Annual Diving Report - Divers Alert Network

4. DIVE FATALITIES
Figure 4.3-5 shows breathing gear and breathing gas. Scuba was used in 94 percent of cases
and most frequently with air (78 percent). Nitrox and trimix were used in six cases each.
Rebreathers were used in four cases and surface-supply in one.
Percent of Fatalities
80
60
40
20
0
Scuba Air Scuba
Nitrox
Scuba
Trimix
Rebreather Surface-
Supply
Figure 4.3-5 Breathing gear and gas for U.S. cases (n=73).
4.4 Analysis of situations and hazards
We explored each case according to: (a) the phase of the dive in which it occurred; (b) the
chronological chain of events ending in death; and (c) the buddy system used.
Cause of death (COD) was usually the best defined characteristic of a diving fatality, but
preceding events were frequently more relevant to understanding what happened. In reverse
chronological order, we defined the key events as COD, disabling injury, disabling agent, and
trigger. Where possible, we attempted to identify these events for all cases. The disabling injury
was not necessarily the COD but was ultimately responsible for death. The disabling agent was
the cause of the disabling injury, and the trigger was the event that began the sequence that
ultimately culminated in death.
4.4.1 Fatalities by dive phase
Dive phases included: (a) on the surface before diving, (b) descent, (c) on the bottom, (d) ascent,
and (e) on the surface after diving. Figure 4.4.1-1 shows the distribution of fatalities by dive phase
and indicates that most deaths appeared to occur for divers on the bottom. Fatalities often began
and evolved over several dive phases. Table 4.4.1-1 shows the phase when problems started
and when the diver lost consciousness. Forty-two divers lost consciousness underwater, but their
problems may have started earlier. No information was available in 34 percent of cases.
Annual Diving Report: 2006 Edition 51