Tag Archives: OSHA

Smell is Irrelevant

“This doesn’t smell bad so I don’t need a respirator.” I hear that from time to time, either from students or in online forums. Prop makers working with chemicals use their sense of smell to determine how dangerous something is. “This smells better than that, so I don’t use that anymore.” “I can’t smell a thing, so this must be safe.”

No no no. This is dangerous, and the wrong way to think about safety with chemicals.

For every chemical, OSHA sets limits as to how much you can be exposed to. They try to figure out the amount you can be exposed to while working with something your entire life, and never have adverse health effects from it. These are called Threshold Limit Values (TLV).

The first is  the time-weighted average (TWA). The TWA is meant to indicate what you are constantly exposed to at work. They measure the average amount you are exposed to over an 8-hour day and a 40 hour week. (Uh oh, we often work much more than that in theatre).

Next is the short-term exposure. or STEL. They define this as 15 minutes of exposure. And you have to have an hour break before the next exposure. And you can only have four exposures per day.

Finally there is the ceiling value. You should never reach this level of exposure, even for an instant. They also have IDLH, which is “immediately dangerous to life and health”. Instant exposure at this amount will kill or irreversibly affect your health.

So let’s look at the following chart, which has the TLVs for some common chemicals found in the props shop. You probably recognize some of these as ingredients in paints and coatings. Amines are found in many epoxies. Methyl ethyl ketone is used in polyester resin. The diisocyanates (TDI and MDI) are two of the more common curing agents used in two-part polyurethanes.

All the values are measured in parts per million (ppm), which means out of a million pieces of air, that is how many pieces are of the substance being measured (for comparison, room air has 209,500 ppm of oxygen).

Odor thresholds and Threshold Limit Values of certain chemicals

So where does smell come in? Well, every chemical has an “odor threshold”. This is the amount, again in ppm, of a chemical at which point you can smell it. This is much less standardized, because it can be hard to test and different people have different sensitivities to smell. The number is often given in a range. You can see in the chart that the odor thresholds are all over the place for the different chemicals.

I’ve pulled a few chemicals out and put them in a chart so you can see what’s happening a bit easier.

 

Chart for OT and TLV

Look at chlorine. The odor threshold is way below the TLV TWA. This means that even if you smell chlorine, you may not be exposed to a harmful amount. You may be able to smell chlorine all day every day and still not have harmful effects (like if you work at an indoor pool).

Now look at formaldehyde. The short-term exposure limit (the orange dot) is way down in the graph. The odor threshold is way at the top. That means you can be exposed to a harmful amount before smelling it. In fact, you will have to be exposed to three times the threshold limit before you can smell it. So if you are working with something that off-gasses formaldehyde (including many plywoods and engineered lumber, VOC-containing paints, and even some fabrics), you cannot assume you are safe because you do not smell anything.

Look at the two diisocyanates (MDI and TDI). Both of them also have an odor threshold above their short-term exposure limit. If you look back at the chart, you will see that the STEL for MDI is also its ceiling value, which is the amount you should not exceed even for an instant. And its odor threshold is twenty times higher than that. You can be breathing dangerous and even deadly amounts of MDI before you even get close to smelling it.

This is why many people suggest casting urethane parts inside a fume hood or a spray booth; even a respirator is not a reliable protector. One way to tell if your respirator has stopped working is if you can smell the outside air. But with these chemicals, you cannot smell them even when they are present in dangerous amounts. So you have no indication of whether your respirator is working or not.

Your nose is a great sensor for many chemicals, but you should never rely solely on it for your safety. You need to know about the specific chemicals you are working with and how their odor threshold relates to their threshold limit values. No more, “this doesn’t smell bad so I don’t need a respirator.”

Smell you later.

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.

Review: Health and Safety Guide for Film, TV, and Theater by Monona Rossol

The Health and Safety Guide for Film, TV, and TheaterIt’s difficult for me to write a review about the Health and Safety Guide for Film, TV, and Theater (Second Edition) by Monona Rossol for several reasons:

  1. The information inside is mandatory.
  2. No other book is dedicated to this information.
  3. Monona Rossol has been teaching health and safety to theatres since at least 1986 and is uniquely qualified to write this book.

So rather than a review, this is more of an introduction about being aware of your own health and safety, and an encouragement to read this book and act on the information contained within. This goes for those working professionally, as well as the growing number of hobbyist prop makers (I would say especially for hobbyist prop makers).

I’ve attended Monona’s safety seminars three times, and even with this book, I am still learning about the hazards we face in our line of work and the precautions we need to take. Luckily, she uses a very factual and empirical approach with this book. Rather than present her personal opinions, she discusses what the laws and regulations are. She will also present the various studies done where she feels the laws don’t go far enough in protecting workers. This is perhaps one of the more striking lessons to take from this book or her seminars; as stringent as we may feel OSHA is, the dangers we face remain woefully understudied, and manufacturers have great latitude to push untested chemicals on the market or provide misleading safety claims on their labels.

You’ll notice the mention of OSHA above. This book is very much grounded in the legalities of working in the United States. Though she may occasionally mention regulations in Canada, the UK or Europe, her focus remains firmly enmeshed in US law. Unfortunately, there is no real equivalent to this book outside of the US. All is not lost for my international readers, though. Since US laws protecting workers are among the most lax in the developed world, this book can be seen as presenting the absolute minimum guidelines for protecting yourself on the job.

While the book does deal with electrical safety, shop safety, fall hazards and other areas of physical danger, the majority deals with materials and chemicals and the less-understood danger of chronic exposure. We all know that you should avoid chemicals that could instantly kill you if you accidentally breathe them. What is far less understood is the result of your body somehow absorbing a myriad of chemicals and products throughout the day and over the years you are in the workforce. Some of these can live in your body for years, reacting in unknown ways with all of your genes and the other chemicals present in your body. Steve McQueen died from mesothelioma at a time when asbestos was used frequently in the theatre and film industry for painting and prop making; what are you being exposed to?

If you’ve never given thought to any of this, this book will be overwhelming in the information it provides. You may think we are safer these days with our stronger laws and new products. After all, lead paint only comes from China and we don’t use crazy materials like Celastic anymore. But as Monona points out, lead has only been banned in indoor house paint; it can still be found in any number of industrial paints. Some filling materials and putties were still being taken from a mine which contained asbestos as late as 1998. We are also exposed to far more chemicals on a daily basis than our fore-bearers in the past. Every one of us is already carrying a certain amount of mercury, dioxin, PCBs and countless other chemicals in the tissues of our body (known as our total body burden); scientists estimate we carry as many as 700 contaminants regardless of where we live in the world. Any additional chemicals we add from our work place enter that toxic soup and can have all sorts of additive or synergistic effects. So it’s even more important for us to monitor what we use than it was for our grandparents.

This second edition is long overdue; the first edition came out over 11 years ago in 2000. Monona includes many of the important changes to the laws as well as advancements in the science behind the effects of the chemicals (both of which have a lot owed to Monona’s own tireless work), and the addition of new types of products in the marketplace, such as nanoparticles. Unfortunately, the through-line remains the same: companies don’t want to spend money on safety training, manufacturers add more toxic products to the market, scientists can’t afford to study even a small percentage of their effects on the body, and governments refuse to pass stronger laws or give their agencies the power to enforce existing ones.

Until all that changes, though, we have this book. Read it and use it.

The Right Proper Links

These are so cool: US bread wrappers of the 40s and 50s. Besides being tons of fun, the pictures are good enough to print out if you need to make period wrapped bread. Incidentally, the site this is from, How to be a Retronaut, is chock-full of the most wonderful vintage and historical pictures. You can waste hours of time on this site while rationalizing that you are “doing research.”

I’ve pointed to the Early Office Museum site before, but I just found this gallery of Really Big Stuff. It’s photographs of early office equipment, like typewriters and rubber stamps, constructed at large scales (think “parade float” size). It’s also a good opportunity to check out the site if you haven’t heard of it before.

The NIOSH Pocket Guide to Chemical Hazards is an extremely useful source of information for the hundreds of chemicals listed as “hazardous” by OSHA and found in the stuff we build props out of. Rather than serve as an exhaustive guide to all information, it lists key information about each chemical relevant to work. You can view it online or download the whole thing as a PDF; I’m also throwing the link up in the sidebar of this site so you can find it every time you visit.

The Historic Naval Ships Association has a 1949 training manual titled Engine Room Tools presented in full on their website. It illustrates and describes the tools one would find on a ship at the time, namely metal-working hand tools. They are surprisingly similar to the metal-working tools you would find in a props shop, and the illustrations demonstrating their use are very cool.