Henry David Thoreau of Process Safety: Trevor Kletz

Traci Purdum: Process Safety with Trish and Traci is a production of Chemical Processing. Chemical Processing focuses on serving engineers designing and operating plants in the chemical industry. Welcome to Process Safety with Trish and Traci, the award-winning podcast that aims to share insights from past incidents to help avoid future events. Please subscribe to this free podcast on your favorite platform so you can continue learning with Trish and me in this series. I’m Traci Purdum, editor-in-chief of Chemical Processing, and joining me as always is Trish Kerin, director of Lead Like Kerin. Hey Trish, what has inspired you this week?

Trish Kerin: Well, I actually did some volunteering yesterday with an organisation that I’m working with and spent about half a day packing food for people that have food insecurity. So it was a really affirming activity to do, and certainly highlighted how much privilege I have in my life. You know, it made me feel quite humble about that, but it was a wonderful experience, great team building with the team I was working with.

Traci Purdum: It’s always good to give back, for sure.

Trish Kerin: Yeah, and congratulations are in order for you, winning an Eddie Award.

Traci Purdum: Oh, thank you.

Trish Kerin: For one of your articles. So fantastic. So, you know, multi, multi award winner you are.

Traci Purdum: And always nice to get accolades. It was the column I wrote for Earth Day. It was called Lax Regulations Burn River. So I was pretty pleased with that, because I got to weave in a little bit of my hometown lore in there, Cleveland, Ohio, and then just talk a little bit about regulations and what’s been happening in the recent news. So I was proud of it.

Trish Kerin: Eh, good, good.

Traci Purdum: Well, speaking of inspiration, today’s episode is dedicated to Trevor Kletz, who sparked a whole process safety movement. Trevor was a pioneering British chemical engineer who revolutionized process safety in the chemical industry. His influential writings, including over 20 books and numerous papers and even articles in Chemical Processing, introduced concepts like HAZOP studies and promoted a culture of safety through shared knowledge. His work fundamentally transformed how industries approach risk management, making chemical plants worldwide significantly safer through his practical, experience-based approach. First question for you. Did you ever meet Trevor?

Trish Kerin: Sadly, no, I didn’t. I didn’t ever have the opportunity before I started to work for IChemE, and I’d only been at IChemE about a year or so, a year and a half, when Trevor passed. And so sadly, I did not ever get a chance to meet him, though I did meet his son, after IChemE named their plenary lecture in their Hazards conference after Trevor, and his son came to that first Trevor Kletz Memorial Lecture that we held.

Traci Purdum: I didn’t realize his son was involved in that as well, so that must have been interesting.

Trish Kerin: Yeah, it was. It’s, you know, as we are with most of our parents, we probably don’t always realize how much they actually did in their work life, because we see them as our parents. And so I think it was probably quite surprising for his son to actually realize the influence that his father had had, because we generally don’t connect that with our parents. They are parents, right? They’re not other people that have other lives and do other things. But certainly they do.

Traci Purdum: And he had quite a life, for sure. Let’s talk a little bit, and you and I were chatting before we got online here, about HAZOP. What made his approach to HAZOP studies revolutionary, and how did it change the way industries identify potential hazards?

Trish Kerin: Yeah, so sometimes people actually make the assumption that it was Trevor that did actually develop HAZOP. And in fact, in his own words, he says that he didn’t. It was developed by another engineer called Ken Gee at ICI, and he decided to apply a detailed critical examination technique, as he called it at the time, that they applied to management decisions, and he decided to apply it to a plant design. And he spent, in the design of a new plant, something like three days a week, every week, for four months, studying the design of this plant. And Trevor at the time didn’t get involved in that particular activity, because he was busy being a plant manager and was far too busy for that sort of activity to take place. But then he actually said, later, when I took the full-time safety job, I became an enthusiastic advocate for HAZOP.

And I think the key part about HAZOP is that it is such a structured methodology that it forces you to consider all sorts of different activities or conditions that, if you were just brainstorming, you would not necessarily consider. In fact, you might even discount and say, I know that just can’t happen. And so by virtue of doing the HAZOP, it actually forces you to examine every line by line in the design and say, okay, what happens if there’s no flow, too much flow, zero flow, whatever it is. You go through a series of guide words and you focus on every permutation that can exist.

And it’s now been expanded to so many different applications as well. So we have CHAZOP, which is a control system HAZOP. We do procedural HAZOP now. There’s a whole range of different HAZOPs that we do that really, I think thanks to Trevor’s enthusiastic advocacy of HAZOP, we end up with this broad application of a tool that was developed in the 1960s. And the core of it actually hasn’t really changed, which says that it was a pretty good tool to start with if, you know, all these years later we’re still using it and it is still delivering us great safety discovery and understanding of our designs. And so Trevor’s advocacy of it, his use of it, his promotion of it, I think has been fantastic for industries all over the world that use that tool now. And his enthusiastic advocacy of everything process safety.

Traci Purdum: Really, you know, he really kind of was revolutionary in being able to see the forest through the trees and understand what really mattered. And that’s always something that, you know, every day I learn more about Trevor Kletz. Let’s talk about inherent safety. Can you explain his concept and give some examples of how it differs from traditional add-on safety measures?

Trish Kerin: There’s many, many quotes of Trevor’s over the years, and when you’re working in process safety you almost can’t go by a single day, or at least a week, without at some point in time a Trevor Kletz quote popping up somewhere. And one of his famous quotes was, what you don’t have can’t leak. So think about that for a moment. What you don’t have can’t leak. And that is the fundamental basis of inherently safer design principles. It is all about how do we deal with that hazard in such a way in the design that we don’t create the potential risk.

There’s a range of different steps or elements that we can have in inherently safer design. So the first one is eliminate. Can we eliminate the hazard? What you don’t have can’t leak. If you don’t have it, it can’t cause you a problem. So this is around going right back to the concept design and saying, well, can we actually take the hazard away? If we can take the hazard away, then we don’t have to manage it. And that’s the real difference between the add-on safety measures and inherently safer design. If we can deal with the hazard in its design, then we don’t have to manage it, because it doesn’t have the same impact.

So the first one’s eliminate. The next one is minimization, or intensification. So this is, where can we minimize the amount of the hazard that we have? Again, what you don’t have can’t leak. If we only have 100 litres and not 1,000 litres, we can only spill 100 litres. This one is around how can we minimise the amount of the hazard that we’re using, and we may do that through the concept of process intensification. So we may look at increasing pressure or temperature in one way, but it reduces the need for something in another way. So we do trade-offs in inherently safer design. There’s no one thing that’s absolutely safe. We actually have to make some trade-offs in that.

We also then talk about substitute. Can we take that hazard and substitute it for something less hazardous? That’s another option. So again, it all comes back to what you don’t have can’t leak. Moderate, or reducing the severity of the hazard. So can we actually change the design parameters? Can we change the way we’re doing it so that we actually reduce the severity of the hazard that we have? And all of these are fundamentally built into the design. They’re not add-ons. Once we start adding on, we’re actually beyond the realm of inherently safer. It’s in the title, inherent. It has to be built into the design.

And the last one that is sometimes forgotten, and we’ll get to it a little bit later in our discussion, because you can’t have a discussion about process safety and Trevor Kletz without talking about simplification. How do we actually simplify the plant? Make it as easy as possible to use, so that people don’t make a mistake, because we’ve removed the potential of the mistake, is what we want to try and do. We’ve removed the ability for the mistake to occur, or for the mistake to drive a significant risk outcome. And so that’s what we tend to focus on, and all of those elements, as I said, they’re things that we actually build in to the design. So we’re not adding on alarms and shutdown systems and all these sorts of things. They’re not inherently safer. They are add-ons. They’re not part of the actual management of the hazard intrinsic to itself. And so that’s the real difference there.

Traci Purdum: Talking about building in the design, there’s a factor there. It’s the human factor that you don’t have in that design. And let’s talk a little bit about how Trevor transformed the way industries view human error, from blaming operators to examining system design.

Trish Kerin: This podcast is going to be full of Trevor Kletz quotes, isn’t it? That’s all right. The next one I’d like to share with you is this one. Saying an accident is due to human failing is about as helpful as saying a fall is due to gravity. It is true, but it does not lead to constructive action. Instead, it merely tempts us to tell someone to be more careful.

And when you think about it, yes, we are humans. We all make mistakes. We make mistakes every day. I lost my mobile phone this morning, my cell phone. I had to hunt around the house finding it. I made a mistake. I put it somewhere and forgot where I put it, because it was an unusual place. That was my mistake. We all make mistakes every day. When the outcome of those mistakes can lead to a significant process safety event, that’s a problem. That says our system is not designed well enough. Our system is not resilient, and we are in a situation where we are at risk of something going wrong when we need a human to get it right 100% of the time, because sadly we never will.

And so he really changed this focus and said it’s actually not about the human making mistakes, they’re going to make mistakes. What we need to do is engineer our systems to be resilient enough that the mistake doesn’t matter. So this is about really focusing on how can we design our systems in such a way that they’re more inherently safer, so that when someone does make the inevitable mistake, it doesn’t cause the incident. It might be a minor plant upset, it might be inconvenience of some sort, but it’s not actually going to cause a catastrophic outcome, and that’s what this is all about. So it’s really about coming back and accepting that humans make mistakes.

And it was actually an adaptation of the human factors field of study, which was actually first really developed in the 1930s in the aviation sector. So aviation, rail and now healthcare have been doing human factors for a very, very long time. Processing industries have been doing it now as well for quite some time. I still think we’re a little bit behind some of the other industries, but as I said, aviation’s been doing human factors since the 1930s, 1940s. They’ve got a bit of a head start, but I think we can do more in the process industries to really get beyond this idea that the human made a mistake, therefore we punish the human. That is not going to solve the problem. And as Trevor said, it merely tempts us to tell someone to be more careful, and that never solved a problem.

Traci Purdum: No, it didn’t. What are some of the most important lessons from his case studies, and why did he believe learning from accidents was so crucial? That’s something that you and I talk about all the time, and it stems from his experiences.

Trish Kerin: Yeah, it’s really down to, we need to learn from what has happened before, because if we don’t, it’s going to happen again. And this is where I’m going to now bring in another two Trevor quotes. The first one is that organisations have no memory, only people have memory. And so this is one of the challenges that we have in learning. People remember something they’ve been involved in, something they’ve experienced, and it’s had a deep impact on them. When they leave an organisation, the learning, that experience, goes with them. And so that’s one of the challenges we have: how do we take this valuable learning that people have, and how do we embed it into the next generation in the organisation? Because we can have knowledge management systems, and it’s all refined to have a lot of data and a lot of information, a lot of knowledge available to people. If they’re not looking for it, then it’s just the digital equivalent of a dusty book on a shelf.

So how do we actually take these valuable lessons that we have and embed them in the next generation, and the next generation, and the next generation? Because it’s not a knowledge management system that actually makes decisions. It’s our humans that make decisions. So we need them to have this background, to have this information. And that is why learning from case studies is so important, because it takes what might just be a theoretical idea to someone, and it actually explains it in such a way that we see how it could eventuate, because we talk about an example of when it did eventuate. And I think that’s a really critical part.

So, you know, one of Trevor’s books that he actually wrote was called What Went Wrong, and then he wrote another one called Still Going Wrong, and he tells all of these case study stories. He also then talks about incidents that will happen today and tomorrow, and he actually predicts them in some of his books. And you sort of say, well, how could he possibly predict them? Well, because they’ve already happened somewhere else before, and we are still repeating them over and over and over again.

And I remember as a young engineer, one of the ones that stuck with me the most was, he actually talked about the number of atmospheric storage tanks that will be sucked in every year, because it doesn’t take much to suck in an atmospheric storage tank. And you look at these big steel tanks and you think, how is that possible, that a simple plastic bag taped over a vent, because we were painting the outside of the tank, for example, and we forgot to remove the plastic bag, how is it that that can cause a tank to be completely sucked in on itself? Because logically, that just doesn’t make any sense. So you actually sit down and do the calculation. And the calculation for what vacuum pressure an atmospheric storage tank is designed to is not that great a number. It’s quite a small differential number. And Trevor in his book actually goes through and compares it to a cup of tea or a cup of coffee, because it’s only a couple of inches of water pressure that is enough to suck in an atmospheric storage tank.

And so he had this amazing ability to take a complex topic and simplify it in a way that more people could understand the message. He was never simplistic, and that’s a really important thing. It’s not about being simplistic, and I hate the term when people say it, dumbing it down. No, it’s not dumbing it down. What it’s doing is it’s just giving you a simile or a metaphor, something you can relate to, to understand it. And so I look at my cup of coffee and think, gee, it’s only that amount of pressure that it takes to suck in a storage tank. That is pretty intense when you think about it. So he created his stories in his case studies in this sort of way, so that you could relate to what was there, and you could actually then start to apply it and remember it. And so yeah, you know, I sat down as a young engineer and went, I’m going to do that calculation myself. And he was right. What a surprise. Trevor was right, and you know, I had to go prove it mathematically. I was a young engineer. But, you know, these are really, really important lessons, and that one stuck with me for decades, because it’s just so incredulous, yet it’s true.

And I said I was going to give you another quote, didn’t I, actually? The other quote I was going to give you, which is also one that I love, because it does also come into this learning and this case study, of when someone says, oh well, you know, but that’s so unlikely, it’s just too expensive to fix. And his next quote is, if you think safety is expensive, try an accident. And that’s a really important one as well, that sometimes we might have to invest in safety, but what we’re investing to prevent a loss of is much, much greater. So you might invest $50,000, but the incident you’re preventing might be $10 million. You know, $50,000 doesn’t sound a lot when you think about $10 million, but we do get lulled into this false sense of, oh, but we won’t have that $10 million loss. We’ll be okay. We can ignore the $50,000. And you and I have spoken before, and you know that I often talk about, when we are investing in process safety, we’re actually investing in reliability. And reliability gives us productivity, and productivity can let us make money. So process safety, it can be expensive, but it can also make you money.

Traci Purdum: And as you point out, the simple message is the one that sticks with you, and I think you are very talented at that as well, and maybe it’s because of the cup of coffee and going on from that, and because it’s stuck with you that you help us with the similar story. So I appreciate that. Let’s talk a little bit about what Trevor meant by a friendly plant, and how can that philosophy be applied to modern industrial design?

Trish Kerin: Yes, so the friendly plant concept was really coming back to one of those inherently safer design elements I talked about, which is simplify. If we make the process as simple as possible, then there’s less steps for it to go wrong, less opportunity for a human error to cause something that could lead to a catastrophic event that we’re trying to avoid. So really this whole idea of the friendly plant is, how can we take a really critical look at our designs, and does it need to be that complex? Does it need to have that many intermediate steps?

And one of the incidents we often talk about in process safety is Bhopal. Now, Bhopal had their methyl isocyanate stored in tanks, but it was only an intermediate product. And so you would say that that perhaps wasn’t a friendly plant from Trevor’s idea there. They didn’t need to manufacture their MIC and keep it in storage and then use it at a later date. They could have actually run continuous operation and consumed it as it was produced. Because remember, what you don’t have can’t leak.

And so taking a look at these things, do we actually need that intermediate storage, or can we actually produce and consume? Can we change the formula and the process of how we’re producing to eliminate steps altogether? And so sometimes it comes back to looking at the base chemistry of, you know, can we actually formulate this in a different way? Sometimes it comes back to looking at, you know, how do we go through some of the other elements of inherently safer design? So if we need a solvent as part of our process, does it have to be a flammable solvent, or can it be an inert solvent, potentially? We look at these different elements that we can put in place.

So one of the things that we can think about doing, in how we apply this to modern industrial design, is to say, do we need to have all of the complexity? Just because we can doesn’t mean we should, in some ways. So when we talk about all this amazing technology we have, automated shutdowns, alarm systems, all these things, they’re not inherently safer. They’re the add-ons afterwards. And we can, as engineers, get quite excited about adding on more and more and more controls, but that’s not necessarily making us any safer. Sometimes we actually need to strip back and say, okay, let’s go back and deal with the core hazard inherently, so we don’t need to just keep adding on all of these additional bells and whistles, or belts and braces. We don’t need those things. We need to actually deal with our hazard at its core. And then there will be some of these add-ons we put in, without doubt. We need some of them. But sometimes in our modern plant designs we get far too focused on all of these different aspects, all of these different technologies. And as I said, just because we can put a technology into place doesn’t necessarily mean we should. Think about it from that simplification and that friendly plant perspective.

Traci Purdum: And he was very critical of overly complex safety systems and offering all of the alternatives. Were there other alternatives that come to mind?

Trish Kerin: So yeah, he very much brought everything back to, let’s manage that hazard. Remember, it all came back to what you don’t have can’t leak. And as engineers, that means we need to sometimes get a little bit more creative. As chemists that are designing processes, that are designing formulations, how can we apply what we now call the concepts of green chemistry? So green chemistry is very, very similar to the whole idea of inherently safer design, but it’s all around the formulation. So focusing on how we can actually go through that process and try and manage what we’re doing in a different way, in a different way to deal with that hazard. And so simplification, removing the hazard wherever we can, and if we can’t remove it, then how do we go for a less hazardous alternative in some way, is really what he was a significant advocate on. And I think our designs are better for his input over the many, many decades that he contributed to process safety as we know it today.

Traci Purdum: He truly was the Henry David Thoreau of process safety, with simplify, simplify, simplify.

Trish Kerin: Yes.

Traci Purdum: Trish, is there anything you want to add about Trevor?

Trish Kerin: If you’ve never heard of Trevor Kletz, or if you’ve never read any of his books, go and get them. Go and find any of Trevor’s books and just have a read. He was a prolific author. He wrote many, many, many books. As I said, What Went Wrong, Still Going Wrong. There’s so many out there. You will learn so much. They are easy to read. They are not deeply complex. He takes the complexity of incidents and explains them in a beautiful way that we can understand. And so go get yourself some Trevor Kletz books and read them, as a process safety engineer, or indeed as a leader or manager in a field that deals with process safety hazards. You will learn so much. It will make you a better person in your role. So please go and read his books.

Traci Purdum: Well Trish, you obviously learned a lot from Trevor, and you help us with that. You help us embed the valuable lessons that we go through every day, learning of all of these catastrophic events. Unfortunate events happen all over the world, and we will be here to discuss and learn from them. Subscribe to this free award-winning podcast so you can stay on top of best practices. You can also visit us at ChemicalProcessing.com for more tools and resources aimed at helping you run efficient and safe facilities. On behalf of Trish, I’m Traci, and this is Process Safety with Trish and Traci. Thanks, Trish!

Trish Kerin: Stay safe!

Traci Purdum: This episode of Process Safety with Trish and Traci was produced by Endeavor Business Media, a division of Endeavor B2B.