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How Deep is Deep? The 20 Deepest Tech Shipwreck Dives and How They Compare to Dives in the 1990s



By Michael Menduno

*This article has been updated from this version to the 30 Deepest Shipwrecks and new wrecks have been added after reader feedback.

The advent of mixed gas usage by sport divers—the so-called “Technical Diving Revolution”—in the early to mid-1990s greatly expanded our community’s underwater envelope, while arguably improving diving safety. In order to appreciate how far, err deep, we have collectively come, I thought it would be illustrative to contrast the deepest tech shipwreck dives from today to those in the 1990s when technical diving was just getting started. A similar exercise could be done with cave diving.

Back in the early to mid-90s, technical diving pioneer Capt. Billy Deans, owner of Key West Diver, observed that mix technology enabled us to “double our underwater playground.” Deans was contrasting the then existing recreational diving limits, (i.e., no-stop dives to 130ft/40m) to the new technical diving envelope that was made possible with the use of helium-based bottom gas and accelerated decompression using nitrox and oxygen. Note that during this period, the words “deep” (beyond 40 m) and “decompression”, (i.e., “The D-words,”) were considered four-letter words by many in the recreational diving establishment.

At the time, we considered open water decompression dives with 15-25 minutes of bottom time to depths of 260 ft/79 m to represent a reasonably reliable envelope for technical mixed gas diving operations. That’s what Deans meant about doubling of our recreational playground. Because of the ability to more easily stage bailout and decompression gas in the cave environment, the envelope there was considered deeper/longer. That is not to say that tekkies weren’t diving deeper than 260 ft/79 m and staying longer, but at that time, we considered these dives to be “exceptional exposures”, requiring special methods and work.

Deep Shipwreck Dives in The 1990s

Table 1 below highlights the ten deepest tech wreck dives from 1989-1999, including their location, depth, dive profile, the technology used, and the technical divers who first dived the wreck. The majority of these dives were reported at the time in my magazine aquaCORPS Journal. The deepest dive at the time was the Edmund Fitzgerald at 530 ft/162 m in Lake Superior. The shallowest in the table was the RMS Lusitania at 310 ft/95 m.

Average depth: 398 fsw/122 msw, Avg Bottom Time: 16.7 min Average Run Time: 192 min  

* Note that Tysall & Zee’s dive on the Fitz was essentially a “sneak” dive i.e. they did not have permission to dive the wreck, which was a gravesite, though they laid a plaque on the wreck with the names of the fallen.

** Denlay & Tysall’s first dive in 1995 was to 361 fsw/110msw on the shallow stern of the Atlanta. They returned in 1997/98 where they made their deepest dive to the bow.

** Jacque Cousteau, Albert Falco (team leader), Raymond Coll (camera), Ivan Giacoletto (lights) and Robert Pollio (photo), were the first to dive the Britannic in 1976. Their first recon dive was on air!! Subsequent dives with BT: 15 min were made with Trimix 14/54. The team deco’d in a bell. GUE launched its own expedition in 1999 which included the Lundgren brothers. 

There are several observations to be made. First, all of these dives were conducted on open circuit. At the time, literally, only a handful of tekkies had rebreathers, which were either modified Carleton Mk 15.5s, Dr. Bill Stone’s handmade Cis-Lunar rebreathers, the Halcyon PVR-BASC semi-closed rebreather aka “The Fridge,” the predecessor of the RB80, or various prototypes. AP Diving’s “Inspiration,” the first full-production sport rebreather, would not be released until mid-1997. As a result, rebreather use would not hit its stride for another decade.

Jarrod Jablonski, Dr. Todd Kincaid, and Richard Lundgren planning their dive on the HMS Britannic in 1999.

Two of the dives shown in the table, the Frankfurt (420 ft/129 m) and the Ostfriesland (380 ft/117 m) were conducted by wreck diving pioneers Ken Clayton and Gary Gentile on heliox (an oxygen-helium mix). In 1989, Clayton, Gentile and their team also conducted deep air dives with air decompression—can you imagine??—on the USS Washington (290 fsw/89 msw), which represented the 11th deepest shipwreck dive and did not make the list. Ironically,  even though cave divers quickly embraced “special mix” technology, the majority of serious Northeast U.S. wreck divers were slow to adopt mix technology to replace their deep air diving. However, they did begin using oxygen and or nitrox for decompression.

In terms of divers, Terrence Tysall, now the training director for National Association of Underwater Instructors (NAUI), made the two deepest dives in the 1990s table; the first was while diving the Edmund Fitzgerald with Mike “Zee” Zlatopolsky, the second on the USS Atlanta with Aussie tech pioneer Kevin Denlay. Clayton, Gentile and their teammates accounted for four of the ten deepest wrecks while Gentile was involved with five of the ten, and Deans and his team accounted for two dives on the list.

Note that at the time,  British tekkie Polly Tapson, one of the first female tech expedition leaders, and her team “Starfish Enterprise” captured the imagination of the community with both their preparations and successful dives on the Lusitania in 1994.

Three years later, British tech pioneer and inventor Kevin Gurr launched the first technical expedition on the Britannic with Dave Thompson, founder of JJ-CCR, Al Wright; Global Underwater Explorers’ (GUE) Richard Lundgren; his brother, photographer Ingemar Lundgren; photographer Dan Burton; and British tekkie John Thornton. Of course, the wreck was first discovered and dived by Jacques Cousteau and his team in 1976 (see Table 2).

GUE launched its own Britannic expedition in 1997 with a large team consisting of Jarrod Jablonski, Todd Kincaid, Richard Lundgren, Panos Alexakos, Per Andersson, Johan Berggren, Steve Berman, Ted Cole, Andrew Georgitsis, Joakim Johansson, Sigmund Lundgren, Barry Miller, Tyler Moon, Mikael Ollevik, Anthony Rue, and Bob Sherwood.

In terms of dive exposure, the average depth of these 1990s wrecks was 398 fsw/122 msw, the average bottom time was 16.7 minutes, and the average run time was 192 minutes or slightly more than three hours.

The Deepest Shipwreck Dives Today

Table 2 shows the 20 deepest technical shipwreck dives as of 2018, again identifying the first tech teams to dive on the wrecks. Note that only the five deepest shipwreck dives from the 1990s made it on the new list. The deepest was the mv Jolanda, dived in 2005 by Leigh Cunningham and Mark Andrews to a depth of 669 ft/205 m.

This Table has been updated to reflect new information. View the new table here. 

Average depth: 588 fsw/179 msw Avg. Bottom Time: 19.3 min Avg. Run Time: 366 min 

* The wreck sits vertically from 70-150 msw.

** Scuttled in Operation Daylight, Operation Deadlight Type VII 

***Denlay & Tysall’s first dive in 1995 was to 361 fsw/110msw on the shallow stern of the Atlanta. They returned in 1997/98 where they made their deepest dive to the bow.
A GUE team returned to film a documentary “USS Atlanta, Defender of Guadalcanal” in 2011 and conducted 40-min bottom times with up to 360 min runtimes using RB80s and trimix 8/90. Team: Richard Lundgren, Jarrod Jablonski, Casey Mckinley, Liam Allen, Kirill Egorov and JP Bresser

**** The wreck had been dived previously in September 2000 by Richie Stevenson, Chris Hutchison and Dave Greig but only as a bounce w/ 2 min bottom time.

***** Jacque Cousteau, Albert Falco (team leader), Raymond Coll (camera), Ivan Giacoletto (lights) and Robert Pollio (photo), were the first to dive the Britannic in 1976. Their first recon dive was on air!!  Subsequent dives with BT: 15 min were made with Trimix 14/54. The team deco’d in a bell. GUE launched its own expedition in 1999 which included the Lundgren brothers.

 Viewed from today, the 20th deepest wreck dive is the HMHS Britannic at 395 ft/120m, slightly shallower than the average 400 ft/123 m depth of the 1990s list. The deepest dive in the 90s, being the Edmund Fitzgerald, aka ‘The Fitz” is now #8 when viewed from today. That is to say that nine of the ten deepest shipwreck dives today were conducted after 2000.

Note also that there is one high altitude shipwreck dive on the list: the SS Tahoe, which was first dived by Martin McClellan and Brian Morris at a depth of 471 ft/144 m, and lies in Lake Tahoe at an altitude of 6,224 ft/1,897m. The altitude makes the SS Tahoe a no-man’s land in terms of decompression knowledge; there is almost no data to validate procedures for aggressive dives at that altitude. Only Sheck Exley and Nuno Gomes’ series of sub-500ffw/153mfw open-circuit cave dives from 1992-1996 at Boesmansgat sinkhole, which lies at an altitude of 5,000 ft/1,500m in South Africa, were possibly more extreme.

HMS Curacoa Bridge –  Diver: Stewart Andrews, Photo by Barry McGill.

Twelve of the current deepest shipwreck dives (all five from the 1990s) were conducted on open-circuit while the remainder were conducted with closed-circuit technology. All the dives but one were made using trimix as a back gas or diluent, the exception being the Frankfurt first dived by Clayton and Gentile and their team on heliox as discussed above.

The average depth of the ten deepest shipwreck dives viewed from today is 588ft/179m, a full 188ft/57m deeper than the ten deepest shipwreck dives from the 1990s.

Closed circuit technology is partly responsible for the deeper depths and longer dives we see today. The average depth of the ten deepest shipwreck dives viewed from today is 588ft/179m, a full 199ft/61m deeper than the ten deepest shipwreck dives from the 1990s. Average bottom time for the deepest ten was slightly longer at about 19.1 minutes compared to 16.7 minutes for the 1990s wrecks; however, average run time was 366 minutes and a little over six hours or nearly double, the three hour run times in the 1990s due to the increased decompression obligations.

Irish tekkie and photographer Barry McGill, his colleague Stewie Andrews, and their various teams were responsible for three of the 25 deepest shipwreck explorations. Aussie tekkies Dave Bardi, Craig Challen, Richard “Harry” Harris, and their colleagues from the “Wet Mules,” who were prominent in the Thai cave rescue earlier this year were responsible for two of the deepest wrecks. They also dived on the HMS Victoria three years after Mark Ellyat and Christian Francis. Samir Alhafith and his teams also accounted for two, as did Jeff Cornish, Mark Dixon and their teams. Tysall remained on the list for his dives on the Fitz and the Atlanta.

Note that in 2011 a GUE team consisting of Richard Lundgren, Jarrod Jablonski, Casey McKinley, Liam Allen, Kirill Egorov, and JP Bresser, returned to the USS Atlanta to film a documentary “Return to the USS Atlanta, Defender of Guadalcanal” and conducted 40-minute bottom times using RB80s, with up to six-hour run times using trimix 8/90 as back gas.

Image of the USS Atlanta from the Global Underwater Explorers expedition in 2011. Image Credit: TBD. 

Have we reached our depth/time capability as self-contained divers? If history is any judge, likely not. My long-held belief is that self-contained atmospheric diving systems (ADS) aka Exosuits or hard suits such as those developed by commercial pioneer Phil Nuytten, founder and CEO of Nuytco Research, represent the next wave of technology that promises to extend our envelope even further. However, given the slow pace at which diving technology evolves (it’s a matter of economics), it may be awhile before divers will have access to a $10-$15,000 swimmable Exosuit. Even so, it will be interesting to see what the list of the 10 deepest tech shipwreck dives will look like in 2038. No doubt GUE and others will be there.

Note, I researched these charts over the last two years, but there is missing information in addition to possible errors or omissions. If you find any, please notify me at m2@GUE.com and we will correct them.

Top Image: HMS Curacao deck gun near the break where the Queen Mary struck. In the background – Diver: Stewart Andrews. Photo Credit:  Barry McGill.

Michael Menduno is InDepth’s executive editor and, an award-winning reporter and technologist who has written about diving and diving technology for 30 years. He coined the term “technical diving.” His magazine “aquaCORPS: The Journal for Technical Diving”(1990-1996), helped usher tech diving into mainstream sports diving. He also produced the first Tek, EUROTek, and ASIATek conferences, and organized Rebreather Forums 1.0 and 2.0. Michael received the OZTEK Media Excellence Award in 2011, the EUROTek Lifetime Achievement Award in 2012 and the TEKDive USA Media Award in 2018.


The Role of Agency When Discussing Diving Incidents: An Adverse Event Occurs—An Instructor Makes a Mistake

Human Factors educator and coach Gareth Lock examines the role of our innate attribution biases and language, in forming our collective judgements when incidents occur—in this case, by considering a student diving injury that occurred during a class. Was the instructor to blame? Was anyone?




by Gareth Lock

Header Photo by Alexandra Graziano

What do you think when you read the following? Who is at fault? Where do you think the failures lie?

“The instructor failed to notice that the gas pressure in one of their four student’s cylinders was dropping faster than was expected, and consequently, missed that this particular student had run out of gas. The student then panicked and bolted for the surface which ended up with them having an arterial gas embolism.”

It would be normal for the majority of Western-cultured divers to believe that the fault would lie with the instructor, especially as I framed your thought processes with the subtitle, ‘An Instructor Makes a Mistake’. 

The instructor would have had a clear level of responsibility to make sure that the event didn’t happen the way it did, and because the student ended up with an out-of-gas situation and an arterial gas embolism, that instructor needs to be held accountable for the mistakes that were made. 

Financial compensation to the diver might be involved. As for the instructor, specific solutions for ways to prevent future mishaps would be standard. The instructor might be advised to be more aware, to monitor students more closely, and follow standards and/or training.

The problem with this approach is that it can miss significant contributory factors. Over thousands of years, we have developed a mindset that searches for the cause of an adverse event so that we can prevent the same thing from happening again. There are two parts behind this sentence that we are going to look at in this article—agency and attribution.

Agency and Attribution

Photo by Alexandra Graziano.

The first is Agency—an agent is a person or thing that takes an active role or produces a specific effect. ‘The instructor failed to notice the faster-than-normal pressure drop.’ In this example, the instructor is the agent. While we can easily identify the action and agent, we cannot determine from this simple statement whether the instructor intentionally didn’t monitor the gas, whether they accidentally missed the increased consumption rate or leak, whether the student didn’t inform the instructor, or if there was another reason. A reader of this short case study would normally assume that the instructor had some choice in the matter, that they were a free agent with free will, and that a professional with training should know better. This assumption can heavily influence how an ‘investigation’ develops from a blame-worthy event to one where wider learning can happen. 

Research has shown that the attribution of agency is subjective and is swayed by a number of different factors including culture, experience, and the language of the observer. Furthermore, the language used and how this frames the event has also been shown to directly influence the assignment of guilt, blame and/or punishment. This is especially the case if the only reports available are based around litigation and insurance claims, as these are purposely written to attribute blame. 

Societally, and developmentally, we believe that the attribution of cause behind an action is important, especially if it is an adverse event because it allows us to identify who or what needs to change to prevent the same or similar events from occurring in the future. In the out-of-gas event above, it might be obvious to some that it is the instructor who needs to change or ‘be changed’!

The Fundamental Attribution Bias

While agency is relatively clear when we describe an event, where this attribution of agency is applied is very subjective. Attribution theory was developed in the 1950s by Fritz Heider in which he described behaviours that could be attributed to internal characteristics or disposition (personality, abilities, mood, attitude, motivations, efforts, beliefs…) or to the influences external to them which were situational in nature (culture, social norms, peer pressure, help from others, organisational pressures, rules, environmental conditions…). For example, a diving student might not perform as expected despite having been given the training detailed in the course materials. This could be because of performance anxiety, lack of confidence, not paying attention to the demonstrations… (internal or dispositional attribution), or it could be caused by an argument they had had at home that morning, mortgage worries, homework which is due, promotion or threat of being fired, or poorly serviced equipment… (external or situational attribution).

Photo by Alexandra Graziano.

This subjectivity is so powerful and prevalent that there is a recognised cognitive bias called the fundamental attribution bias or error. This bias shows that there is a tendency to look for dispositional attribution when an adverse event involves someone else (they didn’t pay attention, they didn’t have the skills or experience), but the tendency to look for situational attribution when the adverse event involves us (high workload led me to be tired, the students were spread far apart, their gauge was in their BCD pocket). “When explaining someone’s behavior, we often underestimate the impact of the situation and overestimate the extent to which it reflects the individual’s traits and attitudes.” As a consequence, it is much easier to ascribe the failure to the individual rather than to look at the wider situation. This aligns with Lewin’s equation, B=f(P, E), which states that an individual’s behavior (B) is a function (f) of the person (P), including their history, personality and motivation, and their environment (E), which includes both their physical and social surroundings. 

Research has shown that culture can strongly influence how agency is attributed. Those from Western cultures e.g. Anglo-American or Anglo-Saxon European, have a tendency to be more individualistic in nature, whereas those from Far Eastern cultures have a more collective view of the world which increases collaboration, interdependence and social conformity. The research also shows that “Compared to people in interdependent societies, people in independent societies are more likely to select a single proximal cause for an event. Western cultures therefore have a tendency to erroneously attribute control and decision to the human actor closest to the event, even if this was not the case. This has huge implications when it comes to litigation and organisational/community learning.

Self-Serving and Defensive Attribution Bias 

When it comes to an adverse event, those cultures that have high individualistic behaviours are more likely to find a way to identify someone other than ourselves as the cause i.e. “the dive center manager didn’t tell me the time had changed, and so I was late for the boat.” Conversely, when we have a successful outcome, we are more likely to look to our own performance and traits (dispositional attribution) rather than the context (situational attribution) i.e. “I had spent time practising the ascents, so my buoyancy was good for the final dive.” without noticing that their buddy was rock solid in the water and provided a very stable platform to reference against. This is known as self-serving self-attribution.

As the severity of the event increases, we mentally distance ourselves further from the traits or behaviours that would have led to this event. “I wouldn’t have done that because I would have spotted the situation developing beforehand. I am more aware than that diver.” This defensive attribution is also known as distancing through differencing.

This is a protection mechanism; if we can shift the blame to someone else because they have a different disposition (internal behaviours/traits), we can convince ourselves that what we are doing is safe, and we carry on with what we were doing in the same way we’ve always done. This might appear to be simplistic; however, much of what we do is relatively simple in theory, it is how it is weaved into our daily lives that makes things complicated or complex. 

Photo by Alexandra Graziano.

Language Matters – Invisible Meanings

The subtitle of the first section “An adverse event occurs. An instructor makes a mistake.” will have invoked a number of mental shortcuts or heuristics in the reader. We will likely make an assumption that the two events are linked and that the instructor’s mistake led to the adverse event. I purposely wrote it this way. That link could be made stronger by changing the full stop to a comma.

Language can have a large impact on how we perceive agency and causality. The problem is that how we construct our messaging is not normally consciously considered when we write or speak about events. As with many other aspects of culture, it is invisible to the actor unless there is some form of (guided) active reflection.

For example, research has shown that there is a difference between how Spanish and English-speaking participants considered the intentional or unintentional actions in a series of videos. In one example, the actor in the video would pop a balloon with a pin (intentional) or put a balloon in a box with a (unknown) pin in it and the balloon would pop (unintentional) as the balloon hit the pin.“The participant descriptions were coded as being either agentive or non-agentive. An agentive description would be something like, “He popped the balloon.” A non-agentive description could be, “The balloon popped.” The study concluded that English, Spanish, and bilingual speakers described intentional events agentively, but English speakers were more likely than the other groups to use agentive descriptions for unintentional events. Another study showed similar results between English and Japanese speakers.

Another powerful bias exists in the form of framing. This is where information is given to another party to influence their decisions and is either done consciously or not. For example, take two yoghurt pots, the first says “10% fat” and the other says “90% fat free”. The framing effect will more likely lead us to picking the second option, as it seems likely it is the healthier yoghurt. If we look at how this applies to diving incidents and agentive language “The diver ran out of gas near the end of the dive.” or “Their cylinder was empty near the end of the dive.” The first appears to put the diver at fault but we don’t know how or why this happened; whereas, the second statement is not personal and therefore allows a less confrontational conversation. Consequently, we must be careful with how we attribute agency as it limits our attention to the context immediately surrounding the person involved. If we want to learn, we have to expand our curiosity beyond the individual and look at the context.

Another example of how language matters and the shortcuts we use is the use of binary oppositions e.g., right/wrong, deep/shallow, recreational/technical, success/error, or deserved DCS/undeserved DCS. While binary modes might work for technical or mechanical systems (work/don’t work), they are not suited for systems involving people (socio-technical systems) due to the complicated and complex interactions that are present. “They didn’t use a checklist.” Is often seen as a final reason why something went wrong, as opposed to asking questions like “What sort of checklist should have been used?”, “When would the checklist normally be used?”, “What were others doing at the time”, “Which checklist? Manufacturer’s, agency’s, or their own?” 

When it comes to these socio-technical systems, we can only determine success or error/failure AFTER the event. If the actors knew that what they were doing would end up as a failure due to an error, they would do something about that ‘error’ before it was too late.

Isn’t this just semantics?

All of this might appear to be semantics, and technically it is because semantics is the branch of linguistics and logic concerned with meaning. “Words create Worlds” (Heschel and Wittgenstein) for the better or worse. Think about how you frame an event or attribute agency because it WILL impact your own and others’ learning.

Look back at the original narrative in the second paragraph, which was purposely written in the manner it was, and consider where attribution has been placed, how it limits learning and what questions you can ask to improve your understanding of the event. We are cognitively efficient creatures, always looking for the shortcut to save energy. However, this efficiency comes at the expense of learning.

In this event, there were many other factors that we needed to consider, many of which would be focused on the limitations of our cognitive system. We CANNOT pay more attention; it has a limited capacity. What we can do is make it easier to prioritise and focus on the most important/and or relevant factors, and we do this by designing systems that take our limited capacity into mind. 

Monitoring four students is going to be at the limits of what is safely possible, especially when other factors are taken into consideration, such as instructor experience, visibility, current, task loading, comfort levels, etc. These factors are readily apparent and their significance obvious after the event, but in real-time with all of the other conflicting goals present, not so. When designing systems and processes, try to apply the key human factors principle: make it easier to do the right thing, and harder to do the wrong thing.

As an example of how this language can manifest itself, have a look at any agency training materials which describe adverse events or incidents, and look to see how agency and attribution are applied, and how little the context is considered. e.g. the following example is from a leadership-level training manual: a supervisor left the dive site before accounting for all of the divers in the group and two were left behind and suffered from hypothermia. The reason given for the abandonment was that the supervisor was distracted. The material then goes on to say that despite the supervisor having normally conducted good accounting procedures, this would not help in a lawsuit as a court would look at the event that occurred not what they normally did. What is missing is understanding ‘how the supervisor came to be distracted’ and what the context was. This would provide a much greater learning opportunity than the normal ‘make sure you account for everyone otherwise you could be in a lawsuit.’ “We cannot change the human condition, but we can change the conditions in which humans work.”—Professor James Reason.


We have a tendency, especially in Western cultures, to want to find out ‘who did it’ and ascribe blame to an individual agent. More often than not, the agent is the person who was closest to the event in time and space. In effect, we play the game of ‘you were last to touch it, so it was your fault’ but this rarely prevents future events from occurring. In reality, divers, instructors, instructor trainers, and dive centre managers are all managing complex interactions between people, environment, equipment and cultural/societal pressures with sensemaking only being made after the event. 

Photo by Peter Gaertner.

To be able to identify a single cause of an adverse event in diving is impossible because it doesn’t exist and yet this is what the language we use focuses on. We look for a root cause or a trigger event for an accident or incident. The research from Denoble et al, which described four stages (trigger event, disabling event, disabling injury and cause of death) of fatalities misses the context behind the trigger events and yet it is still used in incident analyses. Compare this to modern safety investigation programmes which have moved away from a root cause approach to a more systemic approach, like Accimap or Human Factors Analysis and Classification System (HFACS) that take into account systems thinking and human factors principles/models. 

A response from Petar J Denoble’s response, Click Here

There are no formal investigation and analysis programmes or tools in the sports diving sector so any data that is produced is heavily biased by personal perspectives. However, that gap will be addressed before the end of 2021 when an investigation course will be launched to the public by The Human Diver. 

This two-day programme will provide an introduction to a systems- and human factors-based approach to event learning and will be based on current best practices from high-risk industries and academia and then tailored and focused on non-fatal events in the diving industry. There will also be a number of research programmes being developed over the next year or so which look at incidents, their causality and how to report them. The methodology will be relevant to fatalities but these investigations are often undertaken by law enforcement officers or coroners.

Photo by Kirill Egorov.

For the diving community, there is a need to look at how adverse events happen, not by attributing agency to individuals, but to look wider, to the system and the context so that we can understand how it made sense for that human agent to do what they did at the time. Ivan Pupulidy covers this clearly in the US Forest Service Learning Review, “In order to change culture, you have to change the assumptions that drive the culture.”

After note: The article was heavily influenced by the work of Crista Vesel whose referenced paper examined agentive language and how it influenced how the US Forest Service moved from Serious Accident Investigation Guide to a Learning Review. The review allowed more genuine inquiry to occur and find out the real reasons why serious events, including fatalities, occurred. You can find Vesel’s paper here: “Agentive Language in Accident Investigation: Why Language Matters in Learning from Events.”


1. Lexico. Explore: agent. http://www.lexico.com/en/definition/ agent (accessed July 30, 2021). 

 2. Agentive Language in Accident Investigation: Why Language Matters in Learning from Events Crista Vesel ACS Chem. Health Saf. 2020, 27, 1, 34–39. 2020 3. Myers, D. Social Psychology, 11th ed.; McGraw-Hill: New York, 2013; pp 100−117

4. Fausey, C.; Long, B.; Inamon, A.; Boroditsky, L. Constructing agency: the role of language. Frontiers in Psychology 2010, 1, 1−11. 

5. Dekker, S. Why We Need New Accident Models; Lund University School of Aviation: Sweden, 2005.

6. Fausey, C. M.; Boroditsky, L. In English and Spanish Speakers Remember Causal Agents Differently, Proceedings of 30th Annual Meeting of the Cognitive Science Society, Washington, DC, July, 2008. https://escholarship.org/uc/item/4425600t (accessed November 13, 2019).

7. Denoble, P.J; Caruso J.L.; de L Dear G.; Pieper C.F. and Vann R.D. Common Causes of Open Circuit Recreational Diving Fatalities. 2008

8. Learning Review (LR) Guide (March 2017); U.S. Department of Agriculture Forest Service accessed 30 Jul 2021

Gareth Lock has been involved in high-risk work since 1989. He spent 25 years in the Royal Air Force in a variety of front-line operational, research and development, and systems engineering roles which have given him a unique perspective. In 2005, he started his dive training with GUE and is now an advanced trimix diver (Tech 2) and JJ-CCR Normoxic trimix diver. In 2016, he formed The Human Diver with the goal of bringing his operational, human factors, and systems thinking to diving safety. Since then, he has trained more than 350 people face-to-face around the globe, taught nearly 2,000 people via online programmes, sold more than 4,000 copies of his book Under Pressure: Diving Deeper with Human Factors, and produced “If Only…,” a documentary about a fatal dive told through the lens of Human Factors and a Just Culture. In September 2021, he will be opening the first ever Human Factors in Diving conference. His goal: to bring human factors practice and knowledge into the diving community to improve safety, performance, and enjoyment.

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In this article published online on  September 2, 2021, Gareth Lock systematically examines the role of innate attribution biases and language, talks about agency and attribution, and explains why incident investigation may fail to help prevent similar incidents from occurring again. As an example of a failed approach, Lock refers to the paper “Common causes of open-circuit recreational scuba fatalities”, which I co-authored with my colleagues in 2008. While I appreciate Gareth’s work in general and the content of this particular article, I have to point out that our paper never intended to do what Gareth assumes and attributes to it.
1. In our paper, we do not investigate individual incidents. Instead, we attempted an epidemiological analysis based on the reported results of separate incident investigations.
2. We do not claim that triggers are the root causes. We provide clear, pragmatic definitions for all four categories we used in the paper.
3. We never attribute agency in the sense of subjective factors; our only agent is similar to an epidemiological agent, like a mechanical agent of injury (boat hitting diver), CO causing intoxication, and similar.
4. We are aware that there were causes beyond what was reported and that in most cases probably there were multiple causes, and we state it explicitly in the paper.
5. We aimed to identify contributing factors that could be targeted with preventive interventions (which we did not prescribe).
6. We assumed, that although we may never know the primordial cause(s), we still could intervene by preventing the domino effect or by interrupting the chain of events leading towards the fatal outcome. If we were not right in assuming it, why bother with teaching divers all possible corrective measures in an adverse event?I am looking forward to a bright future with much-improved incident analysis methods. I hope that my younger colleagues will have high-quality reports to work with trying to devise the best preventive interventions.

-PJ Denoble