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Podcast: Lessons Learned From The Longford Gas Explosion That Killed Two

Sept. 30, 2020
A heat exchanger, management of change issues and a gap in knowledge led to a catastrophic incident. All of these were preventable mistakes. When will we learn?

This episode of Process Safety with Trish & Traci examines the Esso Longford gas explosion. Sadly, all the mistakes were nothing unheard of -- simply a chain of errors that caused the deaths of two workers. Here's what was learned. 


Traci: Welcome to this edition of "Process Safety with Trish & Traci," a podcast that aims to share insights from past incidents to help avoid future events. I'm Traci Purdum, senior digital editor with Chemical Processing. And as always, I'm joined by Trish Kerin, the director of the IChemE Safety Centre. Hey, Trish. How are you doing today?

Trish: I'm doing well. Thanks, Traci. We're starting into spring so the days are getting longer and the weather is getting finer. It's quite lovely. What about yourself?

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Traci: Well, we're the exact opposite. So it's getting darker earlier. And that always does a little something to your psyche. But I'm glad that you're going into springtime, but we're going to be entering into fall and winter here. So we'll take it when we can get it, right?

Trish: Absolutely. Fall is beautiful season as well.

Traci: It is. I wish it lasts longer.

Trish: Yeah. If you don't want winter.

Traci: Exactly. Well, today we're going to discuss an incident from what I understand is basically what launched your career into process safety, the Esso Longford gas explosion in Australia, which occurred on September 25th, 1998. So we're coming up on an anniversary for it. The explosion killed two workers and injured several others and gas supplies to the State of Victoria were severely affected for two weeks. What about this incident made you decide that you needed to be a part of the solution in terms of process safety?

Trish: At the time, I was working at a refinery that was connected via pipeline to one of the plants that was linked to Longford. So that's a long story, but Longford supplied an intermediate plant that then via pipelines shipped crude into the refinery that I was working at. And I was working in the part of the refinery that dealt with tankage and pipelines. So the offsides areas. And I remember getting...I was standing in the planner's office in the refinery when the phone rang, and he answered the phone. And he just sort of went a strange, pale shade of color when he answered the phone, and he got off the phone, and he said, "There's been an explosion at Longford and they're shutting down the pipeline."

So I said, "Okay, so we're going go into the process of shutting down the pipelines." And I was very process orientated and just get the job done. And he flicked the radio on at that point in time. And what got me the most at that point in time was I was standing there in the control room in the planner's office in a refinery and the news reports were telling us that there had been this explosion and that there were two people missing. And for me, at the time, it was the first realization of the magnitude of risk involved in some of the things that we do. Because we all looked at each other, we knew at this point in time they weren't missing. They were dead. There was no question about it in our minds. We had already figured that it was unsurvivable from what we've heard. And that really rocked me that day. And it's been something that stuck with me.


I mean, I could describe to you the precise moment of where I was and what I was doing when that phone call came through. It was one of those landmark moments for me. And what it was this could have been any of us, and I didn't want to be part of something where that happened. I wanted to be able to do something different. I'd previously dabbled in working in safety roles in the company so I had done some work in it. I had previously been involved into small process safety incidents that I hadn't really realized were process safety at the time until reflection many years later. This wasn't my first one that I was aware of that's for sure. And I went home from work that day thinking, "I've got to try and do something about this. If there's something I can do to stop the next one." And, you know, lofty goals for a young graduate engineer, quite frankly, because who am I to think that I could stop the next Longford quite frankly? But that was where my head was at the time. And it was the real shift that I made at that point.

The way I did things, the way I operated, the way I worked changed. And then I was then given the opportunity to move into safety in a more permanent role and I haven't looked back since and I have worked every day of my working career since to try and stop the next Longford. The challenge is you never know if you ever have. Sometimes it seems a little bit futile because you never know. If the incident didn't happen, then you never know that you helped it not to happen. But it's the best I can do to keep going because I have to believe that maybe some of the work that we do is helping keep someone safe so that they can go home at night and see their family.

Traci: Oh, a definite silver lining from such a tragedy to have you be such a champion for safety. And I know, reading the information on this, and the incident reports, the short answer for the cause of the failure came down to a heat exchanger. But can you go a little bit more into detail? What is the long tail of that story of what exactly happened?

Trish: Yes, so you really have to go back with most process safety incidents, years and years and years before the incident ever happened. There had been some plant changes that had been done and they had been risk assessed. But they hadn't been fully risk assessed in terms of truly understanding some of the interface differences. There were changes to the plant in the way the plant had to operate that hadn't really been taken into account. In addition to that, this was quite an old plant. It was built in the '60s, I think, from memory. It was the first gas plant at this facility, a definite one. And they had been a process where they were rolling out doing quite detailed HAZOPs because the plants were built before HAZOP ever existed as a process. So they were going through and retrospectively HAZOPing all of their plants. But the HAZOP of this plant had been put off for a while. And it kept getting put off for various different reasons. And it actually hadn't been done at the time the incident occurred.

So certainly in the investigation they had suggested that had a rigorous and systematic HAZOP being applied, possibly this causal event would have been identified and then potentially managed. But they had a situation where they had a gas plant operating. They had higher than normal flows because of the changes that have been made to the plant six weeks earlier. They had a situation where they had alarm flooding, a lot of alarms in the process system, a lot of alarms that would just be hanging around. They'd be silenced but you couldn't stop the alarm because the plant was permanently in an alarm state, so to speak, because of some of the changes and issues that they had.

Then they had a series of pump failures occur one day. And when those pump failures occurred, one part of the plant actually cooled down because they're dealing with gas condensate. There is very, very cold pieces of equipment, very cold systems, and the potential to build up ice in a gas plant. Now ice does build up in a gas plant because you do have cryogenic areas or almost cryogenic areas. The problem was that they had ice buildup in a part of the plant that was meant to be a lot hotter than it was. It was meant to be 240 degrees Celsius I think from memory, and it was about minus 42 degrees Celsius. We're talking a significant temperature difference here and it was a piece of carbon steel. It was a carbon steel heat exchanger. And that actually started to have a leak occur as well because the steel had contracted to such a point that the flanges were leaking. So the typical operations sort of idea of if you got a leaking flange, what do you do? Go and plug it up.

Well, they actually checked the tension. And the tension was right, but they couldn't plug it up. So they had to try and stop this leak somehow. And so from past experience, they knew that if you slightly heated up the equipment, the liquid go away. So they tried to do that. What they didn't realize at the time was that when you thermally shocked carbon steel from minus 42 to even ambient temperature with a hot oil flow, you will actually have a catastrophic failure because the steel has become so brittle. And so at that point in time, the heat exchanger ruptured, caused the explosion and fire and that tragically had the two operators lost their lives. Several others were injured. There was substantial damage to the plant. All sorts of different impacts occurred.

But the other thing that's interesting that underlies all this is a little bit before as well they had made a decision to relocate their process engineering department. This was a gas processing plant where they stabilized and condensate crude oil from the best rate rigs. And they had relocated all their process engineers to their Melbourne office which is about 200 miles away, I guess. And I'm sitting in an office in Melbourne but I didn't have full telemetry of the site. They didn't have the ability to monitor as we see process engineers. And we typically expect process engineers to be monitoring the flows, the operation of the plant, being able to talk to the operators in the control room. Those sorts of things. They didn't have full telemetry available to them.

Their relationship was only via phone effectively to talk to the operators and that created some problems because the engineers didn't really know that this was happening because they were so remote from it going on. And the operating people were found to have not understood the consequences of thermal shocking on cold steel environment issues. And so that's really some of the key issues that came out during the investigation into it.

Traci: Now, I know the investigation that was launched initially. Longford tried to blame the accident on worker negligence, but that really didn't fly. What was the final ruling?

Trish: The final ruling was that they were actually...there were two aspects to the investigation as such. The first one was that the regulator did prosecute. And Esso at that time were found guilty on all counts that they were charged with and they were penalized as a result of that financially. The regulator won the case in court to basically find the company itself guilty of this particular incident. The other thing that occurred, though, was there a lot of political concern and fallout over this particular incident. And so they established what in Australia and in some other countries they have them as well, we call a Royal Commission. A Royal Commission is the highest form of investigation you can do into any topic in Australia.

An eminent judge is appointed to lead it. They are given a series of counsel assisting, a series of investigators, as many experts, investigators that they need to do the work. And they have the powers of a court of law effectively in terms of compelling testimony and working through the facts. I guess it's our kind of version of the Chemical Safety Board. But we use Royal Commissions for all sorts of things. It's not just incident investigation. We have a Royal Commission into the finance sector, for example, and misconduct in the finance sector. We'll do Royal Commissions with all sorts of different things. But it's our way of getting to the bottom of what actually happened in something.

And the Royal Commission was ordered to take place, and it looked at the company, it looked at the incident, it looked at the regulator. It had findings against both the company and the regulator, not just the company. The regulator was actually found lacking in this incident as well. They hadn't been adequately regulating the facility. And so that was quite an interesting situation because it then led to recommendations that changed the way process safety is regulated in Victoria and that then permeated through the rest of the country as well. So that was the shift that we made towards the safety case type legislation. We got a new department in the regulator that focused on major hazards management. And an important part was they were required to create an oversight role of the regulator. There was a body established to keep an eye on the regulator to make sure the regulator was doing the right thing, which is a fascinating concept.

I actually sat on that body for about seven years later down the track in my career. The body was established from union representatives, company representatives, emergency services, and the community representatives. It was a group that drew together the people impacted from all angles. And we all work together to keep the regulator honest, basically. We would ask questions, we would challenge some of the assumptions or they wanted to get in certain parts, "No, we don't think you should do that. We'd like to see the regulator do this." But it was coming from a group that was combined of the community industry or companies and the unions, as well as emergency services. That was a really fascinating group to be part of. And I think it had, again, a lot of benefit in trying to really dig down and keep the regulator focused on what they needed to focus on. It was one part that came out of the Royal Commission.

The other part that came out was it was the opportunity to really deeply and analyze all of the incidents that led up to it, all the issues. So that's how we know that the plant hadn't been HAZOPed. We know that they had moved the staff. We knew that they were having trouble with that particular heat exchanger and the cooling down of it. We knew that they had experience of, "Well, if I heat it up, it stops leaking, so let's just heat it up." And so what was found then was that one of the issues, the moving of the operators or the engineers away from the facility created a gap in knowledge and understanding at the facility. And it's one of those challenges that when you're talking about competency, you can actually balance competency with effective supervision.

If you have a lower level of competency in a particular workgroup, if the supervisor has the knowledge, then with a little bit closer supervision, you can actually build those people's competency up and balance it out. If you've got a very competent group, your supervisor doesn't need to be technically competent. They still need to have knowledge, obviously, but they don't need to be as technically competent. Those things can balance out against each other. And what they actually found was that the operators didn't have the competency to understand this phenomenon of low temperature steel embrittlement. And the engineers who you would expect to have had that knowledge and competence weren't there. The supervision was lacking in that situation. I think that's one of the key elements that came out of it. There were various other management change related details and those sort of things. But that's sort of in a nutshell. It was around the lack of supervision, which was effectively why the operator negligence did not or was not accepted by the courts.

Traci: Because of that gap in knowledge, obviously.

Trish: Yes, yeah. They weren't deliberately doing anything wrong. They didn't have the knowledge to be doing what they were doing.

Traci: Now, aside from the tragedy that happened, the plant was the primary gas supplier in the area. What did that mean for Victoria's economy?

Trish: Well, it had a significant impact on Victoria's economy. But also more so Melbourne, the City of Melbourne. Melbourne is a the time, it was probably a city of about 2.5, 3 million people, I guess, thinking back that far. We're now at about 4 million, 4.5. We were smaller back then. But Melbourne was the second largest city in Australia. It's one of our major business hubs in the country it has been for a very, very long time. And all of a sudden, Melburnians woke up to no natural gas piped into their homes anymore. And because we live on the edge of best, right, where there's a lot of gas fields, pretty much everybody in Melbourne has gas hot water systems in their homes. A lot of people have gas heating as well and gas cooking.

The big issue that we had was all of a sudden, for a period of I think that lasted about 20 days, most people in Melbourne had cold showers. Now, that politically is unacceptable to the community. Because tragically, if you talk to anybody that lived in Melbourne at the time Longford happened they'll all tell you about cold showers. Sadly, they won't remember the names of the two men or even that two men died [There names were: Peter Wilson and John Lowery.]

. Yeah, I think that's a tragedy in itself, but they won't remember that detail. They won't know that detail. But they'll remember the cold showers and they'll tell you about the hardship of having cold showers. And so it was deeply politically frustrating for the ladies at the time. And that's why we had a Royal Commission. Royal Commissions back then weren't called very often. It's good to have a lot of them now but we didn't use that tool very much back then.

And the idea of a Royal Commission was quite significant. But not only did Melbourne's households not have any gas, Melbourne's businesses didn't have any gas. So commercial laundries that were laundering sheets and towels for hotels or hospital had no stain to do their commercial laundry. All sorts of different impacts started to occur because we didn't have gas. It was estimated in the end to have cost the Victorian economy about $1.3 billion at the time. It's Australian dollars. So I guess that's, what, about a billion U.S. There was a substantial amount of money back in the '90s. It's still a substantial amount of money, but it was worth a lot more then.

And there was this massive, massive impact. And that was aside from the cost of the damage to the plant and what needed to be done there. And that was aside from the cost of establishing an entirely new regulator, which obviously takes an investment to do. It certainly had a significant effect around industry, whether it'd be light industry or even heavy industry. So other major processing plants weren't able to operate because they didn't have gas supply to run their boilers or their incinerators or those sorts of things. Certainly there was all those sorts of flow-on impacts to it. At the refinery, we couldn't run out the crude that we wanted to run because you want to blend your crude to get your optimum output from your different products.

And the Gippsland oil was actually one of the key feedstocks to the refinery. And in fact, one entire crude unit was built and designed to run on Gippsland oil. Not only other oil, Gippsland oil. And so it had a significant flow to effect that then affected the ability of the refineries to produce gasoline and diesel. You couldn't just back it up with, "Well, the refinery can make us some LPG and we can get buy on it and we can get some diesel and petrol." Well, no, because the refiners couldn't run the normal rates they were running because all of a sudden they didn't have the crude feed they needed to run. So it had all those sorts of different follow-on effects that occurred as a result of it. It is amazing today that you can still talk to someone about, "Do you remember when Longford happened and we had a cold shower? It was horrible."

It's burned into our memories, this idea of cold showers in that September into October. Lucky, it was spring but it was still quite an impact. Personally, at the time, the place where I lived, we actually didn't have gas. My life in terms of at home went on completely unaffected because I lived in a very old property that had no gas pipe to it. So I had an electric hot water system, I had electric cooking, had no issues at all. Everybody I worked with was showering at work because that's where the hot water because the refinery still was able to heat its water. So all sorts of different impacts and things you remember. But to this day, that incident has stuck with me. And as we said at the start it was a turning point for me. And it's one of the key things that drives me every day to do what we do in the Safety Centre.

Traci: And that brings me up to a question of how can the learnings from this incident mitigate future process safety issues? We've touched on a few of them but what a good walk away is from this?

Trish: Well, I think the big challenge we've got is we actually have to learn. We have to stop repeating the same incident mechanism over and over and over again. At the time, low temperature steel embrittlement was not an unknown phenomenon. It was known. Why hadn't we learned? We need to do much better risk assessment activities. We need to really make sure that when we do a risk assessment it is robust and it gets to the very heart of what the hazards are, what the consequences are, and what we can do about them. We need to make sure that we adequately train our workforce. They not only can do their job, but they understand when it's not going right. They can recognize that potentially something's different, something's wrong and I need to stop and we need to assess and we need to engage with other people to understand what's going on.

So unfortunately, there's no new learnings in this incident. And you get your risk assessments right and your hazard assessment done. Get your competency right and make sure your people know what they're doing. Make sure that you don't end up in a situation of alarms like when this thing happened. They had so many alarms coming through at them in the control room. They had no hope of doing anything. And keep in mind, the control room was severely damaged in the explosion as well. So a lot of the injured were in the control room and they were trying to then figure out what was going on and deal with it. I think they're probably the key takeaways. But sadly, there's nothing new in that. You know, you make sure you're competent. Understand your hazards and implement controls. There's nothing new in any of that. But that's sadly what we tend to lack being able to do on a rigorous and repeatable basis. And until we can get to that point that we do that day in, day out, we will continue to see incidents occur. We've not yet seen a new phenomena for a very, very long time. But we've seen the old ones repeated again and again.

Traci: And it's the question of how do you solve complacency? And that's the $64,000 question. I think that's what happens is that just the complacency and it's not going to happen here. And we've said before and you've said before, those are the dangerous words in the English language that it won't happen here. Is there anything you want to add to this conversation that we didn't touch on already?

Trish: I think, I guess, for me, be curious is a really important way to approach your work. Be curious about what's going on around you and about what might happen next. Because that will help you start to look for things. We can so often fall into the trap of just going along and doing the job. We just get there. We just do the job. That, "I'm just here to do the job and I'm going home." But sadly, if we don't have that curiosity to force us to look for things, we might not go home. And so that's I think the point I'd like to leave everybody with today. We have the power to change this, we have the power to fix this. But we actually have to have the curiosity and the will to go through with it.

Traci: And the curiosity from those that may not have the extreme knowledge that their higher up have. So asking the questions might spur safer processes.

Trish: Absolutely. Absolutely. Ask questions. If you don't know something, ask the question. What's the worst that could happen? You might feel that you might look silly, but in fact, you probably won't. Because if you're having that question in your head, chances are someone else is too. And you might actually trigger a conversation to occur that might prevent an incident and save someone's life. It's that simple. Never be afraid to admit you don't know something. The worst thing you can do is pretend that you do know it and just not do anything about it. But never be afraid to admit you don't know something and seek out the question. That's a very noble way to conduct your work

Traci: Well, great advice there. I'm happy that you're out there fighting for Process Safety and making sure folks can go home. And you're right, you don't know if the work you're doing is working because if there's no incidents. But if there's no incidents, it is working. Unfortunate events happen all over the world and we will be here to discuss and learn from them. On behalf of Trish, I'm Traci and this is "Process Safety with Trish & Traci."

Trish: Stay safe.

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Trish Kerin, director, IChemE Safety Centre, Institution of Chemical Engineers, spent several years working in design, project management, operational, safety and executive roles for the oil, gas and chemical industries. She currently sits on the board of the Australian National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) and is a member of the Mary Kay O'Connor Process Safety Center steering committee. You can email her at [email protected].
Traci Purdum, an award-winning business journalist with extensive experience covering manufacturing and management issues, joined Chemical Processing as senior digital editor in 2008. Traci is a graduate of the Kent State University School of Journalism and Mass Communication, Kent, Ohio, and an alumnus of the Wharton Seminar for Business Journalists, Wharton School of Business, University of Pennsylvania, Philadelphia. You can email her at [email protected].

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