Are fog machines safe?

We find fog machines in many parties and in every club. They are particularly liked by DJs in order to improve their lighting effects. But are fog machines completely safe? Is the smoke dangerous to inhale?

Fog machines are completely safe as long the machine is used properly with the correct fluid. Indeed the fluid, made of water and propylene glycol is considered harmless when heated at the right temperature. The current state of scientific research also show no confirmed correlation with asthma. 

If you want more information and some recommendations in order to operate your machine safely, then this article is just about that! 

First, please note I will focus on fog machines used by DJs. Like the hurricane by chauvet (I own one, great machine!) or a more generic one like this one . These are the machines that create a white fog in the entire height of your room. I will not talk about the machines that create a thick fog that stays at ground level. Now that is said, how can fog machines be bad for you?

How does fog machines work?

In order to understand the possible dangerosity of a fog machine, one must understand how a fog machine work. A fog machine needs a specific fluid, made of glycol or glycerin mixed with water. It pumps it, heats it and then release the compressed result into the air. 

An image showing the pump and the heater of a fog machine.

If the fluid is under heated, it will result in slippy residue over the floor, which may bother your guests or even be dangerous do dance on. If overheated however, that may create unhealthy byproducts which is not safe to breath.

The vaporization temperature of the fluid may vary depending of the ingredients used, so it is recommended to use the fluid compatible with your machine. In that sense, it is advised to use a low flying fog fluid with a low flying fog machine (the ones where the fog stays at floor level). So do not mix the two types of fluid!

What fluids should be avoided to operate safely?

When using a regular fog machine, try to avoid the “high density fog”. By reading the label, you will see that these are often for low flying fog machines. The production composition being different, your machine may under or overheat the fluid.

Also avoid the colorized fluids. They are fancy in their bottle but completely useless. The smoke will not be colorized and you will probably have a bad smell instead. On top of that, we don’t really know if the additional product is harmful or not, like with e-cigarettes. If you focus on the white fluids, most of them have the same ingredients. Of course the safest way is to use the fluid recommended by the machine manufacturer. Doing so, you are sure that the machine heat the fluid to the exact temperature of vaporization needed for that particular fluid composition. 

Any advice to use a fog machine safely and avoid issues?

Do not empty the remaining fluid back into your fluid bottle. Let the fluid in the machine with the cap properly closed. Indeed, when moving your fluid in and out each time, you may pollute your fluid. That pollution may “soot” your machine pump which may break it. It happened to me with my first machine. With my second one I never removed the remaining fluid of my machine and it lasted longer than my previous one. Moreover, you do not know if that pollution may be harmful or not when heated. So just let the fluid in there, it’s safer!

When your DJ gig is finished, the best thing to do is releasing the heated fluid by pushing the button and then shut down the apparatus right after. This way you don’t have heated fluid remaining in the machine. Don’t overdo it by letting the button pressed and making your machine makes strange noises. I understand that you want to release everything to the last drop, but you may harm the pump this way. Indeed, when there is no fluid left, your machine may pump dust out of the air. This dust may clog the pump and your machine becomes faulty. Just release the fog as you would normally do during the event and let the fluid in the reservoir!

Please note that it is not necessary to regularly clean your machine like some recommend. Only do it if your machine is clogged. Use de-ionized water or fog machine cleaner. I personally prefer not to use vinegar. Sure it is efficient but I believe the acidity may harm internal parts, so to me it is the last resort if the other products did not work.

Are fog machines safe to breathe?

Fog fluids are not carcinogenic and do not cause immediate respiratory problems. Unlike liquid nitrogen low fog effects, regular fog machine fluids do not remove the oxygen in its surrounding. For this reason, regular fog machines are safe to breathe.

Regarding glycol – the only compound used with water – several studies [1] confirm it can cause irritations to the throat (and in rare cases eyes) after long exposure. This is the reason why it is not recommended to use too much fog around singers, especially opera singers. As a DJ, I never experienced throat problems myself and no one complained to me about that. I never noticed someone cough because of the fog either.

Do fog machines affect asthma?

Regarding the risk of asthma, the research is not clear enough to that day. Indeed, many studies can be found about e-cigarettes which also contains propylene glycol as the primary compound. But e-cigarettes also has nicotines and others compounds. Therefore, studies made on e-cigarettes cannot be extended to fog machines.

Some studies on VOC, Volatile Organic Compounds, which focus more on the raw chemicals such as propylene glycol, do not show clear evidence about propylene glycol developing asthma. Indeed the European Respiratory Society (ERS), studied 278 researches on the possibility of VOC causing asthma in healthy people or triggering asthma in already affected people. Their conclusion is that it is not possible to draw any conclusion on VOC causing or triggering asthma.

However, one of these study did show conclusive effect of propylene glycol as a cause of asthma when exposed very young (toddlers and preschoolers). The research has studied the bedrooms of childrens polluted in propylene glycol (PG) used in paints and solvents and seems very confident about their results. However, one study is not enough to draw any cause-consequence conclusion. That’s why the ERS says there is no direct proof yet. Moreover the study focused on children that were exposed to these compound everyday. The relatively low exposure due to fog machines is therefore probably much less harmful for DJS; if harmful it is to begin with.

Regarding my personal experience, I never saw someone starting a asthma attack around smoke machines. Two of my asthmatic friends – which comes regularly to my parties – never complained once. 

What are the other concerns regarding the safety of fog machines?

Well, fog machines gets hot, so make sure to put it somewhere people cannot touch. Childrens love the smoke and believe me, they will try to get near the nozzle. You don’t want them to burn themselves and then have to deal with angry parents. For the same reason, let room around it so it is ventilated enough and do not put anything on the machine that can start a fire. Therefore, the best place is probably under the DJ booth and behind enough so no one can touch it.



Owner and writer of DJ Roundabout. DJing is my passion since 2008. I like all aspects of DJing: mixing but also the more technical aspects: Lights, Speakers, DVS, etc. I even made my own light effects with a home theatre projector!

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