# Hazers vs. Dry Ice--Health Risk



## TheTheaterImp

Hi, 
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


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## drumbum

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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## Mayhem

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.


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## BillESC

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.


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## jwl868

There is also a couple of reports on the Actors Equity Website, in their Document Library, under "Safe and Sanitary"

http://www.actorsequity.org/home.html


Joe


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## jonhirsh

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. 


hazer

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 


JH


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## Mayhem

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.


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## jonhirsh

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


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## jwl868

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.)


Joe


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## Mayhem

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.


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## jonhirsh

Yah thats a realy good point, i didnt mention it because the original poster was speaking about


TheTheaterImp said:


> when a smoke machine or a hazer is ebing used on stage



not in an open field but yah good point.


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## Mayhem

jonhirsh said:


> Yah thats a realy good point, i didnt mention it because the original poster was speaking about
> 
> 
> TheTheaterImp said:
> 
> 
> 
> when a smoke machine or a hazer is ebing used on stage
> 
> 
> 
> 
> not in an open field but yah good point.
Click to expand...


They could be doing the sound of music


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## jonhirsh

:wink: you got me again  

JH


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## jwl868

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.

http://www.cdc.gov/niosh/76-194.html

http://www.cdc.gov/niosh/npg/npgd0103.html

NIOSH REL: 
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.


Joe


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## LDSFX

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.

-Nick


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## Radman

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


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## jonhirsh

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. 

JH


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## jwl868

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.


http://www.actorsequity.org/home.html



Joe


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## Mayhem

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!!


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## jwl868

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)…"

http://www.iatse-intl.org/services/bulletins/SftyBull10.pdf



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.

http://www.esta.org/tsp/safety/fog.html



Joe


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## len

This is just like the "will atmospherics set off fire alarms" threads. There's no clear cut answer because there are too many factors involved; airflow, room size, capacity of HVAC, output and type of atmospheric, etc. 

Many years ago I did a school dance with 2 F-100 foggers. A small group of kids decided it would be fun to stick their faces directly into the flow of the output literally inches from the nozzle and they got sick from it. I shot some video of them doing it, then told them to stop. The parents tried to sue me, until I sent their lawyer the video of the kids doing this. The lawyer backed off because he knew he didn't have a case. 

Also, since then I've barricaded atmospherics better, thanks for asking.


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## jonhirsh

"This is just like the "will atmospherics set off fire alarms" threads. There's no clear cut answer because there are too many factors involved; airflow, room size, capacity of HVAC, output and type of atmospheric, etc."


There is a clear cut answer, people just dont like the answer so they make argue the point. Designers dont like being told there atomospherics are bothering the performers and actors dont like being told its harmeless. 

We all know it is an issue and is not harmless but atmospherics look better then none and we will keep lying to actors about the dangers and actors will continue to protest but this does not mean there is no clear cut answer what it means is people are just being stupid. 

JH


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## Mayhem

Sometime last year I posted a response to a different, yet parallel topic. Unfortunately, I have not been able to link to it, as I cannot locate it.

In that post there were several good links and I followed a few of them up and found on that actually conducted medical exams of actors before and after performances and also asked for their perceptions on how the smoke affected them. Where most other studies just ask the actors about how they feel.

The main finding was that there was no medical evidence to suggest that the use of smoke/haze/pyrotechnic smoke actually caused any physical changes in their upper airways, vocal cords or eyes (the main symptomatic areas reported in previous studies).

The main factors involved with reported symptoms were:
* number of performances per day; 
* physical demands of their role;
* vocal demands of their role and;
* stress associated with the performance.

The study found that an actor that was physically and vocally challenged in a play with smoke reported similar symptoms when the play was performed without smoke. Likewise, an actor in a fairly stress free part listed few symptoms regardless of whether or not smoke was used.

From what I have read, this is the only study that has taken into account the actual physiological changes and not simply based its conclusions on the subjective feedback of the actors. 

It seemed that the presence of smoke was a psychological stimulus for the actors and blamed as the cause for certain symptoms. What appears to actually happen is that in two similar shows and roles (in terms of physical and vocal workload), the show that used some form of smoke/haze was no different in physical effects to the actors than a similar (or possibly the same) show in which no smoke/haze was used.

Whilst Jon raises a good point about the manipulation of the facts to achieve a desired result, I think that it is important to note that in many cases the issues may be related either to the smell or a conditioned response that smoke is bad for you. After all, any fire training / public information will advise you to drop to the floor and crawl to avoid smoke inhalation, as it is toxic and most people that die in a fire do so from smoke inhalation. Yet here we are telling them it is (relatively) safe. Now if I was an actor, I would probably believe the fire department and health authorities that tell me smoke is bad over a tech telling me that this is a different smoke that is safe.

Just another slant on things.


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## koncept

isnt fire smoke different than haze and fog. given that most fog/haze is water based????


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## jonhirsh

koncept said:


> isnt fire smoke different than haze and fog. given that most fog/haze is water based????



Some properties are differnt but dont let someone lie to you "water" based fog may be based on water but it has a high content of glycol which is an alcahol (not water) hazers use oil based fluid but there are "water" based ones but there not as great (this is up for debate) just to prove a bit of a point about the whole its not water thing if you run out of haze fluid for a water based hazer you can fill it with antifreeze and will get the desierd effect but it wont smell great. 

That study you speak of the medical one is a study of long term effects not short term if i remember corectly. I think long term i would argue that there is damage done but it is so minute that we dont notice it. but short term i have seen actors go to the hospital and needing a resporator affter a show. they had a Asthma attack.


JH


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## Mayhem

koncept - yes, you are correct but my point was that most people will assume that smoke is smoke.

Jon - nope, the study looked at the short-term effects. Actors were examined before and after each performance. A long-term follow up study would be interesting but difficult and expensive. It could take 30 to 40 years before the effects were known but bases upon the data collected and through comparison with other known variables they should be able to make some reasonable predictions.


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## soundman

jonhirsh said:


> Some properties are differnt but dont let someone lie to you "water" based fog may be based on water but it has a high content of glycol which is an alcahol (not water) hazers use oil based fluid but there are "water" based ones but there not as great (this is up for debate) just to prove a bit of a point about the whole its not water thing if you run out of haze fluid for a water based hazer you can fill it with antifreeze and will get the desierd effect but it wont smell great.
> 
> JH



whats the MSDS for vaporized antifreeze? I dont think it is something I would want to expose many people to.


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## jonhirsh

Hmm probabaly no worse then haze fluid lol  

I know its been done and I have been envolved with a show that did it and im still alive. 

 
JH


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## Mayhem

jonhirsh said:


> Hmm probabaly no worse then haze fluid lol
> I know its been done and I have been envolved with a show that did it and im still alive.
> 
> JH



[action=Mayhem]thinks this answers alot of my questions about you Jon [/action]

Ooops - I only thought that, didn't type it. ****, this new forum can read minds!!


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## jonhirsh

Ha good work very whitty lol... 

just for future reference any questions needing answerd about me or my history in the theatre you just need to ask. 

JH


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## soundop

one factor i havent seen is how many tims during a show and how quickly you can get it out of the theater


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## nez

i have to say that i will agree with the singers they are annoying cuz they can some times make you cough or eritate your eyes but they are in no way harmful to you or else they would not be sold in the first place and o yea they can also set your fire alarms off lol


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## saxman0317

jonhirsh said:


> 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.
> 
> 
> hazer
> 
> 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
> 
> 
> JH



i think your getting CO confused with CO2. Dry ice produces CO2 which is compleatly harmless to the body unless it is purly CO2 that you breath with no oxygen (O2) what soever. And in all honestey, its only something like 4% O2 in the air at any given time anyways, and u dont use near that much to breath..CPR 101.. So, unless you pumping dry ice into the aud for 4 days straight with everything sealed up and a full house, your going to be ok.

BUT!!!! CO is very harmful, with the effects that you stated above. This is formed from the incompleate combustion of fuel(such as bad burning gas heaters, hot water tanks, etc.) This is far from CO2 and only a few parts per million are enough to cause permanent damage. Chances are though, theres not much of a cause for CO poisioning in a play, at least that we can control, but if there is, your going to have actors and audience puking everywhere long before something serious happens which should be enough of a warning to get everyone out.


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## Chris15

saxman0317 said:


> i think your getting CO confused with CO2. Dry ice produces CO2 which is compleatly harmless to the body unless it is purly CO2 that you breath with no oxygen (O2) what soever. And in all honestey, its only something like 4% O2 in the air at any given time anyways, and u dont use near that much to breath..CPR 101.. So, unless you pumping dry ice into the aud for 4 days straight with everything sealed up and a full house, your going to be ok.
> 
> BUT!!!! CO is very harmful, with the effects that you stated above. This is formed from the incompleate combustion of fuel(such as bad burning gas heaters, hot water tanks, etc.) This is far from CO2 and only a few parts per million are enough to cause permanent damage. Chances are though, theres not much of a cause for CO poisioning in a play, at least that we can control, but if there is, your going to have actors and audience puking everywhere long before something serious happens which should be enough of a warning to get everyone out.



If I recall correctly, there is 21% oxygen in the atmosphere. I would think that excess CO2 could cause problems. If I recall my chemistry right, it would cause the equilibrium in our blood stream. There is a series of buffer reactions that occur to maintain constant pH levels in the bloodstream, as biochemical processes will only occur when the pH is between 7.35 and 7.45.

The first buffer is H2CO3 + H20 <=> H3O+ = HCO3-. Now H2CO3 is formed when CO2 and H2O combine. So more CO2 leads to more carbonic acid which lead to more of the acidic hydronium ion. 

The second is HHb+ (Haemoglobin) + 4O2 + H2O <=> Hb(O2)4 (Oxyhaemoglobin) + H3O+. Since there is an increase in hydronium ion, the equilibrium will shift by Le Chatelier's principle to produce more O2. This would seem like a good thing, but in fact it is the opposite since the oxygen cannot reach the cells. It needs to be oxyhaemglobin to travel through the blood stream.

This is a simplified version of the process, but it should help to explain why CO2 inhalation is dangerous. The fact that CO2 is heavier than air means that it stays low to the ground. This is often uses for effect but it also means that there are high levels of CO2 close to the ground, though since gas does eventually rise, it will likely rise right up into the nostrils of the performer.

CO possesses it own safety risks and it is important not to confuse CO and Co2, but it needs to be recognised that CO2 does poses risks and these need to be acknowledged and managed as part of the risk assessment process as part of Occupational Health and Safety.


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## Mayhem

Well stated Chris – I think Saxman is confused with the amount of Oxygen that our body uses. On average, we breath out about 16% oxygen, which is why EAR (expired air resuscitation) works. Buffering and pH disequilibrium is not the main issues however. CO2 will bond to the haemoglobin molecules more readily than oxygen will, so the more CO2 you breathe in, the less oxygen you will actually get into your blood stream. This is what will kill you.


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## saxman0317

While you are right, carbonic acid is not typically a problem unless it is mixed with water some how. You lungs can handle carbonic acid very well, go to a city and thats mostly all you can breath. BUT...my precentages were wrong, i checked that out, but i was right in the fact that you dont use near as much as is there, and at the same time, when it hugs the ground, you still need to pump a whole lot into a room for it to get to the point of being dangorous. I cant see people lying on the floor for long periods of time during a show. An aud, etc is a loarge space with lots of cubic yards of air...what ever a few dry ice cues set off probaly wont even amount to a couple cubic yards of CO2, nothing near fatal in any of our aspects.


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## saxman0317

Chris15 said:


> If I recall correctly, there is 21% oxygen in the atmosphere. I would think that excess CO2 could cause problems. If I recall my chemistry right, it would cause the equilibrium in our blood stream. There is a series of buffer reactions that occur to maintain constant pH levels in the bloodstream, as biochemical processes will only occur when the pH is between 7.35 and 7.45.
> 
> The first buffer is H2CO3 + H20 <=> H3O+ = HCO3-. Now H2CO3 is formed when CO2 and H2O combine. So more CO2 leads to more carbonic acid which lead to more of the acidic hydronium ion.
> 
> The second is HHb+ (Haemoglobin) + 4O2 + H2O <=> Hb(O2)4 (Oxyhaemoglobin) + H3O+. Since there is an increase in hydronium ion, the equilibrium will shift by Le Chatelier's principle to produce more O2. This would seem like a good thing, but in fact it is the opposite since the oxygen cannot reach the cells. It needs to be oxyhaemglobin to travel through the blood stream.
> 
> This is a simplified version of the process, but it should help to explain why CO2 inhalation is dangerous. The fact that CO2 is heavier than air means that it stays low to the ground. This is often uses for effect but it also means that there are high levels of CO2 close to the ground, though since gas does eventually rise, it will likely rise right up into the nostrils of the performer.
> 
> CO possesses it own safety risks and it is important not to confuse CO and Co2, but it needs to be recognised that CO2 does poses risks and these need to be acknowledged and managed as part of the risk assessment process as part of Occupational Health and Safety.



i wasnt saying CO2 is compleatly safe, im just saying in this setting, with this amount being released, theres not going to be much of an effect. Im deffinatly going for more of the reasonable risks, and not the what if way out there chances. Technially, too much O2 will kill you to, but we wont get into that one because theres not much of a chance of the carbon being scrubbed out through the lights, even though that can happen


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## Chris15

I was using the equilibria as a means of showing where my conclusions came from. They are not central to the effect, rather a means of getting there. As Mayhem said, CO2 will deprive the body of oxygen. I think that it would be fair to say that too much of anything can kill you. More likely things will kill you if there is a sudden change in concentration. For instance, someone who has experienced carbon monoxide poisoning requires oxygen. But giving them this oxygen can also do them harm.

With your comments on carbonic acid and water. Consider that the plasma is your blood is 96% water.

Dry Ice as well as any other type of fog / haze effect can set off fire alarms, but that is a separate issue.

The greatest danger, as has been previously said is to those at a lower level. If for instance, you have an orchestra pit and you use a large amount of dry ice, you will create a fair amount of gaseous CO2. Since CO2 has a tendency to sink, the CO2 will generally reach higher concentrations in this area. Then the risk of asphyxiation to those in the pit etc. significantly increases.


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## saxman0317

But also for that reason of sinking, its not going to set of the alarms as well, which it shouldnt anyways. Personally, i wanted to get purly heat change rate detectors in our aud, but they were to expensive. Then it wouldnt matter what we used. But either way, i dont know if it was in this one or another, never turn off and alarm no matter what type your using. Better to have to evaq the stage or not have an effect that have a subphonia on you for a felony, right?


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## Chris15

saxman0317 said:


> But also for that reason of sinking, its not going to set of the alarms as well, which it shouldnt anyways. Personally, i wanted to get purly heat change rate detectors in our aud, but they were to expensive. Then it wouldnt matter what we used. But either way, i dont know if it was in this one or another, never turn off and alarm no matter what type your using. Better to have to evaq the stage or not have an effect that have a subphonia on you for a felony, right?



I was talking to someone in the theatre complex locally and they said that they have had it whereby the dry ice fog was so good that it went into the foyer. I suspect that the ceiling in the foyer would be lower than in the auditorium and thus the detectors would trigger more easily.

As has been said here, you should isolate the fire alarms in the theatre. You do not want to evacuate the theatre and you certainly do not want to be sending false alarms to the fire brigade. Here you get billed AU$500 for a false call out. Plus if you have a show that runs for a number of nights and you are triggering the alarm each night and you have a genuine fire in another part of the building, the boy who cried wolf effect comes into play. The fire brigade are unlikely to respond and your building burns down. 

By all means if you can show me legislation that makes the isolation of sectors on a fire alarms blanketly illegal, by all means produce it but until that time I maintain that it is perfectly legal to have the fire alarm isolated. Check with your maintenance department. Someone has to be permitted to isolate, though in some instances it may be that the fire brigade has to do it.


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## jwl868

I know its an old thread, but I thought it would be worth keeping the continuity.

I was at the AEA (Actor's Equity) website to see if they had any new safety publications and I found two:

AEA recently updated two documents in February 2007 regarding the use of haze:

Smoke and Haze Testing - Calibration Factors

Smoke and Haze Testing - Time and Distance Guidelines

http://www.actorsequity.org/library/library.asp?cat=33


Joe


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## gafftaper

Just want to point out that both chemical and C02 fog is completely safe if you don't breathe.

Thanks for the new info and bringing this thread back it's an important topic that needs to recycle occasionally. I think the CO2 is especially important because it's so cool... but it's also easy to loose control of the fog. Newbies often don't realize just how dangerous that could be.


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## astrotechie

gafftaper said:


> Just want to point out that both chemical and C02 fog is completely safe if you don't breathe.


_
Well beside that also. If you make the fog machine and/or dry ice fill up the room in excess to make the normal balance between O2 and CO2 change so that there is more CO2, there is a problem there.
But otherwise there is no problem with either of them unless the smoke effect from either method sets off the smoke detectors_


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## soundlight

Well, the smoke/fog from lower end "fog machines" can mess with your health and/or vocal performance ability. Just stand in the fog from one for a few minutes and you'll know what I mean...


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## gafftaper

astrotechie said:


> _
> Well beside that also. If you make the fog machine and/or dry ice fill up the room in excess to make the normal balance between O2 and CO2 change so that there is more CO2, there is a problem there.
> But otherwise there is no problem with either of them unless the smoke effect from either method sets off the smoke detectors_



Yeah there have been lots of problems in the past with low quality chemical fog machines that have created serious long term health effects. Today it's more temporary effects but either way you don't want to try to act in the middle of bad chemical fog. It probably won't kill you any more but it might make you sick for a while. I believe there are very few foggers/hazers that Actor's Equity has endorsed as safe. If you work in an equity house your actors might walk if you use the wrong machine and fluid. 

As far as the CO2 it doesn't take as much as you would think. You don't have to alter the balance of CO2/O2 in the room as you suggested. All you need is a normal proscenium stage that sits up above the audience a few feet. Flood the stage real good with dry ice fog and it rolls off the front of the stage and fills the audience or pit. Remember that Co2 fog is more dense and colder than the O2. As it fills that area, it displaces the O2 that's in that area. If you are a little over zealous you can easily fill up those first low rows (or the orchestra pit). With fog. Once it's full of fog... it's also empty of O2... and that's bad. 

An even more likely hazard is the actor who "passes out" or "plays dead" on stage in a low lying layer of CO2 fog just might not get back up.


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## Van

I ran across an interesting post on the web a wile back when doing research for our recent poroduction of _Metamorphses._ It was from a school in Illinois somewhere near Chicago I believe. They < the highschool > were having big issues with using water on stage < don't get me started on that particular point> Anyway they were approached by a local company that specialies in Nitrogen fog systems. apparently they filled thier "pool" with nitrogen fog and then had the kids move in and out of it instead of water. I think it's a great idea and would be a cool effect, but I also can't beleive the school signed off on it as far as saftey considerations are concerned. Too much time under that fog and there would be a bunch of dead highschool actors. Nitrogen fog is Much better at displacing O2 in an area than either co2 fog or chemicalfogs.


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## koncept

that just sounds like a lawsuit waiting to happen...


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## icewolf08

jwl868 said:


> I know its an old thread, but I thought it would be worth keeping the continuity.
> I was at the AEA (Actor's Equity) website to see if they had any new safety publications and I found two:
> AEA recently updated two documents in February 2007 regarding the use of haze:
> Smoke and Haze Testing - Calibration Factors
> Smoke and Haze Testing - Time and Distance Guidelines
> http://www.actorsequity.org/library/library.asp?cat=33
> Joe



We have been doing a lot of research in the Equity rules on smoke and haze effects here at my theatre in preparation for our production of Les Mis. If I remember correctly, it was the Broadway production of Mis that started a lot of the testing that AEA has been doing. I find it interesting that they make no mention of CO2 fog or of smoke released from pyro.

It is my understanding that unless you are taking your afternoon nap lying on stage in CO2 fog it actually poses less of a health risk than most fog and haze machines. You have to use so much CO2 fog to fill a stage that has a 40' proscenium opening with a release point even 10-15' upstage of plaster. By the time that fog makes it over the lip of the stage it starts dissipating pretty well. I have to assume that if CO2 fog posed any risk to members of a pit orchestra (as it tries to find the lowest point in the theatre) then the musicians union would make some kind of fuss about it, or request hazard pay for working shows with CO2 fog. By the same token, if it posed any risks to the audience I am sure there is some other organization that would make a fuss.


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## koncept

it almost seems like the pit is the place to have it go regardless of musicians and then have a separeate ventilation system there to exhaust it out or the pit using a couple of fans and some duct work...


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## TimMiller

OK i may be repeating some of the things that people have already said but here is the big rundown.

OIL BASED HAZE

Oil based haze sets off carbon monoxide alarms, and all new buildings are equipped with carbon monoxide alarms. They haze up sensors in smoke alarms and proximity detectors also. They are just messy all the way around. They also aren't great for your lungs so they should be used moderately. With oil based haze a little goes a long way.

NOW FOR OIL BASED HAZERS
IE... DF50 and some others. They now do make a water based haze for most oil based hazers b/c of pressure from buildings and the health dept.

Water based haze/FOG
Water based haze is basically humidity. Some machines can make a mess if not used properly or if it leaks so any problems should be taken care of to minimize a big mess. Water based fluid is almost impossible to clean up once it is all over the stage. A side effect to excessive water based haze is drying of the mouth, but it would take a bit of haze to cause that.

CO2 Fog (Dry ICE)
One common mistake is when people see low lying fog they immediately assume it is CO2. There are lots of water based low lying foggers on the market these days. When using dry ice you have to use the appropriate amount for the room b/c it is pure CO2 and people cannot breathe CO2 very well. I have never ran into a problem of having someone pass out due to too much dry ice but i have heard first hand stories of people using dry ice in a very confined space. But i would say for the most part if you use some common sense you will be safe.

Now for the complainers.
Water based and oil based haze. When people complain they cannot breathe or are asthmatic that is because of a psychological reaction and not an actual reaction to the smoke.

With CO2 you do have to be a little more careful bc once i did have a kid have an asthma attack.


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## jwl868

Van said:


> Anyway they were approached by a local company that specialies in Nitrogen fog systems. apparently they filled thier "pool" with nitrogen fog and then had the kids move in and out of it instead of water. I think it's a great idea and would be a cool effect, but I also can't beleive the school signed off on it as far as saftey considerations are concerned. Too much time under that fog and there would be a bunch of dead highschool actors. Nitrogen fog is Much better at displacing O2 in an area than either co2 fog or chemicalfogs.



An important difference between nitrogen and carbon dioxide is that while both gases will displace air and massive quantities of either will cause asphyxiation, carbon dioxide (but not nitrogen) has OSHA concentration limits in air. That is, there is a concentration above which will cause a physical problem, other than asphyxiation. Apparently, there is no maximum nitrogen concentration (other than that which displaces so much air or dilutes out so much oxygen thus causing asphyxiation). (Considering that air is about 79% nitrogen, perhaps this isn’t a surprise.)

Perhaps that is why that pool effect used the liquid nitrogen, although I agree, using it in a confined space like that seems risky and potentially dangerous. No doubt they had a professional system that was fail-safe. 

A link for NIOSH’s carbon dioxide information:

http://www.cdc.gov/niosh/npg/npgd0103.html


Joe


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