Skip directly to content

Top 10 Tips on Carbon Monoxide Safety

May 2013 Blog by Mark K. Goldstein, Ph.D. Top CO Safety Tips (1-10)

1. SOURCES: Carbon monoxide (CO) can be generated from fires, fire places, furnaces, generators, power tools, hot water heaters, cooking equipment charcoal grills, vehicles and other 

engines such as lawn mowers, clothes dryers and any combustion.  These risks exist in vehicles, commercial, residential and industrial buildings.

2. MEDICAL TREATMENT: Carbon monoxide (CO) is an invisible gas. CO is tasteless, odorless and is extremely toxic. CO combines with hemoglobin in the blood to form carboxyhemoglobin which is abbreviated COHb.  The percent of COHb in your blood is a marker for the amount of poisoning you have.  The medical community has determined that over 10% COHb requires treatment using either pure oxygen or hyperbaric oxygen, which is just oxygen under pressure.  You are placed in a steel chamber that is pressurized with a high oxygen concentration.

3. HOW CO POISONS: CO bonds with hemoglobin approximately 250 times stronger than oxygen, which is why only a small amount of CO can cause such severe problems and death.  The symptoms vary dramatically from one person to the next.  That is why carbon monoxide is known as the great imitator.   We often hear that flu like symptoms is the most common but other symptoms are possible.  It can simulate or be mistaken for giddiness or even drunkenness. CO poisoning symptoms can influence the cardiovascular system in some people leading to heart attack and/or angina.  Almost every organ in the human body can be affected by lack of oxygen including bladder, kidney, liver, pancreas and many more.  In addition, the sex hormones are attached by CO poisoning.  There are some people that are particularly sensitive to CO.  These include the unborn child, infants, pregnant women and the elderly.  In addition people with cardiovascular impairment (heart problems), cardiorespiratory impairment (lung disease), blood diseases, and people on certain drugs are members of the sensitive population.

4. WHAT LEVEL CAUSES WHAT SYMPTOMS? According to the medical literature some people, for example people with existing angina conditions are sensitive to 15 PPM CO. A 

famous study conducted at three separate locations in the country showed that angina could be brought on by mild exercise. In most healthy adults there are mild symptoms above 30 PPM. For example pilots were tested in Canada with 5% COHb (low levels of CO).  These pilot’s reaction times were seriously affected and this was the primary reason why Canada took the lead in not allowing smoking in commercial aircraft. 100 to 200 PPM CO can produce many symptoms in just a few hours of exposure including confusion, fatigue, lack of ability to concentrate, headache, nausea and heart attacks, seizures and many other symptoms. 200-400 PPM CO can produce severe headache, nausea, dizziness, coma and death in just a few hours of exposure. Any level above 500 PPM is an immediate threat to life.  At levels much higher over 800 PPM CO symptoms may not occur, the victim can lose consciousness before they know anything is wrong.

5. TECHNOLOGY OPTIONS: The three most common CO sensing technologies are: Biotechnology, semiconductor and electrochemical.

5.1 Electrochemical was invented by Robert Sir William Robert Grove. He was born July 1811 and died August 1896. Sir Grove anticipated the theory of the conservation of energy, and was the inventor of the fuel cell and electrochemical sensing technology.  He also invented the first electric light bulb, which was later improved by Thomas Edison. The electrochemical cell has been miniaturized in modern times and is now low cost and effective at measuring CO accurately as long as no Interferent gases are present.  The main problem with simple sensors is they can react with many gases from common household products other than CO such as air fresheners, disinfectants, cleaners, polishes, alcohol, ethylene, ammonia, and almost every hydrocarbon.

5.2 Semiconductor sensors are made from metal oxides.  This sensor was invented in the 1960s by Taguchi in Japan.  Tin oxide is heated by a platinum wire to about 250 degrees Celsius.  The heating cycle is usually about 2.5 minutes and then the power is turned off and readings are taken as the doped tin oxide cools.  The tin oxide is doped with palladium.  CO adds electrons to the surface as it is converted to carbon dioxide by the catalyst system.  The increase of electrons reduces the resistivity signaling the amount of CO by the amount of resistance change.  The technology reacts similarly to various common household chemicals and is not very selective.

5.3 The most modern and most selective of the technologies is called biotechnology.  In the past, it was sometimes referred to a biomimetic as it mimicked the carboxyhemoglobin 

system from 1990 to 1995.  As standards developed in 1996 the sensor was changed to react faster than the human hemoglobin and regenerate much faster so it is no longer truly mimicking the human system but the chemistry is much faster.  The new technology is very selective and was shown by Lawrence Berkeley National Laboratory in 1998 and later by Unified Engineering in 2007 to be the only technology that does not react to common household product such as disinfectants, air fresheners, detergents, cleaners, and alcohols..

6.  INSTALLATION:  NFPA 720-2012 has specific requirements for the location of CO alarms in bedrooms to produce 75 dB at the pillow.  Therefore this requires installation of a CO alarm in every bedroom because if the bedroom door enclosed.

7.  BATTERY: The CO alarm will indicate low battery with a chirp every 30 seconds when the voltage drops below a certain level.  If your alarm requires a new battery replace the battery as soon as possible.  Pulling the battery out and forgetting to replace it can lead to death.

8.  REPLACE ALARM:  Every CO alarm has a limited life.  Replace your alarm every 6 years or sooner if you get a signal.  Older alarms have no replace by date.  If your alarm is older than 2008 replace it now.

9.  SYSTEMS: Carbon Monoxide (CO) system detectors must be listed to UL 2075.  The CO detector should be specifically designed for system 

operation.  UL 2075 requires CO system detectors to have both alarm and trouble relays as well as end of line resistor a form of supervision. Carbon Monoxide (CO) system detectors must be designed to save lives to guarantee that if a problem occurs with the sensor or circuit or if the end of life is reached, the trouble relay will send a message to the central panel.

10. SYSTEMS: Carbon Monoxide (CO) system detectors must now be CO tested at the time of initial installation and annually thereafter. A trained and licensed installer should be contacted to meet and insure these ongoing requirements.