Cave Diving Fatalities
by Jeffrey Bozanic

Based on an analysis of 408 cave diving fatalities, cave diving fatalities can generally be attributed to three direct causes and two contributory causes: (1) Failure to utilize a continuous guideline to the surface; (2) Failure to reserve adequate air reserves for exiting; and (3) Deep diving; (1) Lack of proper training; and (2) Failure to carry enough lights. 385 of these accidents involved divers who had no formal training in cavern or cave diving. Since 1989, 14 divers who had specialized training have died while cave diving. Of these six have been attributed to inadequate training for the environment in which they were diving; four to deep diving; one to poor air management; one to equipment related difficulties; and two to environmental conditions. Introduction: Cave diving is often considered to be one of the most inherently hazardous forms of recreational diving conducted. This is due to the high perceived incident rate of cave diving accidents occurring, as well as the voluminous amount of publicity that such fatalities generate. Hundreds of divers, including many open water instructors, have drowned in caves in the past thirty years. This paper will examine the causes of these accidents, with a special focus on recent fatalities involving trained cave divers. Fatalities Among Untrained Cave Divers: Like with many new pursuits, originally there were no standard practices for scuba diving in underwater caves. Divers exploring these realms for the first time had to develop their own paradigms to maintain safety. Some of these did not work. After a particularly serious run of deaths in 1973, the National Speleological Society formed a committee to determine the causes of these fatalities. Headed by Sheck Exley, the team analyzed all of the incidents for which they could find records. During this original Accident Analysis they found that the accidents could all be reduced to just three direct causes: (1) Failure to utilize a continuous guideline to the surface; (2) Failure to reserve adequate air reserves for exiting; and (3) Deep diving. These elements are listing in the order of significance, with the most common problem listed first. They also recognized two contributory factors to accidents, including: (1) Lack of proper training; and (2) Failure to carry enough lights. To date, 408 fatalities are included in the Accident Analysis files . These findings have in turn formed the basis on which cavern and cave diving training in the United States are based. The five rules for safe cave diving which were derived from this analysis follow: (1) Be trained for cave and cavern diving. This is the single most important rule to follow. Proper training prepares the diver in the techniques, specialized equipment, hazards, and emergency procedures involved in cavern and cave diving. Like in open water diving, there are several levels of training available. It is necessary to have the proper level of training before diving in advanced cave environments. The proper training rule holds true for everyone. The accident files include records of many openwater scuba instructors who have died while attempting to dive in underwater caves. No amount of open water diving experience can prepare one to safely dive in caves. Training in cave diving can be divided into four general areas: lecture/theory, dry land training skills, open water dives, and overhead environment dives. There are also different levels of training, beginning with cavern diving, then progressing on to cave diving with single cylinders, twin cylinders, and advanced cave diving techniques. (2) Utilize a continuous guideline to where an uninterrupted ascent to the surface may be made. Many of the early deaths involved divers who used no guideline to find their way back to the entrance of the cave. Some drowned literally only a few feet from safety, as they groped their way around in the silt they had inadvertently kicked up with their fins. Others perished many hundreds of feet from the exit, hopelessly lost in the submerged maze of passages. A guideline must be used properly to be beneficial. Accidents have occurred in which the guideline was improperly tied off, tied off in the wrong place, or caused the entanglement of the divers during the dive. Again, proper training covers the proper type of line, reels, and techniques for utilizing it. (3) Reserve a minimum of two-thirds of your air for exiting. People drown because they cannot successfully breath water. Thus, maintaining an adequate air reserve is essential. Cave divers use the Thirds Rule to plan their air use. In a broad sense, one third of the initial air supply is used for entering the cave, one third for exiting, and one third is held in reserve for emergencies. Of course, the details of using this requires proper training as well. Note that a minimum of two-thirds of the air supply is saved for exiting. If divers are using dive propulsion vehicles, if the cave has an inward flowing current, or if there are other significant environmental hazards more air than this should be reserved. In some cases only one-sixth of the initial air supply is used for entering the cave, with the remainder saved for exiting and as an emergency supply. A variety of out-dated conventions are occasionally still promulgated. An example of one of these is the "half plus two hundred" rule, where half of the initial air supply plus an additional 200 psi was reserved for the exit. These rules are not safe, and should not be used. (4) Dive no deeper than 130 feet. The national cave diving certifying agencies, like the national open water certifying agencies, all prohibit training in depths exceeding 130 feet. Narcosis, rate of air consumption, and significant decompression penalties all contribute to the hazards faced by the diver descending below this depth. Experience and equipment can reduce the hazard, but cannot completely eradicate it. There has always been a fascination associated with deep diving. There are some very well-known and respected divers who routinely dive deeper than the recommended limit of 130 feet. They are not exempt from the problems connected with deep diving. Some of these esteemed people have died while involved in their endeavors. Despite the publicity some of these diving exploits receive, it is not a safe activity, and should be viewed with that thought in mind. (5) Carry a minimum of three lights per person. Caves are dark. Without the light they carry in, cave divers would not be able to see. Without light, exiting from a cave is much slower, and because time is limited by air supply must be accomplished within a predetermined period. In at least one accident the lack of sufficient light contributed to the deaths. Proper redundancy in equipment is one of the foundations of cave diving. Fatalities Among Trained Cave Divers: One of the results of the accident analysis efforts was that cave diving became much safer. While accidents still routinely occurred, from 1978 until 1989 no fatalities included any individual who had participated in cave or cavern diving training. Prior to 1978 individuals with significant cave diving experience and/or training who died in caves did so because of the depths to which they were diving. This uninterrupted accident free period resulted in a community-wide feeling of invulnerability, which may have contributed to the number of recent incidents involving trained cave and cavern divers. Coupled with this is the push towards "Technical Diving" (including use of enriched air nitrox, mixed gas scuba, diver propulsion vehicles, etc.) which significantly increases the complexity, logistics and associated risk of the activity; as well as the general increase in the number of people receiving training (about 600 through 1978, about 6,000 total to date). Since 1989, fourteen divers having specialized training have drowned in caves. These included three cavern divers, and eleven cave divers. Many of the reasons have been the same as those listed above. Six trained cavern and entry level cave divers have drowned in caves that were clearly beyond their ability and training. These divers broke rules or lacked the skills which would have saved their lives had they participated in the proper training first. This group included all three of the divers who had received cavern diving training, as well as three cave divers who had been out of training for only a short time (less than one week in one instance) from their cave diving course. As with open water diving and cavern diving, no amount of cavern diving experience can prepare one to dive in caves without further instruction. All divers, regardless of the level of training, need to internalize their most recent training by participating in dives similar to those they received in training, before progressing on to more challenging environments. Some very experienced cave divers who have had all the proper training and equipment have died while cave diving. In all cases it was because they exceeded this maximum safe diving depth. Four cave divers fall into this category. Depths for these accidents ranged from 180 fsw to greater than 926 fsw. In addition, two of the divers listed in the first category were also diving in depths exceeding 200 fsw when they drowned. In the opinion of the author, it is expected that this number will grow as the current trend towards mixed gas scuba increases. One fatality was attributed to "creative air management." In this instance, the diver only saved one-fourth of his beginning air supply for the exit, i.e. he used three-fourths entering the cave. His stated opinion prior to beginning the dive was that given the facts that he (1) knew the cave "so well," and (2) the outflowing current in the cave would assist him in exiting, that he did not need to reserve a greater quantity of air. Unfortunately, he apparently got turned around in the system during the dive, silted the passage, and took longer to effect an exit than planned. His body was found on the main line, pointed towards the exit of the system. Had he utilized a proper air management plan, he would have had more than ample reserves to exit safely. Three deaths did not fall into the classification identified above. One seems to have been due to a possible equipment related problem involving the use of a rebreather. In this instance, the diver was found dead floating on the surface while wearing the unit. As this occurred during a long and arduous cave exploration expedition, it is uncertain whether fatigue, environmental conditions, and/or inadequate training also contributed to the fatality. In general, I have been concerned with the proliferation of new technology in cave diving. It seems to me that new techniques and equipment are being too readily embraced by the general cave diving community, before an adequate track record has been established. It is not unreasonable to expect that some future accidents may be attributed directly to the use of nontraditional equipment or techniques. The remaining two deaths stemmed from adverse environmental conditions. One diver died during a cave collapse, which buried the guideline and simultaneously obscured the exit. Another died while diving solo in a cave Pennsylvania. It is hypothesized that her torn drysuit while in the cold water, coupled with poor visibility and loss of tactile sensation caused by wearing neoprene gloves resulted in the loss of the guideline during the dive. Of course, analysis of accidents in often an inexact science. Events are reconstructed from observation of the cave configuration, tales of the survivors or observers on the scene, location and positioning of the corpse, and other evidence. However, without the ability to communicate with the deceased, the true causes of any given accident may remain unknown. For example, in one case involving a cavern diver, it may be that diabetes was a contributing cause to the fatality. In one of the deep diving fatalities, poor equipment maintenance and an unfamiliar dive cylinder configuration apparently contributed to the accident. Conclusion: Generally, adherence to the rules for safe cave diving can be expected to protect a majority of recreational cave divers. But these rules may not prevent a fatality from occurring in the future. There is always the potential for an unforseen accident occurring. In addition, equipment development and testing can always be expected to result in unforseen accidents. However, when followed religiously, the rules listed above have prevented deaths for the nearly twenty years since they were developed very successfully, reducing the level of risk to which divers would otherwise have been exposed. This article can not educate any person to the point where they can follow these rules without further training. This training can be obtained from two agencies in the United States. These organizations both train divers in cavern and cave diving, conduct cave diving workshops, promote cave diving safety, and publish a variety of safety pamphlets and textbooks. For more information you may contact them by writing: National Speleological Society Cave Diving Section (NSS-CDS) P.O. Box 950 Branford, FL 32008-0950 National Association for Cave Diving (NACD) P.O. Box 14492 Gainesville, FL 32604 Acknowledgements: This paper was read in manuscript by Lamar Hires, Training Director of the National Speleological Society Cave Diving Section; I am grateful for his valuable comments. This paper is Number 43 of the Island Caves Research Center, Inc. Safety and Education Series. About the author: Jeff serves as the Executive Director of Island Caves Research Center, a non-profit organization formed for the purpose of conducting scientific investigations in submerged cave systems. His research diving activities have taken him to the Bahamas, Palau, Guam, Mexico, Canary Islands, Antarctica, and other worldwide locations. Jeff was certified as a NAUI Instructor in 1978, and as a cave diving instructor in 1983. He is certified to teach cave diving for the NSS-CDS, NACD, and NAUI. He has published extensively on diving education topics, with heavy emphasis on cave diving safety techniques. He has edited/reviewed many diving textbooks. He served as Chairman of the Board of Directors for NSS-CDS and is a member of the Board of Directors of NAUI and the AAUS. He has received the NAUI Outstanding and Continuing Service Awards; and the Silver Wakulla and Abe Davis Awards for safe cave diving.

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