What is a Fog Machine?

Michael Pollick
Michael Pollick

A fog machine is a device that uses a superheated mixture of glycol and water to generate a supply of fog-like smoke. A DJ working at a nightclub might use one to enhance the lighting display behind and above the dancers. Movie set designers routinely use commercial-grade machines to create an ominous atmosphere during a nighttime scene. Every Halloween, amateur party planners pull one out in order to scare their guests or simulate a graveyard experience.

A fog machine.
A fog machine.

The simplest form of fog machine does not involve heating elements or the water/glycol mixture called "fog juice." Instead, blocks of dry ice are dropped into waiting buckets of water, causing massive amounts of carbon dioxide and water vapor to form. This fog could be allowed to fill up a room naturally or could be coaxed along by fans. The water vapor itself is perfectly harmless, although the dry ice must be handled with gloves to prevent painful freezer burn.

A DJ might use a fog machine in a club.
A DJ might use a fog machine in a club.

Commercial fog machines work on a very different premise. When oil on a stove overheats, the result is often a smoky fog, although vegetable oil would not make a promising ingredient in a fog machine. Through experimentation, inventors settled on a mix of water and glycol as the safest catalyst for smoke (fog) generation. A typical machine has a small reservoir or tank that holds a supply of the fog juice. An electric pump draws the liquid over a heating coil inside the device, and when the atomized fog juice becomes overheated, the result is an odorless white smoke. A nozzle on the front of the machine directs this smoke into the outside air.

A fog machine is sometimes used on movie sets.
A fog machine is sometimes used on movie sets.

The generated smoke is not considered toxic, but those with pre-existing breathing troubles may want to avoid prolonged contact. Sometimes, the sight of smoke-filled air can trigger a psychosomatic reaction.

Those who invest in a fog machine for Halloween might also want to experiment with different fog effects. Fog from dry ice tends to hug the ground, but fog generated by machine may head directly into the air. This effect may work well with lighting, but it won't creep into the room menacingly. An accessory called a fog chiller can be placed on top of the device to cool the smoke quickly, which will allow it to creep along the ground like dry ice fog.

Fog can also be piped into other areas through the use of large flexible tubing and small fans, and it can also appear to come out of the ground through an irrigating pipe with a series of holes. Nothing should be attached directly to the heated nozzle of a fog machine, but tubes can be placed a short distance in front to catch the vapor. Users should try to keep the device a few feet (about 1 meter) away from visitors, since the smoke comes out hot for a few seconds.

A fog machine may be used in a nightclub to enhance lighting around the dancers.
A fog machine may be used in a nightclub to enhance lighting around the dancers.
Michael Pollick
Michael Pollick

A regular EasyTechJunkie contributor, Michael enjoys doing research in order to satisfy his wide-ranging curiosity about a variety of arcane topics. Before becoming a professional writer, Michael worked as an English tutor, poet, voice-over artist, and DJ.

You might also Like

Discussion Comments


I currently work as sound/DJ at a nightclub in Brooklyn. I have been there for two months and have been sick three times since. I am wondering if fog is the cause. I am currently trying to figure what brand is used. I eat really well and didn't get sick much before this. I will get a chest tightness and raspy voice the night of and then get sick after a few days. I'll be OK for a couple weeks, but then it happens again. It's driving me crazy.


I'm asthmatic. I have and carry a prescription inhaler, plus I have an eye condition. In some clubs in San Francisco, a few zealous DJs shoot fog/smoke from overhead. Nothing is achieved, no elegance and it's excessive. the DJs have an attitude. If you say something, they smirk, blast it and turn the music up. They have ruined many night, and many of us just don't go any more, but have written to the Board of Supervisors seeking an ordnance covering all clubs stating "No smoke/fog machines shell be permitted in the club if DJ music is played. They are permitted only for live concerts or outdoor events. The use of one will bring a fine of $250 for each occurrence."


I'm guessing there may be a problem with the glycol contained in the fog juice used in clubs. The standard dry ice kind of fog doesn't seem to affect a lot of people with breathing problems, except for the fact you're breathing in carbon dioxide instead of fresh air. But the glycol burns and smokes because of a heating element, so it makes sense that some people would be more sensitive to it.

I once worked for a karaoke company, and one of the clubs we worked had a smoke/fog machine near the dance floor. I hit the button a few times and a thick layer of smoke poured out of a nozzle near the karaoke host's disc player. He was not happy about getting hit with that much smoke all at once, but it really didn't affect the singers standing a few feet away.


@giddion – You are not alone. Some people tell me it's all in my head, but any time I go to an event where even a small fog machine is being used, I have an asthma attack.

I also cough for hours afterward. It's almost as bad as when I have bronchitis, but thankfully, it goes away by the next day.

I stay as far away from fog machines as possible. If I'm trapped in a big room where one is being used, I go to the back of the room or go outdoors until the fog has subsided.

Even if it is all mental, it happens, regardless of the cause. So, I simply have to avoid fog machines.


Does anyone else feel sick when exposed to smoke or fog machines? Every time I'm around one, my chest gets tight and I have a coughing fit.


@kylee07drg – I think this is a trick best reserved for Halloween. I know a DJ with a fog machine, and he uses it way too frequently. It isn't a novelty anymore.

Personally, I don't like going to a club and being inundated with smoke. I was so thrilled when smoking in clubs was finally banned, so I don't want to be confronted with another form of it against my will!

I have no problem with fog machines at Halloween parties. However, when you use one every weekend, it becomes gimmicky and just plain lame.


Halloween fog machines can make really creepy effects! I had a neighbor who rented one to create a spooky environment in her yard for trick-or-treaters, and believe me, it worked!

I didn't see the machine at first, and I wondered why her yard was full of fog when mine was so clear. I figured it out when I accompanied my daughter to the door and I saw the machine hidden behind a bush.

Post your comments
Forgot password?