[3] [Safety is] An active, adaptive process which involves making sense of the task in the context of the environment to successfully achieve explicit and implied goals, with the expectation that no harm or damage will occur.
The remaining fatalities probably arose as a result of a progressive sequence of events involving two or more procedural errors or equipment failures, and since procedural errors are generally avoidable by a well-trained, intelligent and alert diver, working in an organised structure, and not under excessive stress, it was concluded that the low accident rate in professional scuba diving is due to these factors.
While working underwater, divers are subjected to high levels of physical and psychological stress due to environmental conditions and the limitations of the life support systems, as well as the rigours of the task at hand.
Improvements in training standards and equipment design and configuration, and increased awareness of the risks of diving, have not eliminated fatal incidents, which occur every year in what is generally a reasonably safe recreational activity.
Input from various disciplines may be used and the field is considered a mix of engineering and psychology, with four main goals: enhancing safety, comfort and productivity, and reducing and managing errors.
Factors of delegated responsibility and team redundancy are relevant to achieving a good balance between excessive overlap and gaps in awareness.
This second approach has been shown to be more productive of learning from the experience, but can only work within a just culture in which the people involved feel safe to discuss the details.
As the situation overcomes the individual's ability to cope, panic sets in and creates a barrier in the stress response that blocks the decision process.
This model has been suggested as potentially useful for encouraging divers to identify and stay within the limits of their competence and to learn,, practice, and refine the skills likely to be necessary for the dives they plan to undertake as a strategy to reduce the risk of panic in the event of any reasonably foreseeable contingency.
[29] A "near accident", "near miss" or "close call" is an event which had the potential to cause injury, occupational illness, death, or material loss or damage, but did not due to some corrective action.
Three critical stages can be identified in the development of an error into an accident: Equipment, procedures, organization, environment, individual factors and interactions between them are the sources of contributing and compounding events and conditions.
Decompression tables, programs and algorithms that prescribe depth and time limitations are also a subset of procedures, and highlight the unique nature of the hyperbaric work environment.
[1][11]Environmental influences include pressure, cold, currents, surge, and limited visibility, and underwater conditions can change rapidly, often without warning.
The techniques of Human Factor Error Analysis can be applied to diving at all levels of the industry and sport, and can provide insight into why incidents occur and divers die.
Errors of decision can be mitigated by ensuring that the diver has experienced a wide variety of reasonably probable scenarios, preferably as live simulations, or if this is not practicable, as mental exercises.
[12] Depth and visual perception errors are easily made underwater as we are not optimised for the environment, and lack of recent experience can aggravate the problem.
Colour discrimination is also diminished with depth and darkness, and colour-coding becomes an unreliable method of identifying equipment at the times when it is most critical and an error can be fatal.
[41] Some examples of violations: Good communication and team or buddy skills are necessary to limit the risk of a recoverable incident deteriorating into an accident.
[12] Divers need to be aware of their surroundings as they operate in an alien environment and inattention can result in missing a critical cue which could have allowed early response to a problem.
Clearly not all divers are equal in their physical strength and fitness, but people learn to compensate for personal differences, and become accustomed to dealing with situations from their ground state.
Furthermore, they vary with time for the same person, and although the underwater environment reduces the effects of gravity, there are other factors which can make activity more strenuous, such as viscous drag, increased work of breathing and adverse water movements.
Failure to provide this feedback is not a kindness, it is a dereliction of responsibility, as it may lead to potentially dangerous misjudgements of ability to deal with the rigour of the underwater environment, particularly where the specific circumstances are outside the experience of the diver.
[43][44] Kruger and Dunning[43] suggest that those with limited knowledge in a field suffer a double burden: "Not only do they reach mistaken conclusions and make regrettable errors, but their incompetence robs them of the ability to realize it."
[39] Examples:[12] In the operational environment:[45] In the capacity of the individual:[45] In task loading and requirements:[45] In general human nature:[45] While there may be multiple barriers to failure, generally none are completely reliable, (swiss cheese model) When all the barriers to adverse events fail, degradation of performance should when possible allow enough time to recognise the failure and provide sufficient information to allow correct or appropriate decisions, so that appropriate action can be taken in time.
In most cases the body will have been recovered and resuscitation attempted, and in this process equipment is usually removed and may be damaged or lost, or the evidence compromised by inappropriate handling.
The ability to provide documentary evidence showing that correct procedure was followed can simplify the investigation and may lead to more accurate and reliable findings.
The United States Coast Guard, US National Park Service, sheriffs offices and medical examiners have been named as contributing to this problem.
In commonwealth countries such as the UK, Canada, Australia where a coroners inquest is usually held, experts are often called in, evidence is gathered and is made publicly available.
For this purpose, it helps to have well defined goals, which are measurable, specific and meaningful to the dive team, for which the criteria for success are clear, and for which the reward is worth the risk.
[citation needed] Recreational diver training and certification organisations tend to avoid admitting that it may be necessary or desirable to gradually dive beyond one's current limits to develop experience, for fear that this could expose them to litigation, but divers who explore beyond the limits of their current experience, cautiously and intelligently, are the people who break new ground which those same organisations later exploit for profit.