Tag Archives: CAS

Know What Chemicals You Are Working With

This past week, we learned that Gordon Billings, a UK props master, died from exposure to asbestos. Billings had suffered from shortness of breath and coughing for awhile, and passed away from lung cancer this past August. It was not until last week that the coroner issued his ruling that Billings’ death was due to asbestos exposure.

As a props master, Billings worked on films such as Empire of the Sun and TV series like The Sweeney. Part of his job was sweeping dust and debris from derelict buildings used as sets. Before his death, he had made a witness statement that he was not aware he was being exposed to asbestos.

As props people, we may be exposed to toxins, poisons and harmful chemicals on a daily basis. We may not even be aware of what we are exposing ourselves to. The harm from some of these chemicals may not manifest themselves for years, or even decades, after being exposed.

We may be smart about the particularly nasty chemicals; the ones that smell really bad and that have warnings all over their labels. But those chemicals that we only use once or twice a year may not cause as much harm as those which we subject ourselves to every day. Many harmful chemicals do not even have an odor, or give an indication that we are being exposed. As with Billings, you cannot tell whether you are breathing asbestos or whether you are just inhaling dust. The two-part polyurethanes we use in molding and casting have little to no odor, yet can be some of the more toxic chemicals you come into contact with in a props shop. Cleaners such as Simple Green or any of the “natural” cleaners which have “Orange” in the name can actually contain chemicals which cause reproductive problems, organ damage and even cancer, if you use them without gloves or adequate ventilation. The list goes on.

Protecting yourself from harmful exposure to chemicals is one area of safety where you cannot rely on assumptions or so-called “common sense”. Adequate protection can only come from gathering as much information about the products you use, and building the correct safety infrastructure to deal with them.

For every product in your props shop, you should have an MSDS which lists all hazardous ingredients and what safeguards should be taken. You can also find MSDS for the individual ingredients if you wanted more information. Websites such as the Chemical Abstracts Service and Toxipedia can guide you to more information about various chemicals. And, of course, Monona Rossol’s book, The Health and Safety Guide for Film, TV, and Theater is a must-read for anyone working in our industry.

It is one of the great downfalls of our industry that this kind of information is not taught as consistently or in-depth as it needs to be. Even when the desire to have a safe workplace is there, the knowledge of what that means, or the funds to make that happen are often lacking. A visit from OSHA can certainly point out all the dangers in a shop space, but the fear is that the company will be hit with steep fines or even shut down. One of my dreams is to have some kind of funded organization that could audit shop spaces for their safety infrastructure without fear of being reported, and train employees in proper safety procedures. The larger companies can already do this, as can areas with strong union presences, but there still exists so many smaller theatres and ad hoc film production companies with practically no knowledge of safety. Colleges and universities also suffer greatly from a lack of proper precautions, and these are training the next generation of technicians and managers.

Until that happens, it is up to each of us to protect ourselves. Know what chemicals and hazards you are dealing with. You do not want to devote your entire life working like Gordon Billings, only to spend your last years on Earth suffering from health problems.

The Nose Knows Not

I often see a lot of products advertise themselves as “low odor”. I also hear the occasional prop maker mention that one product is safer because it “smells better” than an alternative.

What is smell? Smell means you are detecting airborne particles, fumes, gases, vapors, dusts and mists. And if these tiny airborne things are reaching your nose, than you can be sure some of them are entering your lungs, and from there, your bloodstream. So smelling something is a warning that you may be breathing hazardous substances.

But the smell is not related to the toxicity of that substance. In fact, particularly odorous substances can, in some situations, be safer than their low-odor counterparts. Relying on your sense of smell is a poor method of determining the quality of the air you are breathing and whether you should be wearing a respirator or working in a spray booth. Let’s see why.

First, a brief foray into the world of measuring toxic exposure amounts, as well as how we measure “smell”. You need the MSDS to know what chemicals are in the products you are using and in what quantities.

OSHA measures the amount of a substance in the air using “parts per million”, or PPM. For example, if Chemical X is recorded at 1000 PPM, than for every million atoms of air in a room, one thousand of those are Chemical X. The other 999,000 are probably atoms of oxygen, nitrogen, carbon dioxide, water vapor and so forth.

To determine the safe level that certain chemicals can be worked at without causing harm, OSHA has a number of measurements related to the threshold limit value (TLV). The TLV gives a number in PPM; above that number is harmful, below is not. The TLV is indicated in a number of ways. There is the “ceiling value”, or TLV-C, which is the amount that should never be exceeded. The TLV-C is usually pretty high, because it takes a lot of any single chemical to harm you in one breath. More common is the time-weighted average (TLV-TWA). This gives you the average level of a chemical exposure over a period of time (usually eight hours unless otherwise indicated). 1 This number is far lower than the TLV-C, because you are being continuously exposed to a certain level over an extended time. 2

Let’s look at acetone. Acetone has a TLV-TWA of 500 ppm. That means that over an eight hour day, your body has been harmed in some way if you have breathed, on average, 500 molecules of acetone with every million pieces of air. It may be higher at times—such as when you open a can of acetone—and lower at other times, such as when it has all evaporated and you are working on something else.

Getting back to smell, the other important measurement is the Odor Threshold (OT). This measurement, also in PPM, indicates at what concentration you can smell that particular chemical. Acetone has an OT of 62 PPM.

Let’s see what happens. You are in your shop working with acetone. It fills the air at 30 PPM. You keep working with it. It is now 62 PPM; you start to get a whiff of that distinctive acetone smell. “Uh oh.” you think. “Better open a window and set some fans up.” The increased ventilation brings the concentration of acetone back down to 50 PPM. You no longer smell it. During this whole time, your exposure to acetone never even gets close to 500 PPM because the smell alerts you to the fact that you are being exposed; you smell it in a concentration far below what is dangerous to breath.

Now let us look at another chemical common in the props shop. Hexane (or n-hexane) is used as a solvent, and is found in some cleaners and degreasers, as well as in adhesives, particularly fast-drying glues or cements intended for leather. Hexane has  a TLV-TWA of 50 PPM and an OT of 130 PPM.

Let’s step through another typical day. It’s the morning and you are gluing some leather together. Your exposure to hexane creeps up to 80 PPM for a few minutes. You clean something off with a hexane-containing cleaner and the concentration of hexane goes up to 100 PPM. You work on something else for a few hours and the level of hexane drops to 10 PPM as it evaporates. In the afternoon, you are using some rubber cement and white-out (both of which typically contain hexane) and your exposure goes back up to 60 PPM. In fact, by the end of the day, your average exposure (your TLV-TWA) has been around 55 PPM—above the limit of 50 PPM, meaning you inhaled a harmful amount. However, the level never even approached the OT of 130 PPM, so you never smelled it.

In other words, if you relied on your sense of smell to warn you of dangerous chemical exposure, it would have failed you in this case.

Any chemical with an OT above its TLV-TWA will not warn you with its scent before you are exposed to dangerous levels. Some chemicals lack any adequate warning signs for overexposure. The cyanates used in polyurethanes popularly used in molding and casting are particularly egregious. For instance, Methylene diphenyl diisocyanate (MDI) is commonly found in two-part rigid polyurethanes and polyurethane foam. Though one of the least toxic of the isocyanates, it still causes harm at low levels 3. Exposure can also create sensitization or allergies, which leads to violent or even fatal reactions in workers exposed to even a small amount. The TWA is only 0.005 PPM (the PEL is actually 0.02 PPM, but that is a ceiling limit). The OT has not even been established, but you can be expected to have some warning in the form of eye and nose irritation around 0.05 to 0.1 PPM. 4 In other words, you may not have any warning until you have been exposed to at least ten times over the amount that is safe to breathe over eight hours, or even five times the maximum amount you should breathe at any one time. Even then, you may not correlate your runny nose or watery eyes to the polyurethane; it has no distinctive smell, so you may just continue on, thinking “Hey, this is great. It doesn’t smell bad, so it must be safe to breathe.”

That’s wrong. Dead wrong.

Notes:

  1. You will also run across the PEL (Permissible Exposure Limit) of a chemical. This is the actual legal limit established by OSHA, above which an employer cannot expose its workers to. You have to check what the PEL is measure in; a TLV-TWA for eight hours is often used, but it may also a shorter exposure time or even a ceiling limit.
  2. Many other organizations have their own standards and measurements, and not every chemical has been measured in every way. So acetone has a TLV-TWA of 500 PPM, but the TLV-C has not been established by OSHA. It does, however have an IDLH (Immediately Dangerous to Life or Health) of 2500 PPM; this is typically a bit stronger than TLV-C, indicating you can probably die with a short exposure (under 30 minutes) at this level.
  3. See this compilation of health hazards of MDI.
  4. Occupational Health Guideline for Methylene Bisphenyl Isocyanate (MDI), US Dept of Health and Human Services, 1978.

Proptober Fest Links

Berkeley Rep has posted a video of the set changes in Chinglish. It’s fun and very well made; I saw Chinglish back on Broadway and the scene changes were slick, fast and fluid. I wish more theatres featured their technical and backstage elements like Berkeley Rep has done here; so much of what we do is underrepresented in the media, and it all just disappears once the show closes.

If you like James Bond, a new website called “The Credits” has a short article on some of the famous gadgets in those 22 films. The website also has a cool story and video on Western Costume, one of the large costume rental houses in Los Angeles.

A blog called “She Creates Stuff” has an interesting technique for aging glass bottles with hardening oil rather than paint; this keeps them food safe so they can still be drunk from (found via the Propnomicon blog).

Of the 68,890,282 chemicals used in business and industry today, only about 900 have been tested for cancer-causing abilities. As props people, we are exposed to many chemicals on a daily basis in our paints, adhesives, cleaning products, molding and casting compounds, coatings and even when cutting solid materials. Many of these chemicals are introduced to products without testing whether they are toxic or cause long-term harm. The Safe Chemicals Act means to amend the current laws so that manufacturers have to test chemicals before they sell them to you, rather than the other way around. Currently, it is languishing in the Senate; you can help push it along by contacting Senator Harry Reid, signing this online petition, or by contacting your own Senator to urge action.

So Many Chemicals in the World

54,973,018. That’s how many registered organic and inorganic substances there were in the world when I wrote this sentence, according to the Chemical Abstracts Service (CAS). The Toxic Substances Control Act (TSCA) gives the EPA in the United States the authority to maintain an inventory of all chemicals used in commerce (excluding chemicals used in foods and food additives, pesticides, drugs, cosmetics, tobacco, nuclear material, or munitions). To date, their inventory contains 84,000 such chemicals. Over 1670 of these are considered hazardous substances which your employer is required to inform you when you are working with them. You’ve probably seen products which state “This product contains a chemical known to the state of California…” There are somewhere in the neighborhood of  750 chemicals listed under California’s Proposition 65 which are known to cause cancer or reproductive toxicity.

Of course, over 78% of the high volume chemicals produced have not had even basic toxicological testing (see Toxic Ignorance, published by the Environmental Defense Fund), let alone testing for carcinogenic properties. “High Volume” of course does not include all 84,000 chemicals used in commerce; in 1990, that list included a mere 2971 chemicals. In other words, around 653 chemicals have been tested for their toxicity by 1990. What a far cry that is  from the 54,980,438 registered chemicals in existence (when I wrote this sentence). Some estimates put the total amount of chemicals tested worldwide for carcinogenic properties at around 900. Nine hundred out of nearly 55 million.

What’s a props person to do? When you look at all the products you use – spray paints, adhesives, epoxies, mold-making and casting, coatings, sealants, resins, foams, cleaners, and so on and so on – and count up all the various chemicals contained within, you could have hundreds of hazardous and carcinogenic substances which you are exposed to on a daily basis. If you wish to make a career of making props, that could mean several decades of exposure. It adds up quickly.

One shouldn’t generalize about safety, because proper safety procedures involve specific actions for specific chemicals. But if one were to distill down the essence of safety it is this: don’t breathe anything but air, and don’t get stuff on you. Always use the least-toxic product in every situation. Often, the only benefit of a more-toxic option is speed, or ease of use. Formula 409 may cut grease faster and with less effort then soap and a scrubber, but soap will not be absorbed through your skin and cause reproductive harm.

In the brief time it took you to read this article, around 24 chemicals have been added to the CAS database. As I write this sentence, the number stands at 54,980,470.