Table 2. Triggers for a scuba diving fatality .

Triggers

Definition: A trigger (as used here) is the earliest identifiable event that appeared to transform an unremarkable dive into an emergency

Environment-related: Relates to the diving environment and may arise from the topography or conditions of the dive site itself or as a result of contact with other users or inhabitants.

• Conditions

Water − e.g., difficulty in dealing with current, swell, surge, chop, water outflow/inlet; visibility, temperature;

Weather − e.g., problem arising from rain, wind, lightning;

• Marine animal contact − e.g., aggression from shark;

• Watercraft-related − e.g., boat impact, propeller injury;

• Entrapment − e.g., tangled in line or net, disoriented in cave or wreck;

• Events triggered from the direct effects of immersion, submersion and/or sensory deprivation, e.g., cardiac arrhythmia.

Equipment-related: Includes a problem with any item of the diver’s equipment that precipitates an accident. The list below is not exhaustive and other equipment may trigger an accident and so can be included.

• Regulator, surface-supplied breathing apparatus or rebreather functional problem leading to gas supply reduction or interruption;

• Buoyancy compensator device (BCD) failure − e.g., sticky inflator, dump valve failure but not including its misuse;

• Weights-related − e.g., unintentional release, unable to be released but not including over- or under-weighting from the outset of the dive;

• Mask − e.g., leak, broken strap, broken/displaced lens;

• Fins − e.g., poor fit, broken strap, loss of fin;

• Exposure suit − e.g., tight wetsuit, flooded drysuit but not including drysuit 'blow-up';

• Cylinder - e.g., valve-failure, slippage but not including problems from gas content or valve insufficiently opened;

• Faulty depth or contents gauge;

• Hose failure;

• Breathing hose entanglement.

Gas supply-related: Includes any problem relating to the on-going supply, purity and suitability of the breathing gas but not loss of gas supply due to equipment failure.

• Inappropriate breathing gas mixture;

• Contamination;

• Exhaustion of breathing gas supply.

Buoyancy-related: Includes buoyancy problems generally related to poor knowledge or skills but not problems arising from equipment failure. It includes factors such as:

• Overweighted or underweighted;

• Poor skills;

• Drysuit 'blow-up';

• Loss of buoyancy control arising from deployment of surface marker buoy.

Exertion-related: Includes problems arising from situations such as carrying equipment, exiting the water post-dive, dragging a heavy object underwater, etc. but not exertion as a result of sea conditions.

Anxiety/stress-related: Anxiety/stress can often be associated with diving, especially in the relatively inexperienced, and can be a trigger for an accident. However, in order for this to be listed as a trigger, it cannot be assumed but must have been observed and reported by a witness.

Primary diver error: Diver error, which is an inherent part of many diving accidents, can be a precursor to or the actual trigger in a sequence. It can be closely associated with another trigger(s) and, in such cases, can be reported in combination.

Other: Includes anything that cannot appropriately be allocated to one of the defined categories. This category should be used sparingly and only after a serious attempt to utilise an existing category.

Unknown: There is insufficient information on which to make a reasonable suggestion of a possible trigger(s).