Summary of RF4 Paper: Human Factors in Rebreather Diving

Between 20 and 22 April 2023, hundreds of rebreather divers, scientists, military divers, commercial divers, and rebreather manufacturers attended Rebreather Forum 4. The videos from the conference were made available last year, and through tireless work, Dr Neal Pollock has completed the editorial work and produced a 290-page workshop proceedings which you can download from here.

I gave a presentation covering the topic of Human Factors in Rebreather Diving. The paper is available in the proceedings from pages 57-69. This blog provides a summary of the paper and covers five main themes.

• The Complexity of Rebreather Diving
• The Role of Systems Thinking in Safety
• The Need for a Just Culture and Psychological Safety
• The Importance of Non-Technical Skills
• Overcoming the Challenges of Implementing Human Factors

Introduction

Rebreather diving, while offering an incredible way to explore the underwater world, comes with inherent hazards that are often underestimated. Note hazards replaces risks because risk has both positive (reward) and negative (hazard or loss). Unlike open-circuit scuba diving, rebreather diving involves a more complicated set of equipment and a deeper understanding of the technical and cognitive/social/cultural systems at play. The true challenge in improving rebreather safety lies not just in mastering the technology but in understanding the human factors that significantly influence safety and performance.

Human factors, a term widely recognised in high-risk industries like aviation and healthcare, are crucial in rebreather diving (see HSE report RR871). These factors include everything from the cognitive abilities and limitations of the diver to the culture within diving teams and organisations. Despite their importance, human factors have not been systematically integrated into rebreather diving training or equipment certification although some instructors and dive centres mandate the Human Diver's Essentials programme as pre-learning. This gap has very likely contributed to incidents that could have been prevented with a better understanding of how human performance interacts with the complex systems involved in rebreather diving. The documentary If Only... shows this stark reality in place.

In this blog post, we will explore five key themes that highlight the importance of considering how human factors impact the safety and performance of rebreather diving. By the end, you'll see why understanding and applying human factors isn't just a good idea—it's should be considered essential for the future of safe rebreather diving.

Theme 1: The Complexity of Rebreather Diving

Rebreather diving is inherently more complicated than traditional open-circuit scuba diving. Given the 'hidden' failure modes, understanding how the various systems and human physiology interact is critical. The complexity of the equipment operation and change in buoyancy management for many divers increases the cognitive load on divers, making it easier for errors to occur and less likely they will be trapped. Unlike open-circuit systems, which are relatively straightforward and where failures are fairly obvious (no gas, gas escaping, loss of buoyancy), rebreather systems and their operators managing oxygen levels, carbon dioxide removal, and maintaining the correct pO2 in the breathing loop. While a single failure isn't likely catastrophic, multiple failures (including cognitive failures) can lead to life-threatening situations like hypoxia, hyperoxia or hypercapnia.

The challenge is not just in understanding how the equipment works but also in managing the human aspects of operating such complex equipment. For example, divers must be able to monitor and respond to changes in their equipment configuration or status while also managing their own stress, cognitive limitations, or social/peer pressures. This is where human factors come into play. By understanding the limits of human cognition and how social conditions change behaviours, we can design better training programs and surface/in-water procedures that reduce the likelihood of errors and increase the likelihood they are recoverable.

To increase resilience (i.e., safety), rebreather diving demands a higher level of teamwork and communication, this facilitates the sharing of information and making effective decisions under pressure. This requires not only technical skills but also strong non-technical skills, such as situation awareness and decision-making. Given the complex nature of rebreather diving operations, it is crucial to consider and apply the science of human factors at every level—from equipment design to training and team dynamics and post-incident/accident analysis.

Theme 2: The Role of Systems Thinking in Safety

To improve safety in rebreather diving, it is essential to adopt a systems-thinking approach. Systems thinking involves looking at the big picture, understanding how different elements within a system interact, and recognising that safety is an emergent property of the entire system—not just its individual components. In the context of rebreather diving, this means considering how equipment, training, organisational (dive centre, training agency, and dive team) culture, and individual behaviours all contribute to safety.

A key principle of systems thinking is that errors are often symptoms of deeper issues within the system, rather than the result of individual failings. For example, if a diver makes a mistake, it may be tempting to attribute the error to personal incompetence, like Brian who forgot to turn his O2 back on before jumping in the water. However, a systems-thinking approach would look deeper, examining factors such as the quality of training, the design of the equipment, and the organisational culture that may have contributed to the error.

This approach shifts the focus from blaming individuals to understanding and improving the system as a whole. It doesn't mean shifting the blame to an agency or a manufacturer, i.e., blame upwards instead of downwards, it is about learning. By identifying and addressing the contributory and contextual factors, we can create more resilient systems that are better able to withstand the inevitable challenges and uncertainties of rebreather diving. Systems thinking also encourages the development of systems that can fail safely—minimising the impact of any errors that do occur.

Theme 3: Just Culture and Psychological Safety

One of the most significant barriers to improving safety in rebreather diving is the lack of a "just culture." A just culture is one where individuals feel safe to report errors and near-misses without fear of punishment. This type of culture is essential for learning from mistakes and preventing future incidents. Unfortunately, the diving community, like many other high-risk industries, often operates in a culture of blame, where individuals are held personally responsible for errors, rather than looking at the broader systemic issues. A challenge in diving regarding a just culture is that divers don't know what it is. Research has shown a diverse perspective of the meaning of this critically important topic (page 64 in the thesis which is visible in the show notes here). 

Psychological safety, which is closely related to just culture, refers to the belief that it is safe to take interpersonal risks, such as admitting mistakes or asking for help. If there is a psychologically safe environment, divers are more likely to speak up when they notice something wrong, whether it's a potential safety issue or a flaw in the training process. This openness is critical for continuous learning and improvement. As Clive Lloyd said, "You can't fix a secret."

Creating a just culture and promoting psychological safety requires a shift in mindset at all levels of the diving community—from individual divers to training agencies and equipment manufacturers. Leaders play a crucial role in setting the tone for this culture, by responding to mistakes with a focus on learning and improvement rather than punishment. By fostering a just culture and ensuring psychological safety, we can create an environment where divers feel empowered to contribute to safer diving practices. Further to this, unless you accept 'human error' (or the variability of performance) as being normal, then it is likely impossible to create a just culture.

Theme 4: The Importance of Non-Technical Skills

Non-technical skills (NTS) are often overlooked in rebreather diving, yet they are just as important as technical skills in ensuring safety and success given their interdependent nature with technical skills. NTS include skills like communication, teamwork, decision-making, leadership & followership, and situational awareness. These skills are essential for managing the complex and dynamic situations that can arise during a dive.

For example, effective communication is critical for co-ordinating actions among dive team members, especially in high-pressure situations. Situation awareness allows divers to develop and maintain an accurate understanding of their environment and the status of their equipment, enabling them to make better informed decisions quickly - they are able to be better 'predictors' of the future. Decision-making skills help divers evaluate options and choose the best course of action, not just in a crisis, but also on a normal dive. If we understand how we make decisions, we are less likely to be 'fooled' by biases.

Training programs for rebreather diving should place a greater emphasis on developing these non-technical skills, alongside the technical skills required to operate the equipment. This can be achieved through scenario-based training, where divers practice responding to realistic situations that require both technical and non-technical skills. Many diver training organisations allow single students on a CCR class with the instructor acting as the buddy. However, this dynamic is not like it would be for the majority of post-class diving, and so teamwork should be taught. By improving NTS, divers will be better equipped to handle the challenges of rebreather diving and to work effectively as part of a team.

Theme 5: Overcoming the Challenges of Implementing Human Factors

Despite the clear benefits, implementing human factors in rebreather diving is not without its challenges. One of the biggest obstacles is the lack of standardised training and certification programs that include human factors. While some training agencies have started to incorporate human factors into their programs, there is still a long way to go before these practices are universally adopted. There is a perception that this is just common sense, but it is more akin to learning to dive Open Water, and the basic non-technical skills need to be learned, developed, and coached. For example, OW online eLearning programmes are approximately 10-12 hours. Essentials is 3.5-4 hours and gives all divers a common language and framework to operate with. 

Another challenge is the cultural resistance within the diving community. Many divers and instructors are accustomed to a traditional approach to training and may be skeptical of the need to focus on human factors. Overcoming this resistance requires education and awareness-raising efforts, as well as leadership from within the community to champion the importance of human factors.

Finally, there are practical challenges related to the design of rebreather equipment and the cost of implementing human factors-based training programs. However, the potential benefits in terms of improved safety and performance make these investments appear worthwhile depending on where you are in the 'system'. Safety does not exist at a component (equipment), personal (instructor/diver), organisational (training agency/dive centre), or environmental (physical, social, cultural) level, but at the convergence of these domains at the system level. Equipment is not safe unless you consider the other domains... 

Summary

Rebreather diving is an activity that takes place in an inherently hazardous environment with 'hidden' failure modes. As such, rebreather diving operations demand a deep understanding of both technical factors and human factors. By embracing a systems-thinking approach, fostering a just culture, and emphasising the importance of non-technical skills, the community can significantly improve safety and performance in rebreather diving. While there are challenges to implementing these practices, the potential benefits are too significant to ignore.

As we look forward (one of the themes from RF4), it is essential that the diving community comes together to address these issues. This means breaking down the silos between manufacturers, training agencies, and divers, and creating an environment where learning from mistakes is valued over assigning blame. Note, learning doesn't require a fatality or serious injury, learning exists in many different forms. By taking this approach, we can increase the likelihood that rebreather divers are resilient to the threats they face, be those technical, physiological, or social.

If we don't act now, when? Practically, we don't need to wait for a "politically relevant event" to force change, but ethically and morally we likely will have to wait for that change to come from the organisational levels within the industry. At a middle or low-level, we can create the groundswell needed, and apply the existing knowledge and practices to make human factors a central part of the rebreather diving experience, ensuring that every dive is not only successful but also uneventful.

You can download the full proceedings from here

The videos from all of the presentations are available here, this is mine.

 
Gareth Lock is the owner of The Human Diver, a niche company focused on educating and developing divers, instructors and related teams to be high-performing. If you'd like to deepen your diving experience, consider taking the online introduction course which will change your attitude towards diving because safety is your perception, visit the website.