Is Carbon Dioxide Flammable? (CO2) 

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Carbon dioxide (CO2) is produced by nearly every animal on the planet and is consumed by nearly every plant. It’s a gas at room temperature and occurs naturally in the environment in trace amounts. It accounts for about 0.04% of the gases in our atmosphere and this is up from about 0.03% before the industrial revolution. But is it flammable and are we at risk of burning because of this rising level of CO2

Carbon dioxide is the end product of carbon burning in oxygen. In this reaction, the carbon has been completely consumed. This means that carbon dioxide is not flammable as it will not react anymore with oxygen, no matter how hot things become.

This doesn’t mean that we can ignore carbon dioxide in relation to fire though. Here is what you need to know.

Your # 1 priority is keeping your family safe. As a firefighter, I recommend everyone has updated smoke detectors that don’t require battery changes, like these ones from Kidde, a fire extinguisher, like this one from Amerex, and a fire escape ladder if you have bedrooms above the first floor, I recommend this one from Hausse.

Also read: What Makes Something Flammable?

What Is CO2?

Carbon Dioxide CO2

Carbon dioxide or CO2 is a gas where each atom of carbon is bonded to two atoms of oxygen. 

The oxygen atoms form a double bond with the carbon atoms and it’s a very stable arrangement that leads to carbon dioxide being, mainly, unreactive. 

Carbon dioxide dissolves in water, however, relatively easily and much of the natural carbon dioxide is stored in lakes, rivers, seas, glaciers, polar ice, etc. 

It is used in carbonated drinks in high quantities, and this is why sparkling water has a slightly sharp, acidic taste to it, it’s the flavor of carbon dioxide.

While you may have heard bad things about carbon dioxide, in relation to the environment, it is important to realize that it is essential for life on earth too.

Carbon dioxide is the main source of carbon for all life forms on the planet and plants and algae depend on it to affix carbon in their bodies directly. 

Plants thus, breathe in carbon dioxide and exhale oxygen which is good for human beings because we exhale carbon dioxide and breathe in oxygen. 

Carbon dioxide is also produced when dead organisms decay and during the fermentation process for producing alcohols or bread. 

It can also be made by burning any organic substance including wood and peat and by burning fossil fuels such as oil, coal, gas, etc. 

Also read: Is Ozone Flammable? No, But It is a Fire Hazard…

Is Carbon Dioxide Highly Flammable?

Carbon dioxide is not at all flammable because the carbon is fully bonded with oxygen. 

This means that carbon dioxide will not catch light in the presence of oxygen at any temperature. 

Is CO2 Gas Combustible?

For exactly the same reasons, carbon dioxide is not considered to be combustible either and it will not burn even when frozen into a solid. 

Can Carbon Dioxide Cause An Explosion?

This doesn’t mean, however, that you can’t use carbon dioxide to cause an explosion. 

Like all gasses, if you want to store carbon dioxide, you need to put it in containers (usually metal cylinders) and like most gasses, due to its poor reactivity, you can pressurize carbon dioxide to fit quite a lot of gas into a very small space.

The problem with this is that if you heat the container, the gas expands, this increases the pressure within the container, if the pressure gets high enough the gas will rip the container apart spewing shrapnel everywhere.

You can see this on a small skill with CO2 cartridges here:

This is an explosion, even if it involves no burning of carbon dioxide. 

Is Carbon Dioxide Poisonous To Humans?

Carbon dioxide is not poisonous to humans in ordinary quantities. 

It would be highly problematic if it was because every single one of our cells produces carbon dioxide as it burns sugar and fats for fuel. 

How Is It Removed From The Body?

Instead, the carbon dioxide produced is transported by the red blood cells to the lungs and is then exhaled. 

What Happens If You Breathe In CO2?

You are breathing in carbon dioxide as you read this article as about 0.04% of the air we breathe is carbon dioxide and as you can see, it’s not doing you any harm. 

However, it’s important to realize that if we were to breathe in large quantities of carbon dioxide without enough oxygen, we would have real problems. 

Though carbon dioxide is not poisonous, without oxygen and in an atmosphere full of CO2, we would suffocate. 

Early warning signs of carbon dioxide suffocation (asphyxia) include rapid breathing, rapid heart rate, emotional distress, fatigue, physical coordination problems which can progress to nausea, collapse, vomiting, coma, and eventually death.

The good news is that you can treat this by simply moving to somewhere with more oxygen (which we admit is often easier said than done, particularly if you are breathing carbon dioxide as the result of a fire) and the problem soon reverses itself.

The bad news is that if any damage is done to your heart and brain during this process, it is likely to be permanent. 

How Much CO2 Do We Breathe Out?

If you’re curious about how much CO2 that you produce, it’s been found that the average person breathes out about 2.3 lbs. of CO2 each day.

This average hides the true picture though as a highly active adult will breathe out about 8 times as much CO2 as someone who barely gets out of their office chair all day!

What Happens If It Is Not Removed From The Body?

If you don’t breathe out the carbon dioxide that your body produces, then the end result is carbon dioxide asphyxiation and potentially other problems from CO2 build up in your organs.

CO2 is a mild acid and while it’s not problematic in small quantities as it becomes more concentrated it can damage the organs and tissues around them. 

It is impossible to hold your breath and attempt to overdose on CO2, though, in the same way, that no one can strangle themselves. 

You quickly run out of oxygen and pass out, and then commence breathing normally again when your body relaxes. 

The only time carbon dioxide is going to get trapped in your body is if you are suffering from respiratory failure. 

Can A CO2 Leak Kill You?

A carbon dioxide leak could be deadly if it occurred in a small and poorly ventilated space. 

For example, if you work in a workshop and a cylinder of CO2 were to fracture, it could drive the oxygen out of the space and asphyxiate you. 

However, it would be a rarity and we couldn’t find an example of this happening. 

It’s worth noting that CO2 still kills plenty of people each year as a byproduct of fire in burning buildings where it asphyxiates those trapped in these spaces. 

Why Is Releasing Carbon Dioxide Bad?

Carbon dioxide is a recognized “greenhouse gas”.

That is when it is present in excess in the atmosphere, CO2 traps the sun’s energy inside the atmosphere and prevents it from being radiated into space. 

This, in turn, causes the planet to warm and the oceans to warm.

We call this “climate change” or “global warming” and it is known to affect the weather patterns of the planet as well as have extremely negative consequences for many lifeforms. 

Why Is It The Worst Greenhouse Gas?

Carbon dioxide is the worst greenhouse gas because it’s the most prevalent. 

About three-quarters of all the greenhouse gas present in our atmosphere is CO2

And unfortunately, because it’s not very reactive, CO2 stays in the atmosphere for thousands of years. 

Can You Smell Carbon Dioxide?

Carbon dioxide is an odorless and invisible gas. 

If you breathe out in a cold environment, the vapor you can see is water vapor condensing, not CO2

How Can I Reduce It In My Home?

If you’d like to keep CO2 to a minimum in your home, you can take some basic steps to reduce it.

Firstly, ensure that everyone smokes outside (or better still, stops smoking at all), and then that you have any fireplaces outdoors rather than indoors, that you don’t use candles, and that when you use your range, the extract fan is running and that you have your window open to improve airflow. 

You can also buy a CO2 monitor which tracks CO2 levels in your home and see the impact your actions are having. 


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