By Reilly Fogarty
Header image: Original Photo by Sean Romanowski, effects by the team at GUE HQ
There aren’t many technical divers exploring deeper than 153 m/500 ft on a regular basis—the logistical and physiological demands alone make sure of that. The small group of divers who do reach those depths without saturation chambers or other professional accoutrements face a daunting host of new concerns. At these depths, decompression models aren’t as well validated, and dives require precise gas planning and acknowledgement of extreme environmental exposures.
As if decompression illness (DCI) and oxygen toxicity risks weren’t enough, divers must prepare to deal with the possibility that they may get to depth and experience vertigo, confusion, seizures, and a varied list of other neurological maladies—sometimes without warning. These symptoms are the result of high-pressure nervous syndrome (sometimes called high-pressure neurological syndrome) or HPNS. Symptoms of HPNS are highly variable but primarily affect those who descend rapidly to 153 m/500 ft or deeper. HPNS may have played a role in the death of legendary cave explorer Sheck Exley, and it may have caused numerous close-calls in deep cave and wreck explorations. But, the extreme depth required to experience onset has relegated research and education on HPNS to a niche corner of the diving community—one with significant interplay with the commercial saturation diving world and the most extreme sport communities.
The Physiology of Deep Helium Diving
In 1961, G.L. Zal’tsman, who headed the Laboratory of Hyperbaric Physiology, St. Petersburg, Russia, first identified what would eventually become known as high-pressure nervous syndrome. The political climate of the period limited access to his work in the west, so credit for the discovery is often shared with Peter Bennett, D.Sc, who published a paper on the subject in 1965. While politics and international tensions separated them, both researchers described what they called “helium tremors” that occurred during experiments with military subjects. Using gases with the high helium content required to manage narcosis at depth, participants in these studies were observed experiencing uncontrollable muscle tremors upon compression in a chamber.
At the time, it was unknown if this was a function of the helium in their breathing gas or an effect of depth. The term “high-pressure nervous syndrome” originated just a few years after Zal’tsman’s study, when R.W. Brauer identified changes in the conscious states and electroencephalography data from subjects in a chamber dive to nearly 368 m/1,200 ft. In the decades since, several studies further illuminated what we now know as HPNS, primarily as a result of research into deep sea exploration from the 1970s to early 1990s. As it stands now, HPNS is primarily identified by a decreased mental status, dizziness, visual disturbances, nausea, drowsiness, muscle tremors, and seizures in divers rapidly reaching depths of 153 m/500 ft or more, or exploring the extremes of depth closer to 306 m/1,000 ft at any rate of compression while breathing a high helium content gas.
The prevailing theory is that a combination of speed of compression during descent, and the absolute pressure at depth, cause these symptoms. Symptoms are rare during dives above 153 m/500 ft, but dives that exceed that depth, or that reach depth quickly, increase the likelihood of symptom evolution. Symptoms do not appear to correlate to each other, and individual susceptibility is highly variable, which makes predicting onset difficult. Some researchers also theorize that there are two separate conditions caused individually by compression (the symptoms of which diminish at depth) and total pressure (the symptoms of which persist throughout the bottom portion of a dive). This two-part explanation for HPNS symptoms provides some interesting avenues for future research and could help solidify some of the theorized mechanisms underlying the condition, but it has yet to be expanded upon in a significant way.
The mechanism behind HPNS has yet to be proven, but most researchers choose to work upon the basis of a few reasonable theories. The first relies on the compression of the cell membranes in the central nervous system. In this model, the rapid compression of the lipid components of these membranes may alter the function of the inter-lipid structures that facilitate signal transmission within the central nervous system. This change in structure could facilitate hyperexcitability of some nervous system pathways and cause the types of tremors and seizures associated with serious HPNS cases. This membrane compression could also alter the signaling pathways required for motor function and cognition, resulting in confusion and assorted neurological symptoms that sometimes occur in divers with HPNS.
Another model focuses on the role of neurotransmitters themselves, rather than their signaling receptors. The various iterations of this model examine the effects of pressure and varying helium/oxygen exposures on the production or reception of these transmitters. In some ways, this method resembles our understanding of oxygen toxicity mechanisms, which could lead to some interesting interplay between future research projects and the balancing of oxygen and helium exposures at extreme depth. Some of the more promising studies in this area show evidence of NMDA receptor antagonists reducing convulsions in animal models, and describe the effectiveness of increased dopamine release in preventing increased motor activity under extreme pressure in rat models.
A third model focuses on the effect of helium on HPNS risk. This model functions on a yet-unidentified mechanism, but explores the potential distortion of lipid membranes by helium at depth. The data from these studies suggests that high pressure helium—not high hydrostatic pressure—may alter the tertiary structure of protein-lipid interactions and change signaling pathways within the nervous system. Numerous other avenues for research exist in this niche, including projects working on a great number of neurotransmitter related conditions and pre-treatment protocols for HPNS, oxygen toxicity, and possibly related normobaric diseases. Any of these models could prove accurate, but the interplay between the many neurotransmitters makes it most likely that a combination of these models will best illustrate what occurs in-situ.
Experienced firsthand, HPNS is far less academic, but equal parts confounding and terrifying. The variable onset and sometimes ambiguous symptom presentation make it difficult to discern from other conditions, and mild symptoms can be easily written off. By the same token, however, a serious bout of tremors or confusion as a result of a rapid descent to deep water can leave a diver terrified and unable to act. Dr. Richard “Harry” Harris, SC OAM, is a physician and technical diver with years of exploration in deep caves and shipwrecks. His experiences with HPNS mirror that of many. Most often, he’s observed symptoms like trembling hands or loss of coordination that could be attributed to either HPNS or the adrenaline rush of a fast hot-drop from a boat in heavy seas.
On one recent dive to 150 m/490 ft, Harris described becoming temporarily incapacitated on the bottom due to minor tremors, finding himself unable to clip his strobe to the shot line. The symptoms resemble common descriptions of mild HPNS symptoms, but the relatively shallow (in terms of HPNS, at least) depth still gives him pause when he tries to discern the specific cause of the symptoms. Dives past 200 m/656 ft have provided similar conundrums, but Harris has experienced tremors at extreme depths with enough regularity to notice that he is somewhat more susceptible than his regular dive buddy Craig Challen. “This [variation in symptom onset and presentation] has really made me question again the role of the mental state, approach, and perhaps even intentional mindfulness on these symptoms,” explains Harris.
By focusing on gas choices that strike a balance between gas density and the high concentrations of helium that can cause HPNS symptoms, and by descending relatively slowly, Harris has managed to alleviate symptoms on much deeper dives. A recent 245 m/799 ft dive with an intentionally slowed descent gave him none of the same complaints as his rapid descents to shallower water and felt “like a [much shallower] 150 m/490 ft dive.”
It’s worth noting at this point that Harris and Challen are extraordinarily capable and experienced divers, and HPNS is a condition that shouldn’t be taken lightly. Their approach—a combination of conservatism and safety—is likely key to their management of HPNS on extremely deep dives. Other divers, some equally experienced, have not been as fortunate in the past.
Sheck Exley reported a particularly bad case during a dive to 210 m/689 ft, with vision blurred to the extent that he was “looking through small circles with black dots, and started convulsing.” Despite these symptoms, he continued his dive, and proceeded to a maximum depth of 263 m/863 ft. It’s thought that Exley’s eventual death during an attempt to descend past 305 m/1,000 feet in the Mexican Zacatón cave system could have been caused in part by HPNS symptoms exacerbated by narcosis.
Nuno Gomes, a technical diver who holds several Guinness World Records for depth in open water and in caves, has also become intimately acquainted with HPNS, experiencing the following during a world record dive:
“As I descended past 250 m/816 ft, the HPNS set in. At first, relatively mild, then fairly strong. And later on, the symptoms became so extreme that my whole body shook uncontrollably. One other problem was lack of coordination of movement. I felt severely narcosed on my bottom trimix of 3.15/85. It had only a calculated END of 40 m/131 ft. From my experience, a more realistic narcosis level was 78 m/256 ft as calculated using the Total Narcotic Depth (TND). When I reached the tag marked 315 m/1,033 ft at an actual depth of between 322 m/1,056 ft and 323 m/1061 ft, I realized that this was as far as I was able to go. I was not sure that I would be able to return if I went any deeper. At that stage, I was not sure that I would be able to swim up from that depth.”
Gomes’s regular attempts to reach extreme depth made him uniquely prepared to identify symptoms of HPNS as they appeared, but even with his breadth of experience, the effects of the condition could have become lethal if allowed to continue.
Statistically, there just aren’t enough documented cases of HPNS to make for a meaningful analysis, but these incidents can provide a basis for education. The symptom severity and onset variability is enormous, but there are some trends that can be pulled from the stories of Harris, Exley, and Gomes. How to integrate those in your dive plan without meaningful data to back them up, however, falls to personal choice.
Planning for the Future
There are more than a few good reasons not to end this piece with a “how-to” on diving past 153 m/500 ft. With regard to HPNS specifically, the reality is that we just don’t know enough about the mechanisms that cause the symptoms divers experience. What we have is an understanding that high helium content and rapid descents likely contribute to HPNS risk, some people are more susceptible than others, and the symptom presentation is not uniform or predictable. Beyond these fundamental constants, we must piece together what we know from the limited research we do have and the experiences of others.
The data on compression speed appears to be pretty clear: HPNS symptoms may not be entirely preventable, but the risks can be somewhat ameliorated by slowing our descent speeds. There also appears to be an opposing effect between helium and nitrogen content in our breathing gas. This is likely due to changes in the structures of the membranes surrounding our central nervous system caused by helium and other inert gases, requiring divers to balance potential narcotic effects and HPNS risk in gas planning.
Using nitrogen as a protective gas seems counterintuitive, but in some extremely deep dives, adding just 5% nitrogen to a heliox mixture appeared to dramatically reduce HPNS symptoms in divers. However, the extent of practical efficacy remains to be seen. Promising studies researched using hydrogen to minimize HPNS risk, but this avenue of research is prohibitively expensive and logistically challenging due to the inherent fire risk.
The onset of HPNS symptoms also appears to be relatively gradual, although it’s important to recognize that not all data supports this and rapid onset can occur. With slow descent rates and intelligent gas choices, it seems unlikely that divers would experience HPNS severe enough to incapacitate them before they had a chance to turn their dive, but that is not to say that it cannot happen or should be ignored as a real concern. Symptoms of HPNS still haven’t been found to correlate with each other, and not only can new symptoms arise quickly, but also the nature of the ailments means that a diver may not be able to identify symptoms until it is too late to react.
The past decade has failed to provide much in significant data on HPNS as it pertains to recreational divers, certainly almost nothing in comparison to the deep-diving heyday that brought about the COMEX tables and Atlantis projects. Going forward, it seems likely that HPNS will become a greater concern. Technical divers will continue to explore the limits of depth with the widespread adoption of rebreathers, persisting in their search for deeper caves and unexplored wrecks. Hopefully, this ongoing—perhaps even increasing—activity will spur more research into HPNS and the potential interplay between the mechanisms of narcosis and oxygen toxicity. Until then, we’ll have to continue to glean what we can from the data we have and the experiences of the more ambitious among us.
- Naquet, R., Lemaire, C., J.-C. Rostain, & Angel, A. (1984). High Pressure Nervous Syndrome: Psychometric and Clinico- Electrophysiological Correlations [and Discussion]. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 304(1118), 95-102. Retrieved May 21, 2021, from http://www.jstor.org/stable/2396156
- Talpalar, Adolfo. (2007). High pressure neurological syndrome. Revista de neurologia. 45. 631-636.
- Understanding Oxygen Toxicity: Part 1 – Looking Back
- Pearce PC, Halsey MJ, MacLean CJ, Ward EM, Webster MT, Luff NP, Pearson J, Charlett A, Meldrum BS. The effects of the competitive NMDA receptor antagonist CPP on the high pressure neurological syndrome in a primate model. Neuropharmacology. 1991 Jul;30(7):787-96. doi: 10.1016/0028-3908(91)90187-g. PMID: 1833661.
- Kriem B, Abraini JH, Rostain JC. Role of 5-HT1b receptor in the pressure-induced behavioral and neurochemical disorders in rats. Pharmacol Biochem Behav. 1996 Feb;53(2):257-64. doi: 10.1016/0091-3057(95)00209-x. PMID: 8808129.
- Bliznyuk, A., Grossman, Y. & Moskovitz, Y. The effect of high pressure on the NMDA receptor: molecular dynamics simulations. Sci Rep 9, 10814 (2019). https://doi.org/10.1038/s41598-019-47102-x
- High Pressure Neurological Syndrome, DIVER (2012) by Dr. David Sawatzky
InDepth: Diving Beyond 250 Meters: The Deepest Cave Dives Today Compared to the Nineties by Michael Menduno & Nuno Gomes
aquaCORPS:Accident Analysis Report from aquaCORPS #9 Wreckers (JAN95):What happened to Sheck Exley? by Bill Hamilton, Ann Kristovich And Jim Bowden
InDepth: Thoughts on Diving To Great Depths by Jim Bowden
InDepth: Playing with Fire: Hydrogen as a Diving Gas By Reilly Fogarty
Reilly Fogarty is an expert in diving safety, hyperbaric research, and risk management. Recent work has included research at the Duke Center for Hyperbaric Medicine and Environmental Physiology, risk management program creation at Divers Alert Network, and emergency simulation training for Harvard Medical School. A USCG licensed captain, he can most often be found running technical charters and teaching rebreather diving in Gloucester, Massachusetts.
Does The Sport Diving Community Learn from Accidents?
Do we learn from accidents as a diving culture and, as a result, take the actions, where needed, to improve divers’ safety? Though we might like to think that’s the case, the reality is more complicated as human factors coach Gareth Lock explains in some detail. Lock offers a broad six-point plan to help the community boost its learning chops. We gave him an A for effort. See what you think.
by Gareth Lock
Learning is the ability to observe and reflect on previous actions and behaviours, and then modify or change future behaviours or actions to either get a different result or to reinforce the current behaviours. It can be single-loop, whereby we only focus on the immediate actions and change those, e.g., provide metrics for buoyancy control during a training course, or double-loop where the underlying assumptions are questioned, e.g., are we teaching instructors how to teach buoyancy and trim correctly? The latter has a great impact but takes more time, and more importantly, requires a different perspective. Culture is the ‘way things are done around here’ and is made up of many different elements as shown in this image from Rob Long. Learning culture is a subset of a wider safety culture.
Regarding a safety culture, in 2022 I wrote a piece for InDEPTH, “Can We Create A Safety Culture In Diving? Probably Not, Here’s Why,” about whether the diving industry could have a mature safety culture and concluded that it probably couldn’t happen for several reasons:
- First, ‘safe’ means different things to different people, especially when we are operating in an inherently hazardous environment. Recreational, technical, cave, CCR and wreck diving all have different types and severities of hazards, and there are varying levels of perception and acceptance of risk. The ultimate realisation of risk, death, was only acknowledged in the last couple of years by a major training agency in their training materials. Yet it is something that can happen on ANY dive.
- Second, given the loose training standards, multiple agencies, and instructors teaching for multiple agencies, there is a diffuse organisational influence across the industry which means it is hard to change the compliance-focus that is in place. From the outside looking in, there needs to be more evidence of leadership surrounding operational safety, as opposed to compliance-based safety e.g., ensuring that the standards are adhered to, even if the standards have conflicts or are not clear. This appears to be more acute when agencies have regional licensees who may not be active diving instructors and are focused on revenue generation and not the maintenance of skilled instructors. There is very little, if any, evidence that leadership skills, traits or behaviours are taught anywhere in the diving industry as part of the formal agency staff or professional development processes. This impacts what happens in terms of safety culture development.
- Finally, the focus on standards and rules aligns with the lowest level of the recognised safety culture models – Pathological from Hudson. Rules and standards do not create safety. Rules facilitate the discussion around what is acceptably safe, but they rarely consider the context surrounding the activities at the sharp end, i.e., dive centres and diving instructors and how they manage their businesses. These are grey areas. There is a difference between ‘Work as Imagined’ and ‘Work as Done,’ and individual instructors and dive centre managers must both ‘complete the design’ because the manuals and guides are generic, and manage the tension between safety, financial pressures, and people (or other resources) to maintain a viable business. Fundamentally, people create safety not through the blind adherence to rules, but through developed knowledge and reflecting on their experiences, and then sharing that knowledge with others so that they, too, may learn and not have to make the same mistakes themselves.
The proceeding discussion brings us to the main topics of this article, does the diving industry have a learning culture, and what is needed to support that learning culture?
What is a learning culture?
In the context of ‘safe’ diving operations, a learning culture could be defined as “the willingness and the competence to draw the right conclusions from its safety information system, and the will to implement major reforms when their need is indicated.” (Reason, 1997). Here we have a problem!
The industry is based around siloed operations: equipment manufacturers, training agencies, dive centres/operations, and individual instructors. Adopting a genuine learning approach means that the barriers must be broken down and conversations happen between and within the silos. This is very difficult because of the commercial pressures present. The consumer market is small, and there are many agencies and equipment manufacturers that are competing for the same divers and instructors. Also, agencies and manufacturers have competing goals. Agencies want to maximise the number of dive centres/instructors to generate revenue, and one of the ways of doing that is to maximise the number of courses available and courses that can be taught by individual instructors e.g., different types of CCR units. Manufacturers don’t want to realise the reputational risk because their equipment/CCR is involved in a fatal diving accident, but they also want to maximise their return on investment by making it available to multiple agencies and instructors. The higher-level bodies (WRSTC, RTC, and RESA) are made up of the agencies and manufacturers that will inherit the standards set, so there is a vested interest in not making too much change. Furthermore, in some cases, there is a unanimous voting requirement which means it is easy to veto something that impacts one particular agency but benefits many others.
This will be expanded in the section below relating to information systems as they are highly interdependent.
What safety information systems do we have in the diving community?
Training agencies each have their own quality assurance/control/management systems, with varying levels of oversight. This oversight is determined by the questions they ask, the feedback they receive, and the actions they take. These are closed systems and based around compliance with the standards set by the agency – sometimes those standards are not available to be viewed by the students during or after their class! Research has been carried out on some of this quality data, but it appears to have focused on the wrong part e.g., in 2018, a paper was published by Shreeves at al, which looked at violations outside the training environment involving 122 diving fatalities. While the data would have been available, a corresponding research project involving fatalities inside the training environment was not completed (or if it was, it wasn’t published in the academic literature).
As the ex-head of Quality Control of a training agency, I would have been more interested in what happened inside my agency’s training operations than what occurred outside, not from a retributive perspective, but to understand how the systemic failures were occurring. I also understand that undertaking such research would mean it would be open for ‘legal discovery’, and likely lead to the organisation facing criticism if a punitive approach was taken rather than a restorative one.
Safety organisations like Divers Alert Network collect incident data, but their primary focus is on quantitative data (numbers and types of incidents), not narrative or qualitative data – it is the latter that helps learning because we can relate to it. The British Sub Aqua Club produce an annual report, but there is very limited analysis of the reported data, and there does not appear to be any attempt made to look at contributory or influential factors when categorising events. The report lists the events based on the most serious outcome and not on the factors which may have influenced or contributed to the event e.g., a serious DCI event could have been caused by rapid ascent, following an out-of-gas situation, preceded by a buddy separation, and inadequate planning. The learning is in the contributory factors, not in the outcome. In fairness, this is because the organizations do not have to undertake more detailed investigations, and because the information isn’t contained in the submitted reports.
Research from 2006 has shown that management in organisations often want quantitative data, whereas practitioners want narrative data about what happened, how it made sense, and what can be done to improve the situation. Statistical data in the diving domain regarding safety performance and the effectiveness of interventions e.g., changes to the number of fatalities or buoyancy issues is of poor quality and should not be relied upon to draw significant conclusions.
What is required to populate these systems?
There are several elements needed to support a safety information system.
- Learning-focused ‘investigations’.
- Competent ‘investigators’.
- Confidential and collaborative information management and dissemination systems.
- Social constructs that allow context-rich narratives to be told.
Learning-focused ‘investigations’. The diving industry does not have a structured or formal investigation or learning process, instead relying on law-enforcement and legal investigations. Consequently, investigations are not focused on learning, rather they are about attributing blame and non-compliance. As Sidney Dekker said, “you can learn or blame; you can’t do both”. The evidence that could be used to improve learning e.g., standards deviations, time pressures, adaptations, poor/inadequate rules, incompetence, and distractions… are the same elements of data that a prosecution would like to know about to hold people accountable. Rarely does the context come to the fore, and it is context that shapes the potential learning opportunities. “We cannot change the human condition, but we can change the conditions in which humans work.” (James Reason). Rather than asking ‘why did that happen’ or even ‘who was to blame’, we need to move to ‘how did it make sense to do what they did’. ‘Why’ asks for a justification of the status quo, ‘how’ looks at the behaviour and the context, not the individual.
Competent ‘investigators’. As there isn’t any training in the diving domain to undertake a learning-focused investigation, we shouldn’t be surprised that the investigations focus on the individual’s errant behaviour. Even those ‘investigations’ undertaken by bodies like DAN, the NSS-CDS Accident Committee or the BSAC do not involve individuals who have undertaken formal training in investigations processes or investigation tools. A comprehensive learning review is not quick, so who is going to pay for that? It is much easier to deflect the blame to an individual ‘at the sharp end’ than look further up the tree where systemic and cultural issues reside. The education process for learning-focused investigations starts with understanding human error and human factors. The Essentials class, 10-week programme, and face-to-face programmes provide this initial insight, but the uptake across the industry, at a leadership level, is almost non-existent. Four free workshops are planned for Rebreather Forum 4.0 to help address this.
Confidential information management system. Currently, no system allows the storage of context-rich diving incident data outside the law-enforcement or legal system in a manner that can be used for learning. After discussions with senior training agency staff, it appears that as little as possible is written down following an incident. When it is, it is shared with the attorney to enable the ‘attorney-client’ privilege to be invoked and protected from discovery. If internal communications occur via voice, then the potential learning is retained in the heads of those involved but will fade over time. Furthermore, if they leave that role or organisation, then the information is almost guaranteed to be lost.
Social Constructs: Two interdependent elements are needed to support learning: psychological safety and a “Just Culture.” With the former, the majority of modern research strongly suggests that it is the presence of psychological safety that allows organisations to develop and learn (Edmondson, 1999). Edmondson describes numerous case studies where organisational and team performance was improved because incidents, problems, and near-misses were reported. Paradoxically, the more reports of failure, the greater the learning. It was not because the teams were incompetent; they wanted to share the learning and realised that they could get better faster with rapid feedback. They also knew that they wouldn’t be punished because psychological safety is about taking an interpersonal risk without fear of retribution or reprisal – this could be speaking up, it could be challenging the status quo, it could be saying “I don’t know”, or it could be about trying something new and coming up with an unexpected outcome.
The second requirement is a Just Culture which recognises that everyone is fallible, irrespective of experience, knowledge, and skills. This fallibility includes when rules are broken too, although sabotage and gross negligence (a legal term) are exceptions. Neither a Just Culture nor psychological safety are visible in the diving industry, although some pockets are present. To support psychological safety (proactive/prospective) and a Just Culture (reactive), there is a need for strong, demonstrable leadership:
- Leaders who have integrity – they walk the talk.
- Leaders who show vulnerability – talking about their own mistakes including the context and drivers; leaders who want to look at organisational issues inside their own organisation – not just point fingers at others problems.
- Leaders who recognise that human error is only the starting point to understand something going wrong, not the end.
‘…the will to implement major reforms…’
This is probably the hardest part because learning involves change. Change is hard. It costs cognitive effort, time, and money, and this has an impact on commercial viability because of the need to generate new materials, to educate instructor trainers/instructors and divers about the change and do it in multiple languages. Unless there is a major external pressure, e.g., the insurance companies threaten to withdraw support, things are unlikely to change because there aren’t enough people dying in a single event to trigger an emotional response for change. For example, in the General Aviation sector in the US approximately 350 people die each year, but if these deaths happened in airliners, it would mean two to three crashes per year, and this would be considered unacceptable.
In 2022, more than 179 people died diving in the US. (personal communications with DAN)
The most radical changes happen when double-loop learning is applied.
NASA did not learn from the Challenger disaster because it focused on single-loop learning, and when Columbia was lost, the investigation unearthed a lack of organisational learning i.e., double-loop learning. Chapter 8 from the Columbia Accident Investigation Board provides many parallels with the diving industry. The recent changes to PADI drysuit training standards following a fatal dive on a training course provide an example of single-loop learning – fix the ‘broken instructor’ and clarify course training requirements. The double-loop learning approach would be to look at self-certification and the wider quality management across the agency/industry; however, such an approach has significant commercial disadvantages across the board.
Creating a Learning Culture
The previous paragraphs talk about many of the issues we’ve got, but how do we improve things?
- Move to using a language that is learning-based, not ‘knowing’-based. This video from Crista Vesel covers the topic relatively quickly. This includes not using counterfactuals (could have, should have, would have, failed to…) which are informed by hindsight bias. Fundamentally, counterfactuals tell a story that didn’t exist.
- Look to local rationality rather than judging others. Move from who (is to blame) and ‘why did you do that?’, to ‘how did it make sense for you to do that?’. Separate the individual from the actions/behaviours and stop applying the fundamental attribution bias where we believe the failure is due to an individual issue rather than the context.
- Look to break down the barriers between the silos and share information. Ultimately, the stakeholders within the diving community should be looking to create a safe diving environment. Throwing rocks and stones at each other for ‘incompetence’ is not going to help.
- Adopt the Five Principles of Human and Organisational Performance as outlined in this blog.
- Build ‘If Only…’ or something produced for the recreational market, into training programmes at the instructor trainer, instructor, and diver level. This way the culture can slowly change by telling context-rich stories that have ‘stickiness’. However, this requires a fundamental shift in terms of how stories are told and how risk is portrayed in the diving industry.
- Finally, recognise we are all fallible. Until we accept that all divers are fallible and are trying to do the best they can, with the knowledge they have, the money they have, the resources they have, the skills they’ve acquired, and the drivers and goals they are facing, then we are unlikely to move forward from where we are, and we’ll keep choosing the easy answer: ‘diver error’.
InDEPTH: Examining Early Technical Diving Deaths: The aquaCORPS Incident Reports (1992-1996) by Michael Menduno
InDEPTH: The Case for an Independent Investigation & Testing Laboratory by John Clarke
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 450 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.