CO2 Fog Machine Special Effects Safety

If you’ve been to a live concert or stage play, one of the coolest effects is fog or smoke on stage. These effects are created using carbon dioxide to create low-lying fog, or glycerin to produce artificial smoke in the air.

Both CO2 fog machines and glycerin smoke machines have their advantages and disadvantages. But since we're CO2Meter, we know about CO2.

CO2 Fog Machine for Halloween

A carbon dioxide fog machine works by quickly releasing frozen or liquid carbon dioxide into the air. As the CO2 expands into a vapor, it condenses the moisture in the air and creates the fog effect.

 CO2 Fog Advantages:

  • Heavier than air, pools on stage or flows like water
  • Quick releasing for instantaneous effect
  • odorless and tasteless
  • quickly dissipates into air

CO2 Fog Disadvantages:

  • Liquid CO2 is expensive and hazardous to transport
  • CO2 gas can displace oxygen in enclosed areas which can pose a health hazard to staff or audiences

The "heavier than air" advantage of CO2 fog is both an advantage and a challenge. If you are trying to achieve the effect of walking on clouds or a bubbling cauldron of liquid, CO2 is the perfect solution. The downside is that because CO2 gas acts like water, it quickly pools in low areas like under the stage. If there is a basement under the stage, assume that is where all the CO2 will end up.

CO2 Fog for Halloween Effects

Just like CO2 used in live concerts and stage plays, CO2 is also used to create many spooky effects like fog, haze, mist or smoke. CO2 fog machines are also popular especially during the spooky Halloween season.

While many homeowners can purchase readily available fog machines for trick-o-treaters, a more cost-effective and simple means is to create your own spooky effects with dry ice!

In creating these spooky effects like those you would see in the movies, the process is quite simple and involves adding dry ice to hot water in an insulated container (adding optional food coloring) and repeating to maintain a truly ghostly scene.

You can read our step-by-step guide on "How to create your own fun CO2 experiment at home" which includes instructions for creating these spooky special effects as mentioned above.

It is incredibly important to remember that while CO2 experiments can provide exceptional fun, excitement, and thrills - ensuring proper CO2 safety guidelines is vital.

More Halloween Fun with CO2

For more Halloween fun with CO2, here's a list of our favorite experiments:

Let's face it, who does not like a smoking pumpkin or a creepy low-lying fog machine effect upon trick-o-treating? It's easy to make your favorite Halloween experiment and gain all the "oohs" and "aahs". Just remember that safety comes first and ensure you and those around you are always protected.

And don't worry. The team at CO2Meter is here to help ensure that your "Spooktacular" special effects are not only fun, but safe too! 

CO2 Fog Machine Safety

While a small rise in CO2 levels is not noticeable or harmful, at concentrations up to 1% (10,000 ppm) it will make some people feel drowsy.

Concentrations between 1% and 5% can cause dizziness, headaches, visual impairment, and unconsciousness in as little as a few minutesAnd according to the National Institute of Occupational Safety and Health (NIOSH) concentrations above 5% (50,000) may cause asphyxiation, even in the presence of sufficient oxygen.

Are CO2 effects equipment safe?

When used properly and according to the manufacturer’s specifications CO2 effects equipment used at event venues or festivities are safe. However, as in any application that uses CO2 in enclosed spaces, human errors can occur. This is also true, for those individuals using dry ice to create experiments - without proper PPE equipment and handling of CO2 in confined spaces, this could involve severe injury.

The following tips are commonly utilized to ensure safe practice when using CO2 special effect products:

  • Always install your CO2 jet or use your CO2 gun at a distance further than 5 feet away from any personnel in the direct line of fire
  • Never shoot your CO2 jet directly into an individuals face for an extended period of time as it will displace ambient air and can cause asphyxiation 
  • Train your employees or any personnel who will be operating the CO2 equipment to use proper technique and understand how to shut off the tank in case of an emergency
  • Utilize an emergency shut off instruction sheet and place near the CO2 tanks
  • CO2 blasts should be approximately 3-5 seconds in duration
  • CO2 should be used in areas with proper ventilation and air circulation
  • We always recommend the use of a CO2 safety monitor

To provide perspective, for those that do not take precaution there are examples of injury from improperly using carbon dioxide such as:

  • A theater technician at the Smokey Mountain Opry Theater in Pigeon Forge, TN experienced an unfortunate fatality while two other technicians were sent to the hospital due to a CO2 gas leak during a performance. Authorities later discovered that a safety valve was left open on the effects equipment.
  • When working with dry ice and special effects a study at the University of Iowa showed that heightened CO2 levels changed the acidity in the brain which plays an essential role in the fear response. Several of the experiments described in the Iowa paper showed that inhaling air with high levels of CO2 triggered strong fear reactions in mice. CO2 levels in any enclosed space will rise naturally over time due to normal human respiration.

What does this mean? For starters, you should always create your experiments or special effects involving dry ice in a properly ventilated space. This is critical because the excess carbon dioxide from the dry ice can pose significant health risks if contained in confined spaces. Do not store dry ice in a home or office freezer as the freezer is not cold enough to maintain the integrity of the dry ice.

Additionally, ensure that you can mitigate any emergencies from occurring by wearing proper PPE equipment (this means - gloves especially when handling dry ice, goggles, and clothing) as well as ensuring portable or fixed CO2 safety monitors are present to protect yourself and those around you.


For those working with dry ice and CO2, our Personal 5% CO2 Safety Monitor (PRO-10) is used.

Personal CO2 Safety Monitor
This personal monitor features real-time CO2 measurements, as well as audible/visual indication should CO2 levels exceed the standard safety threshold. 

Whether you are using CO2 to create magnificent effects during concerts, or providing a low-lying CO2 fog machine effect for Halloween, always remember to have fun but be safe.

For more information on dry ice safety monitors, click here.

Do you have additional questions or concerns on CO2 safety monitoring or special effects? Email us at Sales@CO2Meter.com.


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