Smoke? Fog? Fire? All in a night’s work on Broadway. Recently I attended a hazardous material training session sponsored by Local 829 of the United Scenic Artists. I was joined by Broadway Theatre Rep Ed Tilghman.

There has been concern lately at a couple of Broadway shows over the use of smoke and pyro effects. As a result Local 802 has formed a Health and Safety Committee. Tilghman has been researching the problems and the hazardous material (or “haz-mat”) session was a first step.

The class was made up mostly of scenic artists, and this class was very useful to them. They work with chemical substances on a daily basis.

For those of us who were musicians or other theatre workers, it was eye-opening and fascinating.

We learned how different substances travel through the air, how they act upon the human body, their routes of entry and their long- and short-term effects.

For example, some chemicals can be absorbed directly through the skin and into the bloodstream.

Other substances are inhaled or enter the sinuses on dust or mist particles.

The way a chemical enters the body, its toxicity, the amount ingested, and how long you are exposed to it, all determine how dangerous a substance is.

One way to gauge how safe – or dangerous – a substance is, is to consult its Material Safety Data Sheet.

MSDS’s are an industry standard way to communicate the risks and dangers of a chemical product and what precautions one should take while using it. They contain information based on past testing.

Employers are required to have on file all MSDS’s for every type of chemical that is used and stored in a workplace.

In a theatre this could include paints, solvents and cleaning solutions, as well as stage effects such as mist, haze, fog, smoke and pyro.

One common type of fog effect uses a chemical called “MDG Neutral Fluid.” According to its MSDS, it is a mineral oil based fluid that appears fairly safe, although it is classified as a lung irritant and “slightly hazardous in case of inhalation.” There are no carcinogenic effects classified or listed by various safety and standards organizations and “repeated or prolonged exposure is not known to aggravate [a] medical condition.” First aid measures call for washing your skin with soap and water and getting fresh air for prolonged inhalation. As far as chemicals go, not a biggie.

But the MSDS only tells you what is known from past testing. You have to be very careful when reading it. For example, being “slightly hazardous in case of inhalation” is referring to acute health effects – meaning after a large exposure at one time – and has no bearing on the daily, prolonged exposure that a musician might get in a theatre.

Under “chronic health effects” the MSDS has no carcinogenic effects listed or classified for this mineral oil smoke. But this only means that the substance is untested for carcinogenic effects, not that it has no carcinogenic effects at all. And what about the effects of prolonged exposure if you have a pre-existing medical condition? Again, unknown.

The bottom line is that we don’t know how safe these substances are over time because there is no data.

We see that it may be fairly safe in the short term, but when musicians play the same show, breathing in the same effects, on a daily basis over the course of years, the effect is not known.

The best solution is to avoid breathing a stage effect, but that is impossible for pit musicians who are stuck in their chairs for the duration of the show.

Proper ventilation would solve the problem, but it would probably kill the effect also.

A real dialogue needs to be established with productions that use stage effects, because the long-term effect may be harming us.

If you have a health and safety issue at your job, make sure that you make it known to a union rep.

Walter Usiatynski is the percussionist on “Hairspray.” He is co-chair of the Broadway Theatre Committee and also serves on the Broadway Health and Safety Committee.