The study focused on perceived risk, which does not necessarily correspond to actual risk, and the correlation between diver experience and risk perception was not investigated. Analysis of incidents The incidents that are documented and analysed are usually those which lead to serious injury or death. Valuable understanding of the risks of diving can be derived from analysis of such incidents, but they are a small fraction of the potential learning opportunities because for each documented accident there are estimated to be possibly hundreds of undocumented near-misses. Cardiac events account for approximately 28% of diving fatalities. Approximately 60% of these divers had signs or symptoms that could later be identified as cardiac related before or during the dive, but chose to continue to dive. DAN data suggest that limited experience is associated with diving fatalities, with entry level divers and divers certified for less than a year or with limited experience at the highest risk. Divers with very few dives in the previous year, and divers with a very large number of dives (>300) in the previous year are also high risk groups. In the first case due to lack of practice, and in the second case due to overconfidence in their proficiency. A high body mass index may correlate to the risk of a diving emergency becoming a fatality, which may indicate a lack of exercise tolerance that may reduce the ability to successfully manage an emergency. Root cause analysis of incidents shows four phases commonly present during the sequence of events leading to a fatality. These are: the trigger, the disabling agent, the disabling injury and the cause of death. Triggering events in decreasing order of frequency include running out of breathing gas, entrapment, equipment problems, rough conditions, trauma, buoyancy problems and breathing an inappropriate gas. Very few out-of gas incidents are a consequence of equipment malfunctions. Most divers might have survived if they managed their gas supply correctly. Ineffective gas management puts the divers, their buddies and any other diver in the vicinity at risk. Most entrapment fatalities involved an overhead environment, where the diver was unable to make a direct ascent to the surface. While in some circumstances it is possible to enter an overhead environment by accident, it is almost always intentional or due to lack of attention to the surroundings. The majority of the equipment failures leading to fatalities were not due to faults