Compilation of Technical Diving Incident Database
Jeffrey Bozanic, M.A., CHT
Much has been learned from the analysis of recreational diving incidents and
fatalities. Information gleaned from such analyses has resulted in modified
training protocols, diving practices, equipment development, and
certification standards. In the technical diving subset of recreational
diving, the only major standardized effort to collect such data has been
managed by the cave diving training organizations in the United States. They
have collected data on 478 fatalities in submerged cave systems, which has
also substantially improved training and diving protocols. A recent effort
has begun to collect similar data covering other areas of technical
recreational diving. Data collection includes incidents involving divers
breathing gases other than air, using semi-closed and fully closed circuit
rebreathers, penetration into enclosed environments (ice/wreck), and
participating in planned staged decompression diving activities. An interim
report of such data is presented, as well as an overview as to what
information is being collected.
In 1969 Dr. John McAniff of the University of Rhode Island began collecting
information on fatalities occurring to scuba divers in the United States
(1-4). His data incorporated incidents involving the general recreational
diving community. His timely work began during the period that recreational
diving began to grow at an exponential rate. The information generated by
his activities resulted changes to training standards and training
Today we see similar growth in what is termed "technical diving." While the
diving community has not agreed upon a specific definition of the term, it
generally denotes any activity that is considered to be beyond the scope of
"recreational" diving. These may include such diving activities as deep (130
fsw), decompression, cave, ice, and penetration wreck diving. It may also
include modes of diving considered "unusual," such as the use of helium
based breathing gases, multiple cylinders on a single dive, and semi-closed
circuit or fully closed circuit rebreathers. The definition remains fluid,
as activities which might be considered "technical" at their introduction
become mainstream activities. Examples might include the use of buoyancy
compensators, low power inflators, dive computers, and enriched air nitrox
Many of these activities and modes of diving have long been considered
standard in commercial diving sectors, and as such have had a variety of
procedures and standards adopted for their use by that community (5).
However, use in the recreational sector is relatively new, with standards
for training and techniques for those users in a correspondingly less
developed state (6).
A systematic look at both fatal and nonfatal incidents involving technical
diving activities in the recreational diving sector could result in
improvements similar to those prompted by McAniff's early work for general
recreational diving. The only technical diving activity that to date has
been specifically targeted has been cave diving.
The Cave Diving Model:
In 1973 the National Speleological Society Cave Diving Section (NSS-CDS)
began collecting and compiling information on scuba diving fatalities
occurring submerged cave systems. The objective for the project was to
determine why such accidents were occurring, with a view towards prevention
of the same (7). In the same era, Dave Desautels of the National Association
for Cave Diving (NACD) undertook a similar project (8-9). These activities
paralleled the work that McAniff was conducting.
The cave diving data revealed that all fatalities (n=194 cases) could be
attributed to just three causes (7). These results became known as "accident
analysis." As a direct result, the training programs for cavern and cave
diving were completely overhauled, and structured around the findings of the
data collection. Guideline use became mandatory, depth limits (150 ffw) were
implemented as acceptable cave diving practice, and dive techniques were
modified to reserve minimum air reserves for exiting (2/3 of beginning air
supply, known as the "Thirds Rule").
Continued collection and evaluation of cave fatalities has since resulted in
the addition of two causes. Data (n=248 cases) implicated lack of training
and failure to carry a sufficient number of lights (minimum of three) as
contributory factors (10). This again lead to modification of training
standards, programs, and equipment requirements. Recently, further work has
generated discussion on possible additions to generally accepted cave diving
practices (11-14). In short, compilation and evaluation of fatalities
involving divers in underwater caves has benefited that community by
providing the basis for concrete suggestions for development of practices
and training standards for the activity, resulting in decreased levels of
Technical Diving Database:
Only limited attempts have been made to examine incidents involving
technical divers, and these have been limited primarily to fatalities
(15-17). While the Divers Alert Network (DAN) is compiling fatalities and
incidents from the recreational diving community, their focus is not
primarily on technical diving. However, their data does include cases
involving technical divers, and some attempt has been made to evaluate these
At the annual meeting of the NSS-CDS in May 1999, it was decided to extend
the cave diving accident files program to other forms of technical diving.
This decision was reached because of the trend to utilize other forms of
technical diving in the pursuit of exploring, mapping, and enjoying
The existing data reflects such activity, as several fatalities involve
problems with multiple gas mixes, new equipment, and other aspects of
technical diving. However, because of the limited use of technical diving
within cave environments (the primary constraining parameter for data
collection), it was recognized that it would take too long to compile
sufficient data enabling meaningful interpretation. Therefore, the decision
was made to extend data collection to technical diving activities in
environments other than submerged caves.
Simultaneously, it was recognized that as much or more knowledge could be
learned from nonfatal as fatal incidents. Therefore the project has been
broadened to incorporate information on serious, but ultimately nonfatal
events. These could include incidents requiring hyperbaric treatment
(embolism or decompression sickness); resulting in unconsciousness while
underwater (hypercapnia, hypoxia, oxygen toxicity); of significant trauma
(caustic cocktail, fractures, etc.); out of breathing gas events; or other
events from which lessons might be learned.
The program is being pursued jointly by the NSS-CDS and the NACD, under the
direction of the author. Results of the project will be disseminated as
warranted. Recognizing that these data will benefit not only the cave diving
community, but the technical and recreational diving communities, as well as
providers of medical care to the same, presentation and publication venues
will be selected accordingly.
At this time there are 97 non-cave related incidents in the database. Most
of these have been sourced from published accounts of incidents in a variety
of magazines catering to technical divers. Other cases have been taken from
accounts found on Internet list servers, personal communications, and
hyperbaric facility treatment files. As this time it is considered premature
to make any generalizations regarding causes of technical diving accidents.
The validity and effectiveness of this project will be directly proportional
to the quantity and quality of the data obtained. The author would be
grateful for any assistance with data compilation. The most difficult task
is incident identification and raw data collection. Medical care providers
often have first-hand access to this data that is otherwise unavailable. The
following data on any incident is requested:
Even partial reporting is beneficial. All information will be maintained
confidentially. Please report any incidents involving recreational technical
P.O. Box 950
Branford, FL 32008-0950
P. O. Box 14492
Gainesville, FL 32604
E-mail: JBozanic@hqonline.net Fax: (714) 842-2552
This paper is Number 49 of the Island Caves Research Center, Inc. Safety and
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