Diving Risk Management

Every time we dive, our body and mind are exposed to conditions far removed from those accustomed to which we are accustomed. As human beings, we have adapted, through millions of years of evolution, to live and work on land. We need artificial supports (regulators, tanks, and dive suits) and specific preparation to survive underwater. Today’s technology guarantees high-quality equipment, and professional instructors ensure adequate preparation. Despite this, there will always be a certain level of risk whenever we step into what Jacques Cousteau called “the world of silence.”
Let’s start our analysis of dive risk management with some basic concepts. What is “risk”? And what do we define as “safe”?
The risk is given by the probability that a given adverse event will occur and the severity of the impact of that event (Fig. 1).

For example, the risk of losing a fin when entering the water depends on the probability of a strap breaking (adverse event) and the fact that we cannot continue diving (consequence). In this case, the risk is considered modest because even in case of loss of the fin, there will be no serious adverse consequences for the diver (under normal diving conditions). The value of the risk for a regulator malfunction is quite different; in this case, the severity of the impact can be very high.
In general, it is possible to develop risk matrices in which adverse events are classified according to the probability of occurrence and the level of harm that results from them. The U.S. Navy has created one of these matrices considering four levels of likelihood and five levels of severity, impacting divers ranging from very limited to fatal. Of the sixteen possible combinations in the matrix, only three are considered negligible, showing that most diving errors can cause severe damage (Fig. 2).

The concept of “safe” does not indicate a total absence of risk but rather that this risk has been carefully assessed, that all mitigation strategies have been undertaken, and that, in the end, we are aware of and accept the possible consequences. For this process to take place efficiently, it is necessary to be mindful of the existence of a risk, to have the ability to understand all its implications, and finally, not to be coerced into accepting it.
From the analysis of over a thousand diving accidents, the most frequent type of error (31%) was related to a knowledge problem. In practice, the diver did not know that a problem was occurring or, even if he realized something was wrong, he did not have the technical ability to understand what and how to remedy it. This situation could be solved with more extensive training to increase one’s knowledge of underwater activity. Immediately after (28%), applying a wrong rule was identified as the determining cause of the accident. The origin of this error is most likely a lack of experience; under stress, a diver who is still inexperienced can get confused and perform an incorrect procedure. To overcome this problem, it would be advisable to apply “over-learning,” i.e., learning the techniques so profoundly that you can act instinctively in case of need. Finally, practical errors are involved in 16% of accidents. In this case, the diver understood what was happening and tried to apply the correct procedure but did not have the material capacity to do so. The solution is to take the time to assimilate new concepts. You don’t become an expert diver in a week.
Another exciting aspect of diving risk management is that the dynamics of most diving accidents follow what is defined as the “Pareto principle,” named after Vilfredo Pareto, an Italian economist of the nineteenth century. This principle states that most events originate from a minimal number of causes. In practice, therefore, by controlling a limited number of parameters, it would be possible to reduce the incidence of many diving problems. For example, poor buoyancy control and mismanagement of respiratory gases have been identified as causes of accidents at 60% and 40%, respectively. Focusing diving training on these two points would allow for a substantial reduction in risk.
Moreover, a diving accident almost always results from a series of minor “deviations” from the norm that originate a chain of events that degenerate into an uncontrollable situation. Identifying such events in the bud is the winning strategy to avoid accidents. For example, a poorly closed weight belt is not a big problem, but neglecting it could lead to its fall and consequent loss of buoyancy control, with dire consequences.
One of the best ways to manage risk is to apply checklists, and a UK study of 4,800 events showed that if appropriate pre-dive checks had been carried out, 29% of accidents would have been avoided.
Incorporating a minimum risk analysis into the dive preparation is a valid strategy to increase safety and divers’ awareness.