Hazers vs. Dry Ice--Health Risk

Are smoke machines and/or hazers a health or safety risk?

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I'm a Performance Production freshmen at Cornish College of the Arts in Seattle, Washington and I'm doing a report on the possible health risks of exposure to smoke and haze. Singers especially are wary of singing when a smoke machine or a hazer is ebing used on stage and they will only let them use dry ice.

I was just looking for opinions that I may use in my report. Whether they be different brands that work better or anything.

This is all ver preliminary and I may ask people to fill out a questionaire later on.

Any help would be greatly appreciated!!

Thank you,
Michael DellaValle


Each effect is meant for something different. Yes, hazers can mess with a vocalists throat, but it all depends on the hazer, the juice used . . . DF-50's are standards in concerts, though i have seem a lot of LeMatre g300s and h300's, though the radience has started to make is way in as well . . . fills a giant club here with a very even haze, didnt even know it was there. Water based haze juice is always a plus.

Now as far as foggers go, dry ice is always pretty much harmless . . . . until a choreographer decides to have dancers come up from a thick fog . . . thing to remeber, dry ice is CO2, so you cant breathe in it, so the dancers passed out . . . funny . . .dumb, but funny.


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Premium Member
I have heard rumours that if a machine burns the fluid too hot it will become carcinogenic. I do not know how true this is but in general, they are supposed to be pretty safe. I personally wouldn’t want to be breathing the output in for extended periods of time. Always worries me when I see people inhale a mouthful of fog so that they can then blow smoke rings.

I know that asthmatics get worried by the smoke but I have never seen anyone have an asthma attack induced by the use of a smoke machine. Some people cough but often that is a reflex action.

There were also some older machines that were collected up and destroyed some time back because they were found to be carcinogenic. I cannot recall the exact circumstances but someone else may be able to comment.

We were designed to breath in Oxygen, so anything that competes with oxygen in bonding to haemoglobin can’t be good for you.

Why don’t you do a survey of people and see what their perceptions of smoke/haze use is. I think it would be a pretty interesting survey to conduct. Would be even better to have one sample group coming from an non-cigarette smoking venue/gig and the other coming from a smoking venue/gig. My bet is there is a more negative result from the smoking group.


Well-Known Member
Check out the White Paper published by U.S.I.T.T. on the subject of fog and haze on performers.

It will give you all the information and research you need.


Active Member
Here is my opinion based on my reaserch.

Smoke machine

glycol based fluid (common name water based fog fluid) it makes your throat dry and causes caughing, there are no long term effets proven yet. but there are short term effects. such as dry throat iratated eyes nose and throat.


oil cracker. - leaves a mess but is realitvly ok for the body no proven long term effects. does not cause dry throat. but makes a mess for the sound and video guys.

glycol based fluid (common name water based haze fluid) it makes your throat dry and causes caughing, there are no long term effets proven yet. but there are short term effects. such as dry throat iratated eyes nose and throat.

there is no such thing as a water based haze fluid because it wouldnt work there needs to be glycol which is an acahol in it. and we all know that alchol drys out your skin and since your breathing it in it drys your throat.

Dry ice.

this is a grey area in my opinion this is the most lethal of them all dry ice is pure C02 which if not used properly could kill your entire audiance and those sitting in the orchestra pit. there is a huge misconception that because something is natural that it wont kill you well they are wrong the most deadly things are natural elements. dry ice has short term and long term effects

short term - dizyness, fatigue, light headedness

Long term - Brain damage, Death

i do not understand why people demand dry ice is safe it is not ventilation is the key to any dry ice or nitrogen fog effect and theatres esspecialy ones in comunity centers and schools are netorius for bad venting. so i think you need to reflect this in your paper



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Premium Member
Bill - do you have a link to that paper at all?

I neglected to comment on CO2 but Jon is on the ball with his comments. People have been killed (recently) in compartment fires where CO2 has been used for fire controll.

In fire control, CO2 dispurses the oxygen, starving the fire. If you have ever had to put out a fire using CO2 you will know that you have to keep a good spray on it for a decent period of time.

In a confined area (such as the engine room in which several Navy crew died), the oxygen supply would have been finite and consumed not only by the fire but the crew as well. The introduction of CO2 would have then made it hard (if not impossible) to breath in the remaining oxygen in the room.

However, I doubt whether it is as big a problem in a large area like a theatre, where you can move away from the source of CO2. It would be a problem if it was forced at your face for an period of time.

Otherwise, its use would be much more regulated. Although, this is based purely upon my understanding of the use of CO2.


Active Member
The size of the area isn’t the issue its weather it’s ventilated. A large room with co2 is just as bad as a small one. The only difference is the concentration of co2 and Oxygen atoms it might not kill you but could seriously affect your health and not just short term were talking long term damage.

If you don’t believe me just as one other person said lay on the floor while running a dry ice machine, see how light headed you get. Eventually you will pass out.

If you need the effect fine but double check the ventilation in the room make sure the pit is protected and the orchestra seats in the audience are not going to be affected.

Dry ice is not a safe alternative it is merely another option, dry ice is regulated in certain parts of the country it has warning labels when sold to the public and should come with an instruction sheet. These warn you of the effects of dry ice but people hear ice and think water they see safety.

its interesting the reactions of coughing you get when you put on a hazer, but dry ice is the only one that is really suffocating you, people just whisper to there friend oh I know what that is its dry ice I bought some for my son Johnny last Halloween. They don’t cough or get up and leave.

It’s a strange phenomenon


Active Member
To get information on exposure to glycols (and mineral oils), go to the National Institute for Occupational Safety and Health (NIOSH) website and search the site http://www.cdc.gov/niosh/homepage.html ). NIOSH is under the Center of Disease Control. NIOSH does research and develops exposure guidelines. (There may also be guidelines from the American Conference of Government Industrial Hygienists [ACGIH].) Other agencies (for example OSHA) use NIOSH guidelines in their enforcement rules.

The AEA study, "Health Effects Evaluation of Theatrical Smoke, Haze, and Pyrotechnics" (June 2000) (available at the AEA website) concluded in part:

"No evidence of serious health effects was found to be associated with exposure to any of the theatrical effects evaluated in this study". [Italics are mine.]

"Peak exposures to elevated localized air concentrations following a release of glycol smoke are associated with increased reporting of respiratory, throat, and nasal symptoms, and findings of vocal cord inflammation."

"Elevated exposures to mineral oil haze are associated with increased reporting of throat symptoms."

"…it is recommended that exposures to these materials by Actors performing in musical productions not exceed peak or ceiling concentrations of 40 mg/cubic meter for glycols and 25 mg/cubic meters for mineral oil. Time weighted average exposures to mineral oil should be kept below 5 mg/cubic meter…"

I skimmed through the AEA paper and the focus appears to be on actors, rather than stage crew. The study was conducted at the request of the AEA and League of American Theaters and Producers. I suspect that stage crew is more likely to experience long-term exposure primarily because a venue could perform a series of productions, each with fog/haze effects, but with a different group of actors for each production. An actor could go from show to show with varying degrees of fog/haze, if any. Not to mention the fact the stage crew will be more likely to be exposed for every use, while only some actors are exposed. (Actors/crew on a long tour, of course, would have the greatest total exposure.)

(Carbon dioxide / dry ice was not evaluated in the AEA study because none of the shows involved appeared to be using it.)



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Premium Member
Thanks for the links Joe.

Jon - I hear what you are saying and I agree - hence the use of the word finite, implicating a lack of ventilation. However, the ability to move away from the source is just as important as ventilation. Someone being force fed CO2 in an open field is just as screwed as someone in an unventilated room if they cannot move away from the source.

Had to use a CO2 fire extinguisher to put out a motorcycle stunt rider some months ago and had to be real careful of not filling his helmet with it. This was in an open air arena with a decent breeze blowing.


Active Member
It appears that the fog/haze studies focus on the chemical types, not the carbon dioxide, so I decided to take a look into it.

Some notes about carbon dioxide can be found at NIOSH.



5,000 ppm TWA
30,000 ppm STEL
40,000 ppm IDLH

Current OSHA PEL:
5,000 ppm TWA

REL - NIOSH recommended exposure limit.
TWA - indicates a time-weighted average concentration for up to a 10-hour workday during a 40-hour workweek.
STEL - short-term exposure limit; unless noted otherwise, the STEL is a 15-minute TWA exposure that should not be exceeded at any time during a workday.
IDLH - Immediately Dangerous to Life and Health.
PEL - OSHA permissible exposure limit (This is enforceable).
ppm – parts per million (by volume).

Now, what do these numbers mean in terms of a mass of carbon dioxide. For example, how much dry ice? Assuming that a large theatre will have at least some nominal ventilation, the TWA number probably isn't an issue because the short term use of the dry ice will get "turned over" in a relatively short time, even a few hours. So, I'll focus on the STEL and the IDLH since the fog effect is probably a short time.

The density of carbon dioxide (gas) is about 0.12 lb/cubic feet. The STEL is 30,000 ppm and converting that to a percent - 30,000/1,000,000 x 100 = 3%. Now, I'm going to make an assumption that the carbon dioxide will mix with the air. Arguable, but it’s a conservative assumption because I'm trying to estimate the smallest amount that could be a problem. I'm also going to assume a small area (20 feet x 20 feet, a small stage area) to be conservative and only consider it to a height of 6 feet above the floor (Few people are taller than that).

So the volume affected is 20' x 20' x 6' = 2,400 cubic feet.

At 3 % carbon dioxide, that’s 72 cubic feet of carbon dioxide, and at 0.12 lb per cubic feet, that's 8.6 lb of dry ice carbon dioxide. (Someone else is going to have to comment on how much dry ice is used for an effect or a scene.)

For the IDLH 40,000 ppm is 4%, so the quantity is 20' x 20' x 6' x 4/100 x 0.12 = 11.5 lb.

But for a more realistic quantity because there is air movement, consider a larger stage, say 30 feet wide and 30 feet deep, but still use 6 feet high, the amount that would reach the STEL is:

30' x 30' x 6' x 3/100 x 0.12 = 19.4 lb.

Again, a very conservative estimate.



Kind of an interesting aspect: When doing a show at the Dorothy Chandler Pavilion in Los Angles this year, I was talking to some of the resident crew who works with the LA Opera. The Opera has put into effect new rules completely forbiding the use of haze in their productions BECAUSE of health risks. So now they own several, high quality MDG hazers that they have no use for. The only fog that they are allowed to use is Dry Ice, which obviously is not a worthy substitiute. Just thought I would share that.



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Solution to the "drowning the crew and orchestra with CO2" problem: Black SCBA equiptment.


Active Member
did you mean to say scuba? otherwise whats

"Black SCBA equiptment"

it is really sad that people have been convinced that hazers are bad but hey its their money were just there to make the lights look pretty and i guess we just need to find a new way to do it.

May i propose that we just put two guys on the catwalk with dusty chalk board erasers banging them together during the show. ofcourse the performers hair and coustumes will be white by the end of the night but hey cant complain about the health aspect. the only reaction to this method might be some soothing effects to hart burn.



Active Member
Radman said:
Solution to the "drowning the crew and orchestra with CO2" problem: Black SCBA equiptment.

Although the playing the brass and woodwinds will be a little problematic…. :wink:

SCBA - Self Contained Breathing Apparatus

(Like what firemen and hazardous materials workers wear. I think the "U" in SCUBA is "underwater", but the purpose is similar. Just don't take SCBA under water because I don't think they are designed for pressures other than atmospheric.)

Judging by the AEA (Actors Equity Association) report, short term voice problems are often reported by performers when fog/haze effects are used. If the performers can't deliver, that's a problem.

AEA agreements have a say in the use of fog and haze effects. There are numerous agreements posted on the AEA site. For example, one agreement only permits the use of "dry ice, liquid nitrogen, and substances listed in and in accordance with the specified limits set forth in Equipment Based Guidelines for the Use of Theatrical Smoke and Haze" (an AEA document). [That's from a LORT (League of Residence Theatres) agreement.] While I didn't look at them all, another agreement only permitted dry ice and liquid nitrogen; it had no provision for other substances.

The AEA Stage Manager Packet includes a "Theatrical Smoke and Haze Report" that must be submitted to AEA before the official opening to ensure that AEA guidelines are being followed. The form also includes a section titled "List any symptoms suffered by Actors and/or Stage Managers" that has a list of symptoms that can be checked off.

I'm not sure what IATSE has to say about this. Because their work is essentially traditional trade union work, they may defer directly to OSHA and other work rules with no special fog/haze/smoke rules.

Now, I suspect that the average reader of this forum isn't affected by AEA agreements (or any other professional agreements for that matter), but it's good to know that these limitations exist. Many fog/haze effects that are being used in high school and college productions may not be allowable in many professional productions.




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Premium Member
I like your thinking Jon - make them suffer long term effects of local pockets of inflammation of the airways and lungs from inhalation of chalk particles and then smoke/haze will seem like a walk in the park!

Besides, 2 kids with chalk board erasers tend not to be DMX compliant! Although you could rig up a cue light for them.

You could also change the colour of the chalk dust - perhaps coloured dust could replace the need for gel?

I think you are on a winner here!!


Active Member
I got busy during the holidays and forgot to post this.

As I expected, IATSE has been just as interested in this issue as AEA. The IATSE has a number of safety bulletins on their website, and one concerns this subject. The title of this particular bulletin uses the term "guidelines" and I am not sure what weight that carries. (For example, how restrictive is the phrase "should not".) A footnote at the bottom of the bulletin refers the reader to other sources.

In any case, Safety Bulletin 10 (Guidelines Regarding the Use of Artificially Created Smokes, Fogs, and Lighting Effects, October 1999) says (in part):

"1. The following substances should not be used:

c) Ethylene glycol and Diethylene Glycol;
d) Mineral oils;…

2. The following substances may be used:
a) Propylene glycol, Butylene glycol, Polyethylene glycol, and Triethylene glycol…
b) Glycerin products…
c) Cryogenic gases (e.g. carbon dioxide, liquid nitrogen)…"


By the way, ESTA also has information on the subject, including a testing protocol. And there is a great deal of information buried in this site.



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