That’s Hazardous? Process Safety in Unexpected Places

“If you do not expect the unexpected you will not find it, for it is not to be reached by search or trail.” –Heraclitus

I work for a process safety consulting company and we often participate in community events that bring members of the general public through our door.  The first question we always encounter is “So what exactly is it that you do here?”  The quickest, simplified explanation is that we work with companies in industry to prevent fires, explosions and toxic releases.

As you can imagine, that’s an attention getter.

Almost immediately, the next question is something along the lines of “Like Deepwater Horizon?”  It’s true that part of our work is to prevent the kind of disasters that seem obvious to the public.  Some of our work, however, involves products or materials that you wouldn’t expect to require process safety consulting at all.

I Still Feel New to This

When I started working in process safety, one of the first things I learned is that process safety is applicable to a lot more than I imagined.  I was already aware that the production of gasoline is dangerous and that the West Fertilizer plant explosion in Texas was indicative of the hazards involved in fertilizer production.  What I didn’t expect, however, is the need for process safety in numerous other production processes, many of them for everyday products.  For instance, vinegar is made by sparging air through alcohol, a flammable liquid. Does anyone think that deliberately mixing air with a flammable liquid is without the potential for fire or explosion? Many ordinary products, like diapers and disposable medical devices, are sterilized by treating them with pressurized ethylene oxide. I’ve learned that ethylene oxide is terribly poisonous, which is why it is so good at sterilizing, but that it is also incredibly flammable and explosive.

If you’re an old hand in process safety, this is old news. For those of us who still feel new to process safety, though, it can come as a shock that many ordinary products made with processes that really need process safety.

Sugar and Flour

If you’re reading this, I’m sure you’ve heard of the disaster at Imperial Sugar in Port Wentworth, Georgia when, in 2008, 14 people lost their lives in an explosion at the refinery.  When the news of the explosion broke, I remember thinking to myself “What makes sugar so dangerous?”  I couldn’t imagine a scenario in sugar production that would result in such a large, deadly explosion.

When I began work in process safety, I learned two things about my favorite baking ingredients.  First, process safety applies to sugar and flour production and, second, that the real hazard in sugar and flour production isn’t even what most people consider “chemical.”

Sugar is granulated and conveyed during production; flour is ground and conveyed.  If you’ve ever poured flour or confectioner’s sugar out of a bag, you know that a dust cloud is almost inevitable.  Now, imagine that on a much, much larger scale.  Once products are converted into a fine powder, conveying them sends the tiny particles into the air where they stay suspended until they eventually settle and, if housekeeping procedures aren’t perfect, accumulate.  Any disruption to the accumulated dust disperses it back into the air, where it joins new dust being generated and the cycle starts over again.  If the product can burn, then these fine particles are known as combustible dust and present an explosion hazard.  Once ignited, the deflagration process happens so rapidly that the heated air and gaseous fire products produce extreme air pressure than can blow out walls and destroy structures.

The disaster at Imperial Sugar was the result of a combustible dust explosion.  Equipment on a conveyor belt sparked, resulting in the first explosion that shook the building.  That first blast launched more dust into the air that ignited seconds later, creating a fireball that could be seen from miles away.  While sugar and flour come immediately to mind when considering combustible dust explosions, they are not the only consumer products at risk.  Combustible dust explosion hazards also exist in food, furniture, cosmetics, and tobacco production as well, just to name a few. If something can burn, its dust can explode.

Paper

When I was young, “Save the trees!” was a common protest when someone overused a paper product.  As a seven-year-old, I interpreted this in the most literal sense.  I imagined full trees on a conveyor belt, sliding beneath a saw that sliced the tree into the paper I used in the classroom.  I’m not seven anymore and now know there’s much more to the process.

To make paper from trees, the paper-making process first turns the raw wood into pulp, which is basically tree soup.  It’s up to 99% water.  This can be done mechanically by using machines to grind wood chips into pulp, but it’s more often done chemically, using chemicals like sulphates and sulfites in a process called “kraft”.  If whiter paper is desired, the pulp mixture needs to be bleached.  This can be done with a variety of chemicals, but paper-making processes most often use chlorine compounds.  The pulp then dries and runs through heated rollers before any final touches and cutting the finished paper to size.

Most paper mills are not covered by OSHA’s Process Safety Management standard (PSM) because they don’t have enough of the PSM standard’s listed highly hazardous chemicals to exceed threshold quantities. Just the same, the chemicals they do use are still dangerous.  The compounds that paper mill workers are exposed to have been shown to cause significant respiratory and cardiovascular effects.  Chlorine-based bleaches, for example, can be highly toxic.  They cause breathing difficulties, violent coughing, acute tracheobronchitis, and chemical pneumonia.  Even exposure to relatively low levels can be fatal.  This means preventing a release is important not only to the workers, but also to the community nearby.

So, even if paper mills aren’t covered by the PSM standard, they still need to manage process safety.

Cannabidiol Hemp Processing

If you follow the debate over the legalization of marijuana, cannabidiol (CBD) is probably familiar to you.  It’s a naturally occurring compound in cannabis plants that is desirable to those looking for relief from ailments such as inflammation, pain, anxiety, or seizures, etc. without the side effects of some prescription drugs or the intoxicating effects of smoking marijuana.  Out of curiosity, I was interested to learn more about the extraction process and the process safety hazards it might have.

There are a couple of commonly used methods to extract CBD from marijuana or industrial hemp plants, the ethanol extraction method and the CO2 extraction method. During ethanol extraction, the hemp plant is introduced to ethanol which acts as a solvent to extract cannabinoids. CO2 extraction involves treating marijuana plants in a series of chambers that control temperature and pressure.  The use of ethanol means that fire hazards are present. Although CO2 is not flammable, using it at such high pressures means that catastrophic tank failures—explosions—are a process hazard. Also, since CO2 can displace air, it can become an asphyxiation hazard.

As with any chemical process, CBD oil extraction is safest when performed in a controlled, regulated environment, as it is in a plant that complies with the OSHA PSM standard.  However, CBD oil extraction at home has become a dangerous trend. Home extraction processes often use butane as their solvent. As a result, the number of home explosions blamed on in-home CBD oil extraction has been on the rise.  Whether you just aren’t aware of the risks of the process or you think you’re being safe enough, CBD oil extraction is a process best left to professionals.

Sometimes, When You’d Least Expect It….

Sure, process safety is important in chemical plants and refineries. You don’t have to explain that to anyone. But process safety is important to so many other industries as well.

If you work in process safety, be proud of what you do. You’re making the world a safer place. Everyone else, think about all those things you buy. There was some process for making every one of them. Process safety played a really important role in products that you would never think of.

By | 2018-08-23T14:47:09+00:00 August 23rd, 2018|Chemicals, Combustible Dust, Process Safety|0 Comments

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