Before & after 2000: How scuba safety shifted

Diving might sometimes seem to evolve at a glacial pace, but while factors such as better equipment and training have been making us safer over time, others such as diver demographics and characteristics have presented a whole new set of challenges.

In a new statistical study, leading diving medical expert Dr John Lippmann has analysed and contrasted the scuba-diving fatalities that occurred in Australia in the last quarter of the 20th century with those from the first quarter of the 21st, to nail down what has changed. 

At least 57,000 Australians are thought to dive annually alongside the many overseas tourists who visit the continent to dive, especially in Queensland. Scuba has not grown as strongly among Australians as it has in some other populations around the world, says Dr Lippmann, the number of entry-level certifications appearing to have peaked around the turn of the 1980s/90s.

Dr Lippmann’s study is based on information on scuba-related deaths taken from the database of the Australasian Diving Safety Foundation, which he runs, and the National Coronial Information System, and takes into account police, witness and post mortem reports.

More female divers

1972 was taken as the starting point for the study because that was when formal regular reporting of Australian scuba fatalities began. In the early period from 1972–1999 there were 236 deaths, while the shorter 2000–2021 period saw 194 fatalities.

Average annual fatalities increased slightly between the two periods, from 8.4 to 8.8. More female divers were among the 21st-century death toll (rising from 17 to 24%), because more women were diving by then.

Training agency PADI says that 33% of its certifications in the first period were for females compared with 39% in the second, so if anything women are under-represented statistically among the fatalities, says Dr Lippmann.

Of most significance is that the median age of diving fatalities rose considerably between the periods, from 33 to 47, as the existing diving population aged. The percentage of casualties among the over-45s rose from 24 to 57%. 

There was a steady increase in the age of casualties over the entire half-century, rising by around five years each decade. This was consistent with longtime divers ageing and a broader and often older population becoming attracted to the activity – and therefore an increased presence of age-related ailments, with their implications for diving safety.

The number of cardiac-related disabling conditions involved in fatal incidents more than doubled (from 12 to 26%) in the later period as divers aged and tended to become more obese, with those who died likely to be more so than the general population.

Another survey by Dr Lippmann reported by Divernet earlier this year revealed that two-thirds of victims in the more than 300 snorkelling and freediving deaths in Australia this century were overweight or obese – and almost half of them had underlying health conditions that would have predisposed them to cardiac arrhythmia-related incidents.

Better training

In the early part of the 1972-99 period less formalised training was available for scuba divers. In consequence fewer deaths in the later period were of uncertified divers (5%, down from 20%) or those undergoing training (6%, down from 8%).

The numbers of divers dying alone under water reduced to some extent in the 21st century. In the earlier period 11% of casualties had set out solo-diving, and only 17% of victims had been accompanied by a buddy during the fatal incident. Half of those who had set out with a buddy had separated before the incident and 18% during it (other incidents were unreported).

Among the 21st-century incidents, 12% of divers had set out solo, 27% were with a buddy when they died and 40% had separated from them before, and 15% during, the fatal incident.

Out-of-gas incidents decreased to some extent between the periods, from 30 to 25%. Improvements in pressure gauges was a probable contributor, while the gradual introduction of BCs from the early 1970s would have helped to bring down primary drowning incidents (from 47 to 36%). 

Weight-ditching

Weightbelt and BC-related fatalities decreased between the periods – though not by that much. In the earlier period, 13% of victims had ditched their weights and 23% had inflated or part-inflated their BC, though of the 34 divers who had done so, only four had also ditched their weights. Mainly in the earlier part of the first period, 57 victims had not been using a BC at all. 

In the later period 17% of fatalities had ditched their weights and 44 divers (32%) were found with inflated or part-inflated BCs, 11 of whom had also ditched their weights. All but three victims had been using a BC.

Weight-ditching numbers “remain far too low and suggest that this potentially life-saving action is still not sufficiently embedded,” says Dr Lippmann. “Adequate training and subsequent periodic reinforcement are necessary to make such actions automatic in the event of a diver in danger of becoming unconscious under water.”

Predisposing factors

The main predisposing factors (PFs) in deaths during the earlier period were inexperience (40%), poor planning (33%), equipment (30%) and health (24%), says Dr Lippmann. The greatest change in PFs between the two periods was the increase in health-related factors, predominantly because divers were older but also reflecting diet and exercise. 

The main planning problems involved deciding to dive in adverse conditions such as rough seas, strong currents or surge, poor visibility and very cold water. The decision to set out solo or to separate likely contributed to 35 deaths. 

The most frequent equipment shortcoming was lack of a BC (mainly in the earlier years) or use of a faulty device. Other problems in descending order included overweighting, regulator or tank-valve faults, absent or overtight wetsuits, faulty or absent pressure gauges and lost fins. 

Failure to use guidelines in silty caves or wrecks led to 10 deaths in the earlier period. Equipment faults were those most likely to result in primary drownings and, to a lesser extent, pulmonary barotrauma / arterial gas embolisms. 

Health-related PFs were identified in 24% of fatalities from 1972-99, and likely directly contributed to 18%. Cardiac-related factors were identified in 30 deaths, two-thirds of which involved severe and often undiagnosed ischaemic heart disease (IHD). 

21st-century PFs

Health-related PFs became the most common in the later period, identified in 53% of casualties and likely directly contributing to 40% of deaths, mostly IHD and other cardiac-related problems. 

Of 163 casualties whose body mass indices were recorded, 43% were classified as obese or severely obese (BMIs were less likely to be recorded in the earlier period).

In the later period inexperience was a likely contributor to 30% of the deaths and planning inadequacies featured in at least 29%, again mainly involving setting out in adverse conditions or diving alone or agreeing to separate.

Pre-existing equipment issues were identified in 21% of the 21st-century deaths. Worst culprits were inaccurate cylinder pressure gauges, followed by faulty regulators, gross overweighting, faulty BCs, leaking cylinder-valves, incorrectly configured cylinder/regulator combinations, incorrect gas-mixes or contamination and faulty CCR sensors.

Equipment-related accidents are nowadays more likely to be down to poor maintenance or unfamiliarity, says Dr Lippmann.

The age factor

“Although there has been no significant increase in average annual deaths between the periods 1972–1999 and 2000–2021, there has been a substantial increase in the casualties’ ages and the proportion of females,” he concludes. 

“The increase in training availability and ubiquitous use of BCs and cylinder pressure gauges over time has likely been instrumental in reducing primary-drowning events. 

“However, the increase in age of participants combined with dietary and exercise factors is accompanied by a higher prevalence of cardiac disease and obesity, leading to a rise in the frequency of cardiac-related fatalities. Improved health education and surveillance, especially of older divers, are essential to reduce such deaths.

“In addition, improved dive-planning, including choice of dive-sites and assessment of prevailing and potential conditions, as well as tighter buddy systems, incremental experience and embedded emergency surfacing protocols, should reduce fatalities, especially in less experienced divers.”