Breath of Peril: Weaving CO2 Hazards Into Your Fiction

 Silent, odorless, and deadly—carbon dioxide poisoning is an often-overlooked but chilling threat in fiction. Whether you're crafting suspenseful mysteries, survival thrillers, hard-hitting sci-fi, or anything else, understanding how CO₂ exposure works can add tension and authenticity to your storytelling.

In this episode, we break down the science of carbon dioxide poisoning, uncover little-known causes of carbon dioxide buildup, and explore gripping ways to incorporate this invisible danger into your stories. Learn how real-world survival scenarios can inspire unforgettable plot twists and heighten stakes for your characters.

✅ How CO₂ poisoning actually happens ✅ Ways to weave atmospheric threats into your setting and plot ✅ Examples of powerful suspense scenes featuring invisible dangers

Perfect for fiction writers seeking to enhance realism, craft high-stakes conflict, and keep readers on the edge of their seats.

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#FictionWriting #SuspensefulStories #CO2Poisoning #InvisibleThreats #ThrillerWriting #SurvivalStorytelling

Transcript

Imagine a story where invisible danger lurks in the air itself—carbon dioxide poisoning, a silent antagonist for your fiction stories. This episode dives into the chilling realities of CO₂ exposure, unraveling its natural origins like volcanic eruptions and cave ‘death pockets,’ alongside man-made sources such as industrial mishaps and poorly ventilated spaces. Discover how characters might unwittingly stumble into peril, the subtle signs and symptoms that build tension, and the catastrophic ways survival plans can go awry. Whether you’re storycrafting thrillers, survival tales, or historical dramas, this exploration promises to add depth, danger, and realism to your storytelling toolkit. Buckle up for a journey into the science and suspense of CO₂ poisoning!

Welcome to Writing Rural with Alley, the fiction writer’s weekly inspiration station for rural life and lifestyles, from historical to post-apocalyptic, helping you bring your rural stories to life! I’m Alley, and this is episode #106, Breath of Peril: Weaving CO2 Hazards Into Your Fiction. Stick around to the end to find out all the ways things could possibly go wrong in your story. 

Before we start, I know I was supposed to be back last week, but my recovery from a routine procedure took longer than expected. However, I’m back and feeling fine. I even have a special announcement at the end of this episode that you don’t want to miss. 

Now, let’s get into this.

Carbon dioxide (CO2) is a colorless, odorless gas that is harmless in low amounts but becomes dangerous, or even deadly, in high amounts. Now, let me be clear: carbon dioxide and carbon monoxide are two different types of gas. While both are potentially deadly, they have many differences. One of which is that carbon dioxide is not flammable. And since I tend to mix up the two names, I will refer to carbon dioxide as CO2 for the episode. 

Let’s cover some basic science so everyone is on the same page, and I promise it will be important later in the episode. We all likely remember the lessons about humans breathing in oxygen and breathing out CO2. Plants then use the CO2 in photosynthesis and make oxygen. If your school was anything like mine, this was linked to why we need the rainforests so much. 

Another characteristic of CO2 is that it is heavier than air. Now I have looked through several sciences sites, and they can’t agree how much heavier it is. I have found 53% to 55% heavier. I did ask AI, and it said, 37.5%. Take that how you will, but the point is, it’s sinks, so to speak. This means it pools in low-lying areas. These pools are known as death pockets. 

Now there are many natural sources of CO2 and man-made sources. Let’s start with the natural sources. 

First is volcanos, or volcanic activity. Volcanos can emit high amounts of CO2 into the atmosphere. This sounds mild until you remember that CO2 is heavier than air. That means that the CO2 can pool in valleys or other low-lying areas. There are theories that some of the people in Pompeii that were underground in food storage areas may have died of CO2 poisoning, since the CO2 would settle in low areas. Not only can CO2 kill people, but it can also kill animals. This could be devastating to eco systems. 

Earthquakes can also release CO2 along the fault line. This holds the same dangers as with volcanos, on top of the devastation a large earthquake would cause. Keep in mind, volcano eruptions can cause, or be caused by, an earthquake. 

There is also something called lake overturn. This is where volcanic activity, earthquakes or other natural phenomenons cause large amounts of CO2 to be released below the water and rise to the surface. Any poor unsuspecting sailor who sailed through this could end up in a deadly situation. Not only are sailors at risk of dying, but so are any fish who swim through the area. 

Both volcanoes and earthquakes can also release CO2 into caves or mineshafts. Caves rarely have good ventilation, and if there was even a minor earthquake, this could cause a cave in or even damage the ventilation shafts of a mine. 

Even without such violent natural catastrophes, there are other natural phenomenons that can lead to CO2 pockets inside of a cave or a mineshaft. Historically, people would take a torch, candle, lantern or other flame, and if the flame went out, they knew the air was no longer safe. There is one very important thing to know about using flames. There can be different types of gases that are deadly in caves, including methane. Methane gas is flammable. I’m sure you can see where this is going. 

The flame test was also something done when digging wells in case they dug into an underground pocket of CO2. Wells were most often dug with more than one person, and the person inside was tied to a rope. If the light went out, they could be dragged out this way. Sadly, this is a lesson that was usually learned the hard way. 

Another natural source that is little thought about is hot springs and geysers. Ok, I know, not all of them release CO2 and there are many popular tourist destinations to these. However, there are still many that do. This can be a danger to both people and any animals who go there for a drink. 

The next natural one is respiration. Ok, I know, that sounds weird, but stick with me. Remember how humans and animals breathe in oxygen and breathe our CO2? Well then they are in tightly sealed areas, there is a risk of CO2 poisoning from respiration if there is no air ventilation. I suppose, in theory, a barn could do this, but I will be honest. I have never seen a barn that was sealed well enough. They all seem to be drafty. 

This is mostly shown in movies in one of two ways. In a car that is buried under snow, or something similar, or being buried alive. Being buried alive was a true risk, and reality in history. It’s why grave bells were made in case anyone was buried alive. Too many times, they would dig up a body only to find claw marks on the inside of the coffin, and the person would have died of CO2 poisoning instead. I have heard stories of this with people being bricked into walls as a death sentence for their crimes. 

Speaking of being buried, burial chambers and tombs not only have limited ventilation if any, they have decaying… well, people. Decaying organisms put off CO2. This can make the places people were buried a pocket of death in more ways than one. Other organisms include vegetation. If a silo was not well kept and the corn started to decay, say after and apocalypse, this could cause the silo to contain large amounts of CO2. 

Last are forest fires. These make large amounts of CO2, on top of the deadly flames. I remember watching what was supposedly a true story once where some firefighters were being overtaken by flames and they hid in a cave. They all lost consciousness, but did live in the long run, an interesting twist. 

Now, let’s cover the man-made sources. First up is combustion. This includes wood, coal, gas, etc. that are burned in poorly ventilated areas. These can be used for heating, lighting, cooking, to boil water for washing laundry, warming bath water, and more. 

I have lived in homes where I didn’t worry about using a wood stove in it because it was so drafty. I have also had a carbon dioxide detector in other homes. And yes, it normally went off a couple times per winter. We would open the doors and windows, no matter how cold it was, for an hour or two to air the home out. this is not the recommended fire department method, as they would tell you to let them handle it. 

The fermentation of alcohol and food is another source. Historically, this was done in basements, and even caves. As we already covered, these do not always have the best ventilation. However, there are many historical records of wine houses making ventilation, so if you have specific eras or places you’re writing, you might need to do a little research. 

We have all been to Halloween things where dry ice was used to make fog. What few know is that the process of converting from a solid to a gas leads to a build up of CO2 if it is not in a well-ventilated area. Anyone else seeing the use of ventilation theme? I’m half afraid someone is going to put a warning sticker on my back. 

There is some equipment that uses CO2 as well. I will cover a couple, but if your character works with chemicals, I suggest researching them. First, Co2 is used as a shielding gas in some welding processes. Simply put, it is to get to keep the oxygen out of the welded area while it hardens to make a stronger weld. 

Some chemicals manufacturing can cause CO2. There is also the danger of making CO2 if certain chemicals are mixed together. It’s illegal where I live to tell you which ones. Again, if your character is working with chemicals, do a little research on them. 

There are some post-apocalyptic possibilities. On top of everything already said, collapsed buildings or underground bunkers could have compromised ventilation. Whether the ventilation pipe of a bunker is bend, or a building fell making it sealed off, this is a dangerous situation for your character. CO2 will inevitably build up, and they will need to find a way to get fresh air in, or risk the consequences. 

Unmonitored industrial sites are another danger. Some industrial sites used CO2 in their manufacturing and the container will inevitably fail. This will be dangerous to anyone nearby and could leak into low-lying areas around the site. 

So now that we know where CO2 comes from, let’s cover the signs and symptoms of CO2 poisoning for your characters. These include, 

* Headaches

* Dizziness

* Nausea

* Fatigue

* Confusion

* Weakness

* Drowsiness

* Feeling flush

* Shortness of breath 

* Hyperventilation

* Chest pains

* Fast heart rate

* Disorientation

* Paranoia 

* Visual disturbances (My favorite example is seeing ghosts) 

* Panic attacks

* Tingling in the limbs

* Twitching 

* Loss of muscle coordination

* Fainting

* Seizures or convulsions 

* Coma

* Death 

What should your character do if they (or likely another character) believe they have CO2 poisoning? Great question! No matter what you are writing, the first aid is to first remove them from the area with the CO2 and into fresh air. This could be tricky depending on how far they need to go to get to fresh air, and the levels of CO2. Death pockets are called that because they lack the oxygen that your character needs to survive. 

Once they are in fresh air, your character can sit upright if they are conscious and breathing well. If they feel dizzy, lying down would be safest. However, if they are unconscious, they should be placed on their side in what is called the recovery position. This is lying on their side so they do not choke if they become ill. Whichever side is fine, unless the character is pregnant, and then the left side is best, so the baby doesn’t compress any major blood vessels leading to circulation issues. 

In historical times, many people believed that fanning a person would help to get oxygen to the lungs better. This could also be used as someone trying to help while waiting for an ambulance in modern times. It could also be used after an apocalypse. 

In modern times, the victim of CO2 poisoning is given oxygen, and in severe cases, oxygen therapy is used. Oxygen, in this case, refers to the mask with oxygen placed over the face. Oxygen therapy is when a person is placed in a sealed area with up to 100% oxygen, based on the patient’s needs. From my research, it looks like the first recorded case of oxygen being used in a hospital setting was in 1885. This became fairly common in hospitals in a 1930s and 1940s. Portable tanks were invented and used in ambulances during the 1950s. The first home oxygen tanks were made in the 1950s, but it was in the 1960s and 1970s that they became more common in the home. 

To sum up, CO2 poisoning can be used in and for many types of stories. It makes for amazing suspense and is the perfect way to show not tell. The tension of something being wrong but they don’t know what, or finding people dead with no seeable reason for their deaths. This would be very powerful in a story. If everyone dies going into one spot, it could easily lead to superstitions about the spot, or even outright fear. 

It can be a great mystery. Why are people dying? Or maybe there is only enough CO2 to make symptoms but not kill anyone. Perhaps it is used in a murder plot, or to prove someone’s innocence. There are a plethora of ways this can be incorporated, so get creative and have some fun with it. 

Fun fact: Dry ice is CO2 at an extremely low temperature. 

One quick reminder before we get to all the ways things could go wrong in your story. To help others find this content, pop on over to Apple podcasts and leave me a review. Or if you are watching on YouTube, drop me a comment and say hello, or ask a question. This is the best way to help others find my content. 

Now, for everyone’s favorite part, what could possibly go wrong in your story? 

Likely to go wrong: Your character is in a home that is well insulated. They are using a fire place, and develop a headache. They don’t realize it is CO2 build up. 

Likely to go wrong: Your animal character went to a hot spring to get a drink only to be surrounded by CO2. If they don’t leave soon, this could be deadly. 

Possible to go wrong: A container of CO2 is punctured at an industrial site. Everyone will need to evacuate quickly or this could be deadly. 

Possible to go wrong: Your character is exploring a cave and holds a torch out to make sure they do not go into deadly gas. When the torch suddenly goes out, it is so dark that they can’t find their way out. If no one comes looking for them, this could be deadly. 

Unlikely to go wrong: Your character starts seeing ghost whenever they are in their home overnight. They never see them when they first come home from work. They have no idea it is CO2 poisoning. 

Unlikely to go wrong: Your character is close to a volcano when it erupts and sends out a plume of CO2. This could be deadly. 

Improbable but still technically in the realm of possibilities: Your character is sailing in the ocean when there is lake overturn. CO2 envelopes their ship. This could be deadly. 

Improbable but still technically in the realm of possibilities: A volcano erupts, letting out large amounts of CO2. This settles in the valley below, and kills off entire villages and eco systems. 

Now, for the announcement you have all been waiting for. I am excited to announce a new companion book series for this podcast. If you’ve been enjoying the deep dives we’ve taken together here on Writing Rural With Alley, then get ready, because I’ve bundled some of your favorite topics into something truly special: a book! Introducing The Writer’s Guide to Rural Life, Volume One.

This book takes the essence of several podcast episodes and transforms them into an ultimate guide for crafting rural stories that feel alive, authentic, and full of depth. It’s packed with survival techniques, food preservation, fire starting, shelter building, and so much more. But this isn’t just another how-to book—it’s a unique mix of historical nuggets, apocalyptic predictions, personal stories, modern insights, with a dash of humor, if I do say so myself.

The “what could possibly go wrong” section has been reworked into a one-of-a-kind probability index to spark your creativity. The index offers challenges for your characters to tackle—whether they’re in the midst of character development, plot twists, or comedic disasters. Whether you are asking ‘what could realistically happen’ or ‘what could hilariously go wrong,’ you’ll find endless story inspiration to help you explore, imagine, and create like never before. 

The Writer’s Guide to Rural Life, with Probability Index, is available on all platforms now. Don’t miss your chance to add this to your library of writing resources. Stay tuned for the release date of The Writer’s Guide to Rural Life Volume Two in the coming weeks. 

Thanks for listening! Until next time, happy wordsmithing.