Carbon Monoxide FAQ

Frequently Asked Questions

Often referred to as the silent killer, carbon monoxide is talked about more and more. Here, we answer some very common questions about Carbon Monoxide.


Carbon Dioxide (CO2) is NON-TOXIC, Carbon Monoxide (CO) is TOXIC...BIG difference! If your chemistry is rusty, we understand. We hear a lot of customers (and many stores) mix up CO & CO2. The key difference is that CO only has 1 oxygen atom, and CO2 has 2 oxygen atoms. CO really wants to be CO2, so if it can't find a 2nd oxygen to cling to, it will try to cling to something else.

If you breathe in CO, it will cling to the hemoglobin in your blood. Your hemoglobin normally likes to stick to oxygen too, but with CO around, it can't. This is why CO is toxic, it prevents your blood from clinging to oxygen (boy oxygen sure is popular!). CO2 on the other hand, is what we exhale. Both CO and CO2 can be formed by burning things: Whenever anything with carbon in it (e.g. paper or any hydrocarbon fuel) burns, it reacts the the oxygen from the air to form CO & CO2 (as well as other stuff).

Ideally, only CO2 would be formed. In the real world, chemical reactions are never ideal, burning is no exception. If any part of the fuel is burned (reacted) with too little oxygen, it will form Carbon Monoxide (CO) rather than Carbon Dioxide (CO2). This is why the CO Inspector is useful for so many applications, anyplace there is a flame, there is a chance for CO to be present

Carbon monoxide is generated during the process of burning fossil fuels, such as wood, coal, and gasses. In particular, people tend to encounter it in quantity while indoors and burning things without proper ventilation. Think of a running car in a closed garage, or using a portable generator in an enclosed space during a power outage.

During the burning process, carbon is given off. Naturally, it wants to find 2 oxygen atoms to pair with. However, in improperly ventilated environments, it may only find one oxygen atom to connect with, and a carbon monoxide molecule is born.

This is somewhat of a difficult question to answer quickly. It depends on how long you are exposed to it, and how healthy you are. Generally, in disastrous events that would cause someone to pass out and potentially die, large quantities need to be present. However, people with heart conditions may react differently to lower levels than would a perfectly healthy person.

The Consumer Products Safety Council states that immediate impact (disorientation/unconsciousness/death) begins at 150 to 200 PPM, or parts per million.

According to the EPA, you should not be exposed to an average concentration of 9ppm for 8hrs or an average of 35ppm for 1-hr in any given year. It is very common for homes with old furnaces or leaky HVAC systems to have low levels of carbon monoxide in the 5-25ppm range. Continuous exposure to these low levels of carbon monoxide is bad for your health. Most smoke detector style CO detectors won't alarm until at least 70ppm, which is far too high. Source