BSAC

NDC Diving Incidents Report
2005

Overview

2005 has seen the highest ever number of UK incidents reported; a total of 441. The chart below shows the total of UK incidents reported annually over the last 15 years and it can be seen that, after a jump in the early 90s there has been a steady increase of about 11 incidents per year with perturbations of plus or minus up to 50 incidents per year around this trend line. It is not known if this increasing trend is the result of more incidents, more diving, better data capture or a combination of some or all of these factors.

The distribution of reported incidents is shown in the following chart. As can be seen, 67% of these incidents have occurred in the summer period. This is totally consistent with previous years, reflecting the increased number of dives that take place during the warmer weather.


Incidents by category
The incident database categorises all incidents into one of nine major categories, and the following chart shows the distribution of the 2005 incidents into those categories.
The highest number of incidents (110) relate to 'Decompression Illness (DCI)' and this is consistent with previous years, although there does seem to be a decline from a peak of 144 in 2002. Many of the 'Injury and Illness' incidents are also thought to be DCI related, but they are reported by the RNLI as 'Diver illness' and the cause of the illness is not defined.
Last year I highlighted the rise in the number of incidents associated with abnormal ascents. This year's report contains 98 ascent related incidents, the highest number ever recorded and a 23% increase over the 2004 total, which was itself a record.
The following analysis reveals some of the issues:-

Basic nature of the report:-
81 Rapid ascents
28 Missed stops
Clearly some incidents relate to both the above

Causal factors are:-
17 Delayed SMB, mask, fin problem
12 Drysuit or BCD issues
11 Weight related issues
10 During training
9 Out of air
8 Regulator free flow
Again some have a combination of the above factors

When all of the above causal factors are excluded 47 incidents (50%) remain where a simple loss of buoyancy control seems to have been the cause. Without any of the above perturbing factors being present divers have simply been unable to correctly control their rate of ascent. Poor training and lack of skill are the only explanations. These are avoidable problems and instructors should make this a priority area for attention.
Many DCI cases have their roots in these problems; they have been recorded under the DCI heading but the causal factors are often the same, so the actual number of abnormal ascents will be significantly higher than shown above.

'Boating and Surface' incidents are the third largest category. Recent years have seen a decline in the number of these incidents from a maximum of 124 in 1998 and the 2005 numbers indicate a levelling out at just under 90. The decline in these incidents and the increase in 'Ascent' related incidents has displaced 'Boating and Surface' from its traditional second place.
Although the numbers are very low, this year saw a number of cases where divers were struck by boats and/or propellers; resulting in very serious injuries in one case and a very lucky escape in another.



Fatalities
17 fatal incidents occurred in the UK during the 2005 incident year. This is entirely in line with the average of 17.8 fatalities per year over the last ten years.
2004 saw 25 fatalities and raised concerns that we might be experiencing the beginnings of a trend of increasing fatalities. At the time the BSAC argued that this unfortunate number was simply the result of natural perturbations of very small numbers in a very large sample, compounded with the timing of the incidents and the timing of our incident year. The 2005 total seems to support this argument.
The 17 includes two double fatalities. 5 of the 17 were BSAC members.
The factors associated with these fatalities can be summarised as follows:-

• Two cases involved people who suffered a serious medical problem (typically a heart attack) whilst they were diving. There is a third case which may well also be included in this group when the full facts are made known.
• Three cases involved divers who were, or who became, negatively buoyant and sank. In two cases divers were at the surface, in difficulties, but were unable to remain at the surface and sank before they could be recovered. Last year 8 out of the 25 fatalities were affected in this way.
• Four cases involved separation.
  In each of these cases the separation was not planned.
  Two cases involved three divers diving together. In one case the separated diver survived and the remaining two became one of the double fatalities. In the other case a problem arose during the ascent, two surfaced but the third did not.
  The third case involved a separation during an ascent where one of the divers did not make it to the surface.
• One case involved a hose failure which led to an out of air condition.
• Four cases involved solo diving. In each case they intentionally dived alone. One case involved a cave diver who became tangled in ropes. Two cases involved very deep dives; one to 60m and the other to 68m.
• Two cases involved divers running out of breathing gas.
  One was due to an equipment failure as defined above. The second was a result of divers going back into the water, after a dive, to recover lost equipment.
• · Three cases involved rebreathers.

Often multiple causes were involved in an incident and in nine of these fatal incidents there is insufficient information available to be clear about the exact chain of events and root causes.

As stated above, four of the year's fatalities involved solo diving and to throw more light on these events I conducted a study of the database. The current database goes back to 1998 and it contains 138 fatal incidents (UK). 8 of these incidents involved double fatalities, giving a total of 146 deaths. Of this total, 19 relate to solo diving. This means that 13% of our fatalities were solo divers and we can be sure that this is very significantly higher than the fraction of dives that are conducted solo. People might be tempted to point at the double fatalities and argue that 8 lives would have been saved if the incidents had been solo dives. This may be true but every year we report a number of incidents where an attentive buddy has clearly saved another's life by taking the appropriate remedial actions. My guess is that these cases outnumber the double fatalities by a factor of five or more.

Finally there were three reported fatality overseas. Two cases involved the deaths of BSAC members. The third case involved BSAC members in the death of a non member.

Incident depths
The following chart shows the maximum depth of the dives during which incidents took place categorised into depth range groupings.


The pattern of depths in the 0m to 50m range is very similar to that normally seen and reflects the amount of diving that takes place in these depth ranges. The number of incidents reported in the greater than 50m range is 10, which is in line with previous years. However 2 of these 10 were fatal incidents, again indicating the risks associated with deep diving.

The BSAC advises that no air dive should be deeper than 50m, and that dives to 50m should only be conducted by divers who are appropriately trained and qualified.
The recommended limit for divers trained to Sports Diver standard is 35m and then only when they have received appropriate training for diving at this depth.
The BSAC recommends that mixed gas diving should be to a maximum depth of 70m and then only when the diver holds a recognized qualification to conduct such dives.


The next chart shows the depth at which the incident started.


Inevitably the data are biased towards the shallower depths since many incidents happen during the ascent or at the surface. Critical among these are the DCI cases where almost always the casualty is out of the water before any problems are noted. This partially explains the large occurrence of 'Surface' cases as this includes divers with DCI who have left the water.
Other surface incidents involve boats and boating incidents.

Diver Qualifications
The next two charts show the qualification of those BSAC members who were involved in reported incidents.
The first looks at the diver qualification.


These data are in line with the normal pattern of previous years and, to some extent, reflect the number of divers in these qualification grades.

The next chart shows an analysis of incident by instructor qualification and again it is consistent with previous years.



Divers' use of the Emergency Services

Divers' use of the emergency services shows a monthly distribution aligned to the distribution of all incidents, and is clearly correlated with the number of dives that are taking place.

Our demands upon the Coastguard service seem to be on a very gentle increase, having risen by about 40 cases during the last 8 years, an overall rise of about 20% in that time period.


Our call upon the RNLI in the 2005 incident year is up from 2004, and incident numbers seem to have increased back to the level of those reported at the end of the 90s


In 2005 137 incidents involve the use of helicopters, and this is the highest number recorded. Helicopters are tasked to support searches for missing divers and to transport divers with DCI to recompression facilities. In the mid 90s helicopters were involved in about 20% of diving incidents; this number has steadily risen to about 35%. It is clear that we are seeing a general increase in the availability and use of helicopters for these tasks.


Decompression Incidents
The BSAC database contains 110 reports of DCI incidents in the 2005 incident year, some of which involved more than one casualty. When these multiple cases are counted the result is 120 cases of DCI.
This number continues the decline in cases of DCI from a peak of 173 individual cases reported in 2002 and returns us to the typical levels reported in the late 90s.

An analysis of the causal factors associated with the cases for 2005 indicates the following major features:-

• 40 involved rapid ascents
• 30 involved diving to deeper than 30m
• 28 involved repeat diving
• 19 involved missed decompression stops
• Some cases involved more than one of these causes.

Whilst cases of DCI may have declined, as reported earlier, cases of abnormal ascent (rapid ascent and/or missed stops) have significantly increased, and it may just be a case of good fortune that these abnormal ascents have not resulted in DCI.

Conclusions
Key conclusions are:-

• Reported incidents are in line with the trends of recent years.
• The number of fatalities is in line with the norms of previous years.
• Fatal incidents associated with solo and trio diving continue to feature.
• Incidents associated with abnormal ascents have risen dramatically and attention must be given to training in this area and the continuous practice of ascent skills.

As has been stated many times before, most of the incidents reported within this document could have been avoided had those involved followed a few basic principles of safe diving practice. The BSAC publishes a booklet called 'Safe Diving' (latest edition May 2002). This booklet summarises all the key elements of safe diving and is available to all, free of charge, through BSAC HQ.

Remember you can never have too much practice and the further you stay away from the limits of your own personal capabilities the more likely you are to continue to enjoy your diving.


Please browse through the details in this report and use them to learn from others' mistakes. They have had the courage and generosity to record their experiences for publication, the least that we can do is to use this information to avoid similar problems.


Finally, if you must have an incident please report it on our Incident Report form, available free from BSAC HQ or via the BSAC website.
As always, your anonymity is assured - great care is taken to preserve the confidentiality of any personal information recorded in BSAC Incident Reports.

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Abbreviations | Overview | Fatalities | Decompression Incidents | Injury/Illness | Boating &Surface Incidents | Ascent Problems | Technique Problems | Equipment Problems | Miscellaneous Incidents | Overseas Incidents | Numerical &Statistical Analyses