test. It is not possible to confirm a poisoning by sight or touch alone, but a person's behavior can raise a reasonable suspicion, especially if a fire or a gas leak is discovered in the immediate vicinity or building from which the person escaped.

Treatment & Therapy

Initial immediate treatment for CO poisoning is to get the victim outside with fresh air or oxygen therapy as fast as possible. If already awake, the person needs to be kept from going unconscious long enough for the body to begin replenishing itself with fresh oxygen.

Medical treatment onsite will often involve masked oxygen treatment for the victim by an EMT or paramedic responding to the scene. In especially severe cases, a victim could be put into an air pressure chamber at a hospital to force oxygen into the body as fast possible. 

Prevention & Prophylaxis

Ideally, the best way to prevent CO poisoning is to make sure it doesn't happen in the first place. That means to always follow proper venting protocols with home fireplaces, cook with ventilation, turn off all burning units or flues when not in use, and avoid burning in an enclosed room.

Additionally, a home should be checked regularly for gas leaks, even small ones. All homes should have a CO monitor or alarm set and ready on every floor since the gas cannot be detected otherwise. And a home heater should be checked annually as cracked flues in the heater can also be a source of CO poisoning through a home heater vent system.

When the home alarm goes off or there is a house fire, the best approach is to get everyone awake and outside as quickly as possible. Trying to stay inside to stop the fire can easily get oneself trapped and overwhelmed by the fast buildup of CO gas in a burning room. Once unconscious, the person will need rescuing as well as people who don't re-awake on their own from CO poisoning inside a room full of CO gas.

If a person has to work or function in an environment that has significant ongoing burning, combustion or exposure to natural gas, then the environment should be properly vented or the person should be provided a sufficient breathing apparatus.

Portable air blowers and fans are the most viable equipment for such situations. Firefighters, for example, do not enter burning homes or buildings now without a self-contained breathing apparatus, better known as a mask and oxygen tank.