Risk of SCUBA death & DCI: The Abacus Project

In 1996 three divers died in a single incident on a Sunday afternoon at a popular diving site called Whytecliff Park near Vancouver BC, Canada. At the coroners inquest that followed, one of the contentious questions raised was: How risky is diving in BC? Only speculation and opinion could be offered.

Recreational SCUBA diving is considered by some to be a dangerous, high-risk sport. Others consider it a very safe activity. Calculating the relative risk of sport diving requires accurate information.

At the time of the inquest, accurate information on the incidence of any of diving's risks (i.e., physical injuries, psychological injuries, death) was not available. There was no reliable measure of diving activity or diving risks for the province of BC. In fact, no reliable estimate was available for any geographic area (e.g., country, province, state, etc.) in the world.

In response to the inquest recommendations, a research project was sponsored by the Underwater Council of BC (UCBC). The principal investigators were Dr. Gary Ladd, a psychologist with a special interest in dive psychology, Dr. Victor Stepan, a retired physician with an interest in hyper/hypobarics and Ms. Linda Stevens, a nurse in intensive care and hyperbaric nursing. The objective was to determine the risk of death and decompression illness (DCI) in recreational SCUBA diving in the province. A 14 month field survey counted dive tank fills, hyperbaric chamber treatments of DCI and diving fatalities.

The method and results were presented at the Undersea and Hyperbaric Medical Society (UHMS) Annual Scientific Meeting, June 2002, San Diego, California, USA and published in the South Pacific Underwater Medicine Society (SPUMS) Journal, Volume 32 No. 3, September 2002.

The study produced the following estimates of the risk of recreational SCUBA death & DCI in BC:

  • Incidence of DCI: 0.010% (9.57/100,000 dives)

  • Incidence of Death: 0.002% (2.05/100,000 dives)

  • Incidence of Death & DCI: 0.012% (11.62/100,000 dives)

The following summary of the project is from the SPUMS Journal article:


Gary Ladd, Victor Stepan and Linda Stevens


In order to establish the relative risk of death and non-fatal decompression illness (DCI) in recreational scuba diving in British Columbia (BC), Canada, a field survey was conducted. For 14 months, every dive shop and charter operator in the province of BC was asked to count the number of scuba tanks that were filled for use in recreational scuba diving. For the same 14 month period, hyperbaric chambers reported the number of BC divers treated for non-fatal DCI and the provincial coroners records were reviewed for scuba fatalities. Over the 14 months that scuba tank fill information was collected, an average of 65% (range: 60-71%) of the fill stations reported. Death and DCI incidence rates were calculated based on the 146,291 fills reported by the participating stations. During this same period there were 3 fatalities and 14 cases of non-fatal DCI. The incidence of recreational scuba death was 0.002% (2.05/100,000 dives). The incidence of non-fatal DCI was 0.010% (9.57/100,000 dives). Results are discussed in light of this being the first time a reasonably reliable measure of diving activity has been achieved in a large geographic area over an extended time period.

Click here to link to the full text of the SPUMS Journal article (downloadable as a PDF file)

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