SteamerDetroit, Lake Huron, Michigan

94OCT- A deep-wreck diver made an emergencyascent from a depth greater than

200 f/61 m and got severely bent during a mixdive on the U.S. Detroit, a paddle wheeler sunk in 1854. The injureddiver had ten years experience diving deep wrecks in the Great Lakes,having logged 200-300 dives, according to one of his companions. TheDetroit was discovered last year and lies 18 miles offshore in anarea of Michigan known as The Thumb.

The Diver was using trimix and independentdoubles. He switched tanks and regulators when one of his regulatorsbegan to free flow. The diver decided to make an emergency ascent toan oxygen supply staged at 20 f/6 m for decompression, but ascendedto the surface instead. The support crew administered oxygen andcalled a Coast Guard helicopter for medical evacuation. The diverunderwent repeated decompression treatments and is walking today, butsuffers residual damage from the incident.



94OCT- A diver died during a charter expeditionto the freighter Ethel-C, sunk in 1960 off the Virginia coast. The33-year old diver experienced a problem during his finaldecompression stop on the second dive of the day, lost consciousnessand sank when other divers could neither inflate his BCD nor hangonto him. His body has not been recovered.

The former military diver, was reportedly ingood physical condition and had extensive experience diving, althoughhe had not done deep diving previously. He and two partners werediving air on the wreck, which rests at 185 f/57 m for a minute, thenascended to 170 f/52 m for 19 minutes. A decompression schedule ofthree minutes at 30 f/9 m on air, six minutes on O2 at 20 f/6 m and18 minutes on O2 10 f/3 m was followed. The divers had a five-hoursurface interval between the two dives.

After about two minutes into their 10 f/3 mstop, the diver’s head feel back and his regulator came out ofhis mouth. One of his two partners came to assist, but the other wasnot in the vicinity, apparently following a different decompressionschedule. The partner tried unsuccessfully to inflate his BC using apower inflator button, but for an unknown reason could not, and washaving difficulty holding on to the unconscious diver, who was notclipped to the station. Another diver came to assist and the partnerascended to the surface to notify the boat crew of the problem. Theassisting diver could neither inflate the BC nor hold onto the diver,who sunk to the bottom. The surviving partner suffered decompressionillness and had to be flown out by helicopter for treatment.

Neither the partner nor the assisting divertried to remove the diver’s weight belt, and the partner did notattempt to orally inflate the BC. While the reason the BC did notinflate is unknown, one member of the group speculated that eitherthe diver left his power inflator hose detached intentionally,without informing his partner, or could have run out of air, althoughthe other divers believe he had 1,000 psi remaining in his tank. Onereport attributed the death to O2 seizure, while another theory isthat the diver suffered from a heart condition calledPrinzmetal’s angina, which has been linked to the other divingincidents.


MayanCenote, Mexico

95APR- Two experienced cave divers ran out ofair and died after missing a turn while trying to exit a cave dive inMexico. The two were among a group of seven cave divers who hadbroken into three teams for a 45-minute dive on air at depths nogreater than 60 f/ 18 m. The pair was on the third team to enter thecave. Besides making an incorrect turn while trying to exit, thedivers failed to use safety reels to mark a jump and apparentlymissed or disregarded a series of line markers pointing the directionto the exit.

On their way into the cave, all three teamsused a main tunnel known as B. They passed in sequence through aT-turn, where the divers expected a jump. However, instead the cavecame to a T, with three line markers marking the correct direction toturn while returning to go to the exit. A member of the second teamrepositioned one of the markers to make it more visible.

The third team into the cave called their diveearliest as planned, since the first two teams were stronger swimmersand wanted to penetrate further. The two divers then headed back, butturned in the wrong direction at the T, apparently missing all threeline markers at the spot. Their mistake led them 300 f/91 m to theend of B tunnel, where another route leads to the A tunnel. Thedivers headed into the A tunnel, which also led to an exit, crossinga visual gap without setting up a safety reel to mark theirpath.

The divers then made a series of errors,apparently missing several indicators that should have told them thatthey were following a different path than the one they'd taken in.The divers made it to the end of the line marking the start of the Atunnel, about 30 feet from an exit. Rather than exiting, the teamheaded back into the A tunnel, passing as many as 14 line markerspointing back toward the entrance they'd just left. The divers thenswam past the unmarked jump which might have led them back to theother dive teams.

When the third team did not return from thedive, the other five divers notified local authorities and asked forhelp. Later that day, the divers returned to the cave and recoveredthe bodies of the two divers. Their moves were reconstructed by theother members of the team, one of whom had entered the A tunnel aftercompleting his dive in an attempt to find the missing divers. Henoticed silt at the entrance, indicating that the missing team hadrecently been there, but because of low air had to turn back beforegoing far enough into the tunnel to find them. One of the divers whodied was 38 and had made between 75 and 100 cave dives; the other was45 and had some 150 cave dives.

A cave diving instructor with the groupcommented that the series of errors apparently made were inexplicablegiven the level of experience between the two divers.


Whathappened to Sheck Exley?

by Bill Hamilton, Gordon Daughtery, AnnKristovich, and Jim Bowden.

Excerpted with permission from the UnderseaHyperbaric Medical Society's newsletter, "Pressure."

On 6April94, cave diver and explorer SheckExley died attempting to reach the bottom of the Zacaton sink hole innortheastern Mexico. This physiological analysis relates theconditions and events of the dive as well as we can reconstruct them,and speculates on possible causes of his death. It is not intended toendorse or glorify record-setting exploration nor to judge it in anyway; that stands on its own merits as the prerogative of theexplorers. These are the facts of the case as well as we can put themtogether, plus some speculation.

Exley, 45, died while exploring a sink hole orcenote, at Zacaton, located in northeastern Mexico, not far fromMante, the site of his previous record dives. At a depth of 1080f/332 m or more, Zacaton may be the deepest water filled pit in theworld. Exley was diving with Jim Bowden as part of Bowden's "ElProyecto de Buceo Profundo" project. On the day of the fatal dive,Bowden and Exley dived independently, but at the same time and withsimilar techniques.

Bowden and Exley descended on separate weightedguidelines 25 to 30 feet apart. Bowden started a few seconds beforeExley; the descent was expected to take 10 to 12 minutes. The diverskept track of the line visually. From a decompression and gasmanagement point of view, the more rapid the descent the better, buta rapid descent potentially may exacerbate the effect of HighPressure Nervous Syndrome (HPNS) (See aquaCorps Journal N8, "Highpressure nervous Syndrome," by R.W. Bill Hamilton). Both divers hadexperienced HPNS symptoms on previous dives and planned to slow theirdescents to less than about 100 f/min (30 m/min.) at about 680 f/229m. Air was breathed by both divers to 290 f/92 m at which point Exleypause to "stage" his air cylinder by clipping it to the line at 290f. Bowden used a small "pony" cylinder carried on his back as his airsupply. The divers switched to a "travel" mix, trimix 10.5/50 (10.5%O2, 50% He, bal. N2), for the descent from 290 to 580/89-179m.

Both Bowden and Exley selected a bottom mixthat would produce a tolerable PO2 of less than 2.0 atm and anequivalent narcosis depth (END, the equivalent depth on air) of 274f/84 m at 970 f/298 m. These levels were accepted by both diverssince the exposure to maximum depth would be brief (not that a higherPO2 would minimize the lengthy decompression at the cost ofincreasing the risk of CNS oxygen toxicity. Technical divers arerecommended to run their working POs at less than 1.4 atm. SeeaquaCorps N7, "Blueprint For Survival Revisited"-ed.). Bowden usedtrimix 6.4/31 and Exley used trimix 6/29 (mixed by adding helium toair). Both divers used gas from the back mounted bottom mix supply tofill their buoyancy compensators (BCs).

Sheck carried a total of about 369 cf (standardcubic feet) of bottom mix in two large back mounted tanks. He alsohad two side mounted tanks (aluminum "80s" filled 3600 psi) of trimix10.5/50. Jim carried 426 cf of trimix 6.4/31 in two back mountedtanks and in one side mounted aluminum "80" tank. A second sidemounted "80" tank contained trimix 10.5/50. Tanks filled withspecific decompression mixtures had been staged on each individual'sdescent line during the two days prior to the dive. The extendeddecompression called for mixes of air, enriched air nitrox,argon-oxygen, and oxygen.

It is difficult to overemphasize the importanceof gas management and careful gas planning for a dive of thismagnitude. At 30 atmospheres (970 f/298 m) the amount of gas in anormal 72cf scuba tank is reduced to less than 2.5 effective cubicfeet-good for 2 or 3 minutes, less if exercising. Bowden and Exleyfollowed a rigorous pattern of breathing, taking slow, deep breathsat a practiced rate in order to optimize the tradeoff between excessgas consumption and hypoventilation-which lead to CO2 buildup. Asmall change in the breathing pattern, especially in rate, canquickly alter usage calculations.

Bowden checked his gas volume about 874 f/268m. He had expected to have approximately 1800 psi (pounds per squareinches) at this point and had only 1000. He realized the need turnthe dive and arrested his descent at the 898 f/276 m mark. On theline during decompression, Bowden observed Exley's unuseddecompression tanks and correctly assumed that Exley had notsurvived. The support team realized this 18 minutes into the divewhen the trail of bubbles on Sheck's line disappeared. Bowdencompleted his nine plus hours of decompression, surfaced withshoulder pain, and was treated with oxygen, corticosteriods, andhydration.

The positive analysis does not adequatelyexplain the shortage of gas. In 1993 December, Bowden dove to 776f/238 m in the same system, confirming his anticipated gas usage, ashad previous dives to 722 f/222 m and 489 f/150 m. Sheck’s gasusage in an earlier dive in Bushmansgat confirmed that his gasmanagement technique was adequate.

Bowden concedes that even a slight elevation inbreathing rate, beyond his practiced 5-6 breaths/min., would accountfor the added gas consumption on this dive. Both divers had plannedto slow their descents at 679 f/209 m using their BCs which consumedprecious bottom mix. Additionally Exley, who had started the divewith less volume than Bowden, slowed at 291 f/84 m to drop his airtank used in the initial stage of the dive.

the day after the dive, topside team memberKristovich and others returned to recover equipment from both lines.Exley’s was heavy with his staged steel tanks, and plans weremade to raise the entire line with a pulley assist from the surface.Two days later, during this process, Exley’s body surfaced. Theline was wrapped several times around both arms and the valves of hisside mounted bottles. Entanglement did not involve the back mountedbottles, valves, mounting plate, or BC. His mask and all otherequipment was in place. He did not have a regulator in his mouth. HisBC contained gas and the inflator was functional. His wrist mounteddive computer revealed a maximum depth of 879 f/270 m. The gauge ofhis back mounted tanks read 500 psi, the lowest pressure that wouldhave effectively supply gas to the diver’s regulator at thebottom depth. One regulator of his two side mounted tanks wasunhooked and the pressure was 500 psi. The second tank had 3600 psiand the regulator was stowed. A later analysis of the gases for theoxygen component revealed accuracy in the expected mixes. An autopsywas ordered but nothing reported explained the accident. Three dayspassed since the death, and that combined with the effects ofimmediate decompression made a confident postmortem analysisdifficult.

What went wrong?

We will never know for sure. Most likely Exleyreached a point where he was unable to inflate his BC mechanicallywith compressed gas and wrapped the line around himself to stabilizehimself while sorting things out. His maximum depth was 879 f/270 m.Exley may have ascended 75 feet or more, but that cannot bedetermined for certain from the recovered line, since it was cutduring removal from the water. The manner in which the line waswrapped around his upper body makes it unlikely that the entanglementcould have happened by accidentally, even if a convulsion hadoccurred. Exley’s experience level makes this unlikely aswell.

If we accept this, the main uncertainty is whyor how he became so low on gas. It was not like Exley to fail tocheck his gas supply, but the physiological stress of the rapidcompression (HPNS) could have occupied him enough that he was notaware of his situation until it was too late. The equivalent narcoticdepth of his mix was approximately 242 f/75 m at a depth of 879 f/270m, an air depth easily within his comfort level, but also a potentialcontributor to the probable cascade of problems. The gas density was14 g/l at this depth, the equivalent of breathing air at 334 f/106 m.Resistance to breathing plus intentional slow breathing undoubtedlyresulted in an increased level of CO2, possibly high enough to impairperformance.

Exley had used some of his trimix 10.5/50travel mix for the descent, but would not have consumed gas down to500 psi on that portion of the dive. The travel mix could have beenlost to free flow, but more likely Exley breathed it when the supplyof trimix 6/29 was exhausted. This was a "hot" mix at 879 f/270 m,where the PO2 would be 2.9 atm; the equivalent narcosis depth was 423f/130 m, and the gas density 21 g/l, equivalent to breathing air at487 f/154 m. It could have been breathed during a quick ascent ifeverything else were under control. However, with the contributoryfactors of the neurological hyperactivity buildup, it is possiblethat central nervous system (CNS) oxygen toxicity causedincapacitation or a convulsion. A phenomenon known as "deep waterblackout" has caused many divers under less stress to loseconsciousness without convulsing. Its exact physiological course,including the cause, is not known.

In addition, equipment failure cannot beentirely ruled out. A fee flow of the primary regulator at depthwould have contributed to a very rapid loss of volume and consequentreduction of vital gas reserves.


The most likely sequence of events was thatExley got behind on his gas management, ran low on bottom gas, andcould not control his buoyancy so could not ascend. The cause is notclear, but a combination of factors could include stress of HPNSexacerbated by the narcotic effects of nitrogen and CO2. Hestabilized his position by wrapping his descent line around his arms,was forced to switch to his trimix 10.5/50 at a depth of at least 800f/246 m, and was subsequently incapacitated by the prevailingconditions of HPNS, hyperoxia, exertion, CO2 buildup, and nitrogennarcosis.

The accident could have occurred as aphysiological consequence o fan illness, known or unknown, that couldlead to death or incapacitation on any day in an individual involvedin strenuous activity. Likewise mechanical failure, such as somethingthat could cause unexpectedly fast gas consumption or loss, cannot beruled out.

R.W. Bill Hamilton, Ph.D., is a physiologistand editor of Pressure. C.G. Daugherty, M.D., is a diving doctorspecializing in occupational medicine. Ann Kristovich, DDS, is anoral surgeon and diver and medical officer for the Zacaton project.Jim Bowden is a diving instructor at the University of Texas andproduced much of the material used in this article.


BakerstonMine, Harpers Ferry, West Virginia

94JUL- A certified cave diver apparentlyembolized and died when his DPV trigger stuck in the "on" positiondragging him to the ceiling of the cave following a gas switch fromtrimix to air at a depth of 200 f/61 m on the return leg of anexploration run. Prior to the switch, the diver had drained hisdoubles-violating the "thirds rule"- and was forced to share gas withhis partner and swim for safety when his reserve cylinder regulatorfailed to function- the regulator hose being too short to permitscootering.

The team’s objective was to explore beyondthe end of the existing permanent line at approximately 1650 f/503 mat a depth of 285 f/88 m. the team began the dive by motoring in 900f/274 m to a depth of 200 f/61 m where they switched from air totrimix. The dive continued to a landmark known as "The Rock" at adepth of 250 f/78 m at 1200 ft/366 m. At this point the cave slopedto 270 f/83 m over a distance of several hundred feet (61 meters).The diver dropped his DPV due to the limited depth rating of thevehicle and swam as his partner slowly motored along. The end of theline was reached without incident at a depth of 285 f/86 m and theteam added another 150 f/46 m of line to a depth of 305 f/94 m. Thedive was called and the exit began.

The team returned to the staged DPV at 270 f/83m at which point the diver attempted to switch to his reservecylinder, his doubles being empty. Apparently, his regulator wouldnot deliver any gas. Realizing there was a problem, his partnerhanded the diver a regulator from one of his two trimix stagebottles, however, the short hose made it impossible to motor so theteam swam their DPV’s back to The Rock. At this point, the diverswitched back to his air stage and the team motored approximately 300f/91 m up the ledge to the big room at a depth of 200 f/61m.

Once they entered the room, his partner felt aDPV blast and saw a flash of light. He turned to find the diverunconscious on the ceiling- the DPV running circles around him. Thetrigger was stuck "on." There was blood in the diver’s mask. Hecut away the DPV and tried to hold a regulator in the diver’smouth with no response. The partner then attempted to tow him out buthad to leave the diver to complete his own decompression.

The recovery team had no problems locating andextracting the body. All equipment was functioning properly,including all regulators. The doubles were empty and the single 80with trimix was full with the regulator working properly.

The diver had a reputation for violating thethirds rule, had previously run out of gas on at least three cavedives, and had experienced "deep water blackout" (where a deep airdiver is rendered unconscious) at 210 f/65 m while switching frombottom mix to air during a previous dive to the site and survived. Anastute dive partner held his regulator in his mouth until he regainedconsciousness.

Lusitania,Kinsale, Ireland

94AUG-Two months after the Tapson expeditionwas completed without incident, a 37 year old diver "blew up" to thesurface from a 280 f/86 m trimix dive on the Lusitania, incurringsevere injuries.

After descending to the wreck, the diver’spartner began to lay line form a descent line. The two becameseparated when the diver’s stage cylinder came undone from hisharness. He tried unsuccessfully to reattach the cylinder and in theprocess, became severely entangled in the line. He then dropped acutting too that he had intended to use to disentangle himself. Hispartner returned to assist and cut him free, but the diver apparentlypanicked and blew up the surface legs first. He was diving on atrimix 12/26 (12% O2, 26% He, balance N2) and his surface to surfaceinterval was about 12 minutes.

The injured diver was flown to the Navalrecompression chamber at Haulbowline near Cork, Ireland. On arrival,the injured diver was weak but moving all limbs with goodpreservation of cortical function and absolutely no evidence ofpulmonary barotrauma. His condition continued to worsen and he wastreated with little success.

The diver had been certified for nitrox andtrimix diving less than four months before his accident and had beenadvised by his instructor that his experience level was insufficientto attempt the Lusitania in 1994 without more experience. It isunknown whether the diver, who is now a quadriplegic, will ever walkagain.


SheckExley: Preliminary Accident Report

On 6 April 1994, Sheck Exley and Jim Bowden ofAustin, Texas, submerged on a deep cave dive that both hoped wouldcarry them to a new world of cave diving depth record of 1,000 f/307m. Exley, the holder of the current mixed gas open circuit record of881 f/271 m set last year at Bushmansgat, South Africa, did notreturn from cave.

The dive site known as Pit 6350 or Zacaton islocated near the small town of Aldama some 60 miles north of Tampico,Mexico. The pit is approached first by traversing a 600 foot longunderwater passage with a maximum depth of 50 f/15 m to reach a largeround open air lake. The divers could not enter the pit directlybecause of the 60 to 70 foot sheer cliffs surrounding the lake. Thelake had been previously plumbed around its circumference by Exleyand found to exceed 1,000 f/307 m on all sides. Two separate descentlines were rigged, one for Exley and the second for Bowden. Whilethey both dived at about the same time, the separation of the lineswas such that both divers were relatively unaware of each otherduring the dive.

When Exley’s bubbles did not reappear onthe surface when expected, safety diver, Mary Ellen Eckhoff descendedto a ledge at 270 f/83 m to check, and found Exley’s dive tablesfloating upward. No bubbles were seen ascending from depth. Laterwhen the descent lines were being hauled up, Exley’s body waspulled to the surface. His depth indicator showed that he had reached904 f/278 m.

It is unlikely that the course of eventsleading to this tragedy will be known with certainty. A careful, moredetailed analysis of the facts known about the dive, the dive plan,and an analysis of potential causes of the accident is beingundertaken as Exley would have wanted. This analysis will bepublished in a future issue of aquaCorps.

This accident marks the passing of one of theworld’s greatest cave divers. All his friends and family tookcomfort knowing that Sheck passed away doing what he loved most. Orperhaps, Sheck is as he was in life, merely one step ahead of therest of us, exploring the caves in the Great Beyond. He will bemissed.

-submitted by John Zumrick.

HuautlaExpedition: Fatality Report

On 27MAR1994, British cave diver Ian Rolanddied whilst exploring the terminal sump in Sotano San Agustin, partof the Systema Huautla, in Oaxaca, Mexico. A member of the expeditionteam, Roland was diving the prototype rebreather system underdevelopment by Bill Stone.

At 08.00 on the 27th, Ian had dived from CampFive for a 380 m/1246 f penetration. Dive time was 53 minutes at amaximum depth of 26 m/85 f.

At 11.00 Kenny Broad continued the exploration,surfacing in a large air bell at 430 m/1410 f. The chamber wasapprox. 20m wide and 20m high (65 feet x 65 feet) with largesandbars. There was not sound of running water or air movement. Kennyreturned to base without exiting the water. At 16.00 Roland set outto explore the chamber. He estimated a return time of three hours butsaid not to worry for six.

At 19.00 Broad, concerned by Roland’snon-appearance, began to assemble the second rebreather rig. At 22.00he set out to Camp Three to alert the support party. They returned toCamp Five in due course and completed the assembly and checking ofthe second rig. At 12.15 on 28MAR, Broad began the dive through tothe chamber. He carried emergency medical supplies (Roland wasdiabetic), food and bivouac equipment. At 12.41 he surfaced in thechamber and noted foot-prints on the sand bar. He swam alongside thebar, in clear water, and continued beyond its end for 10 m/33 f atwhich point he located Roland’s body resting on its right side.Resuscitation was futile.

Broad noted that the line reel appeared to havefallen out of Roland’s hand. Four out of five tanks were fulland the control system was functional. The mouthpiece was in closedcircuit position and out of the mouth; the O2 "setpoint" was 0.5atmospheres; the O2 control valve was in manual shut off position andthe PO2 was 0.17 atmospheres (heliox 14/86). There was no sign ofstruggle or distress. The body was recovered by team members,assisted by Mexican cavers and members of a British expedition, in anoperation which took six days.

Observations during the recovery showed thatthe control system was still active and the heads up and buddydisplays were both flashing red, indicating a PO2 below 0.21 atm. Theleft diluent tank was empty. Black box data records that wereretrieved from the rig, show that the tank was emptied over a sevenminute interval following Roland’s loss of the mouthpiece as therig attempted to maintain counterlung volume. Functional tests weremade on the rig back at the base. All systems were operational andwithin specification.

Roland had eaten a normal breakfast in themorning buy was suffering from mild diarrhea. He had taken two foodbars which were not eaten. There was not sign that Roland had doffed& donned the rig when leaving the water. These items had combinedthe weight of approximately 140 pounds, therefore traversing theairbell would have involved a significant exertion. The oxygeninjector unit on the rig was manually switched off. This is a commonprocedure upon surfacing which conserves oxygen. Normal procedurewould have been to re-enable the unit upon re-entering thewater.

Given that his rebreather appeared to be fullyfunctional, it was initially presumed that Roland’s death wasdue to operator error based on the closed position of the O2 valve.However, black box data clearly indicates that at the time of whatwas apparently an uncontrolled descent from the surface to 9 f/2.8 m,the PO2 of the breathing mix was 0.24 atm, i.e. not hypoxic,indicating Roland’s blackout was due to some other cause. Theobserved PO2 of 0.17 atm resulted from purging of the gas processorwith 14/86 heliox during the descent. It’s subsequent stabilityat 0.17 atm indicates that Roland was not breathing form the rigfollowing initiation of the descent.

Based on his dive line, it was clear thatRoland was returning to the sand bar from the head of Sump 2 afterapparently realizing something was wrong. Given that Roland was adiabetic and had not recently eaten; that heavy exercise, and mentalimpairment was present (evidenced by the failure to re-enable to O2valve) it has been concluded that the black out was caused byhypoglycemia and/or related events such as arrhythmia or seizure.Roland was extremely meticulous cave diver and had logged more than60 hours on rebreathers. He was, however, a recently diagnoseddiabetic and did not have a blood glucose test kit in thecave.

-submitted by Rob Parker & BillStone


MAR94-A very experienced technical diver, PADIand NAUI instructor and ANDI nitrox instructor trainer, mistakenlybreathed his EAN 50 (50% O2, balance nitrogen) decompression mixduring a wreck dive to 50 m/164 f (PO2 = 3.0) on the Coolooli, andconvulsed and drowned 18 minutes into the dive. Efforts toresuscitate the 47-year-old diver were unsuccessful. The diver wasdiving air supplemented with EAN 50 mix for decompression-a commonpractice among Sydney wreck divers. Reportedly, the diver carriedboth his bottom and decompression mix on his back and ran boththrough a switchable manifold block. Several colleagues apparentlytalked about the shortcomings of this configuration with the diverwithout success. An analysis of the contents of the tanks showed thatthe diver breathed EAN50 during the duration of the dive. Heconvulsed just as he and his tow dive partners began theirascent.


94APR-Three "untrained" open water divers ranout of gas and drowned in the Big Boil Blue Hole cave system. None ofthe divers were cavern or cave certified.

It was reported that the three divers enteredthe low and silty Big Boil cave with only two guide lines. Two of thedivers carried single 72 cf tanks. The third carried a single 80 cftank.

The team leader who reportedly had "dived BigBoil many times before," made the dive without a depth gauge, BC,knife or redundant second stage. The team apparently made about 150foot/46 meters penetration to a depth of 75 f/23 m.

Two of the bodies were recovered on the mainline at what is believed to have been their point of maximumpenetration. One of the divers was tangled in the line. The body ofthe team leader was located after an extensive search, in arestricted side passage approximately 150 feet/46 meters off the mainline.

-submitted by Al Pertner


94MAY-Two very experienced divers who were notcave certified, got lost in a popular Blue Hole during a live-aboarddive trip, ran out of gas and drowned. Neither diver was running aline or carrying multiple lights.

One of the divers was found within 100 feet/30m of the cavern zone in about 90 f/28 m. The second body wasrecovered by a cave recovery team the next day at about 400 feet/122meters from the cave entrance in about 120 f/37 m of water. Both werewearing single 80 cf tanks. It is not known if the bodies wereseparated by the tidal flow in the system or if the team had beenseparated during the dive.

The cavern zone at the site is often dived byrecreational divers from a liveaboard. A partner of one of thedeceased who was on the dive boat believed that the two "had nointention of making a cave dive," and in fact, had left line reels onthe boat. One of the divers was going shell collecting. The other wasapparently planning to shoot video. The partner believes that the twogot intrigued an ventured out of the cavern zone into the cavesystem. Ironically, the two were considered the most experienceddivers on the liveaboard trip. One of the divers was a formercommercial and military diver, was open circuit mix trained and hadworked as a divemaster with a technical diving operation. The otherwas a dive store owner, a 20 year instructor and was in the processof completing a cave course.

Near TragicMix-Up

On 9JUL my son Jonathan asked if he could scubain our backyard pool. Jon is almost 12 years old and has been usingscuba in the pool for two years. I didn’t really want to butafter relentless asking, I gave in. It was around 7 p.m. so insteadof using his usual 30 cubic foot (cf) pony bottle, I grabbed a yellow14 cf pony for him from the stack. He geared up and we went in thepool.

I sat on the diving board as Jon entered thelow end of the pool. My younger son, Bryon sat on the stairs. Jonwent underwater and after a few minutes something seemed wrong. Iwent to the low end of the pool and Bryon shouted "Something’swrong Dad." Bryon grabbed the skimmer pole and poked Jon who wasfloating face down. He didn’t respond. I jumped in the water andpulled him up. He was blue and not breathing. I got him out of thepool into the deck and started CPR. He had a pulse but was notbreathing. After rescue breathing, for what seemed like eternity, Iwas able to restore his breathing. My wife Jean had called 911 (aUS-wide emergency hotline-ed.) and the rescue personnel arrivedseveral minutes later.

As I was explaining what happened to one of therescue teams, I looked into the pool and saw the yellow 14 cf ponyfloating where Jon had been. Then it struck me like a ton of bricks.When I first started using argon gas for suit inflation, I committeda cardinal sin. I failed to paint the bottle brown or to properlylabel it as containing argon. After obtaining a proper argon bottle,I thought I had drained the 14 cf pony, but I hadn’t. Somehow Ihad it mixed up with my other pony bottles. When Jonathan wentdiving, I had picked up that bottle out of the stack. It was lack ofcaution and it almost cost me my son. Thank goodness, Jonathan hascompletely recovered with no lasting effects.

It is of the utmost importance that all typesof gases be properly marked, that the required types of values andregulators be used, and that different gases be stored independentlyof each other (Note that Compressed Gas Association, CGA, conventionsrequire that special connectors be used for each type of gas to avoidmix-up - ed.). I consider myself a careful and responsible person,however negligence, whether intentional or not, can be deadly in oursport. If writing this letter averts just one tragedy, then thehorror we went through will not be in vain.

-submitted by Bill Delmonico, Scituate,RI

SouthCoast of England

93JUL-An experienced wreck diver failed tosurface following an air dive to 109 fsw/58 msw on the Merchant Royaland is assumed dead. The diver had become separated from her partneron the wreck who surfaced with the minimum required decompression andraised the alarm. Though visibility was excellent the body was neverfound during the ensuing two day search. The diver had been wearingtwin 12 liter independent cylinders (about 200 cf) and a pony withdecompression gas. She dived regularly to these depths and wasreported to be a strong dependable diver.

-submitted by Simon & Polly Tapson, London,England


93AUG-A wreck diver lost consciousness during a15 minute deep air dive to 78 msw/254 fsw on the paddle tug, Koputai,and drowned. The diver lost consciousness while returning to theanchor line after a 15 minute planned bottom time to make his ascent.Though his three partners attempted to ascend with the diver in tow,they were unable to maintain a regulator in his mouth and hesubsequently drowned. The team preceded to lift the unconsciousnessdiver to 15 msw/50 fsw and released him to surface. Surface supportpersonnel initiated EAR and radioed for emergencyassistance/evacuation. The diver did not regain consciousness and waspronounced dead a short time later. Though the Coroner’s reporthas not been released, CNS toxicity (working PO2 = 1.85 atm)compounded by possible CO2 build-up and narcosis-characteristic ofdeep air dives-is suspected as the primary causal factor. Theincident raised government concerns about local deep divingpractices. Though mix training has just gotten started in Australia,most deep dives are still conducted on air.

-Submitted by Richard Taylor, Sydney,Australia.

LittleRiver, Florida USA

93SEP-A novice cave diver ran out of gas anddrowned on a solo dive in the Little River cave system. The diver wasfound with no air in either of his independent 104 tanks about 1300feet back in the cave on the mainline. Though the individualfrequently made solo dives he was not diving with a "buddybottle."

The diver was known to use "creative" gasmanagement rules outside of the basic tenets of cave diving and on atleast one occasion had explained the gas management strategy heutilized to a group of cave students. Basically the diver reservedsufficient gas to exit form known points in the cave using theoutflow in the system. The problem is that liberalized gas managementrules such as this leave not margin for error or the unexpectedcompared to the golden "rule of thirds" or better (i.e. use at least1/3 of your gas for penetration and exit on the remaining twothirds).

Members of the recovery team speculate that thediver ventured into an unfamiliar part of the cave and got lost inthe low silty tunnels and "tees." Having silted out the area, thediver spent precious time searching for the main line connection andlikely missed the tee on the way back. Eventually he found his way tothe line but it was too late. A long time aquaCorps subscriber, hehad renewed his subscription only a week before.

WakullaCounty, Florida USA

93SEP- A very experienced 24 year old, cavediver lost consciousness and drowned while negotiating a restrictionon the way back to the team’s decompression stages following adeep mix exploration push to about 220 fsw/66 msw with a plannedbottom time of 120 minutes.

The inbound leg of the dive which was thelatest in a series of progressive pushes intended to connect severalmajor sinks had gone as scheduled. The team of three reached the endof the line in a good time and added about 800 feet of line (7800feet back at about 220 fsw/66 msw) when the diver "unexpectedly"called the dive. The team turned for home. Upon reaching theirstaging area, the lead diver turned to see the diver tangled in theline struggling with his stage. The third diver freed him and theycontinued although the diver appeared shaken. As the diver negotiatedthe "short cut" restriction at about 200 fsw/ 61 msw and 2000 feetback, then his scooter prop caught and ate the line, halting hisforward motion and pinned him between the floor and the ceiling justas his stage bottle ran out of gas. He flashed an "Out-of-Gas" signalto the lead diver who responded with his long hose. Thinking thediver was out of gas (he actually had 1000 psi in his 104s and 1000psi in his other stage), the lead diver passed him a stage bottle.The diver gave back the long hose and jettisoned his old stage. Atthis point the cave silted up and the lead diver lost visualcontact.

From the rear, the third diver saw his teammate wedged in the restriction and initiated touch contact as thecave silted out. The third diver squeezed his leg to indicate "Go"and the diver kicked. He backed off then squeezed again with noresponse. He tried to pry him free and at some point realized thediver was dead. The third diver unclipped his scooter and stagebottles and was able to squeeze around the unconscious diver in thecloud of silt and made physical contact with the leaddiver.

Silted out and under the time constraints oftheir gas supply the remaining two divers linked up and motored backto the safety of the decompression bottles. The two had about sixhours of decompression remaining.

The incident generated serious discussion inthe cave community regarding the role of a dive team and how muchpush is too much. Reportedly the diver couldn’t sleep the nightbefore, had ill feelings about the dive, and exhibited anxiety. Hetold at least one person that this was the last of these dives hewould do. It was reported that the diver was "off" that day and thathe may have chosen to go ahead so as not to miss the "big" dive andlose status.



93OCT-A novice deep diver lost consciousnessand drowned during a "deep air" wall dive beyond 300 fsw/92 msw. Thediver and his two partners, all experienced recreational instructors,were attending a combination charter and week long seminar on"Advanced Diving," and had been conducting progressively deeper airdives between 200-300 fsw/61-91 msw during the week. Though the boatapparently had a "YOUR ON YOUR OWN" policy, a mix instructor on thecruise made a "deep air" dive with the team to about 250 fsw/77 mswto check them out and give them pointers on their technique. Hereported that based on their skills, he discouraged them fromdiving deeper. The captain was concerned as well. In fact a fourthdiver associated with the team was reportedly asked not to dive deepor his trip would be curtailed.

The divers were utilizing dual independentlyrigged 80 cf cylinders and decompressing on air (oxygen wasapparently not available). The dive was planned for five minutes to300 fsw/92 msw using USN Exceptional Exposure Tables (to 300 fsw)with backup tables to 15 minutes. The diver was carrying a videocamera to film the teams escapades and was the only member of theteam with a decompression tool-a computer-for depths beyond 300 fsw.According to one of the team, the group overstayed their plannedbottom time by a minute or so and then the diver and one partnerbegan to drift further down the wall (beyond 300 fsw). Having emptiedhis first cylinder "unexpectedly" (the divers did not switchregulators during the dive to balance their gas supply) and feelingthat the dive "was starting to go wrong," the shallow member of theteam executed a "rocket ascent" (of 100 fpm or more) that he hadlearned in the course to "get out of the danger zone," and ascendedto his first stop. Apparently moments later, the first diver lostconsciousness somewhere around 325-350 fsw/99-107 msw. His partnerbegan to haul him up using his BCD for added buoyancy when one of hissingle cylinders also ran out of gas. He lost his grip on theunconscious diver while switching regulators and due to buoyancydifferences was separated from the diver. Short on gas he ascendedand survived. The diver’s body was never recovered off the wall.He was survived by his wife and wife and four month oldchild.

PompanoBeach, Florida USA

93OCT-A diver experienced what appeared to bethe first onslaught of a CNS oxygen toxicity hit during an air diveto 228 fsw/70 msw on the RV Johnson, was able to make a rapid ascentto about 105 fsw/32 msw and survived. The diver and two othersdescended towards the wreck in order to set the anchor. Missing thewreck, and being deeper than they had planned, the divers began ahard swim at about 228 fsw/70 msw (PO2 = 1.66 atm) for about fiveminutes out of what was planned to be a 10 minute bottom time. Hereached the mast at 190 fsw and tied off the anchor.

As he was working he got a severe pain in hismolar, his lip began twitching and his jaw started chattering.Feeling a convulsion coming on, he held his regulator in his mouth,tried to signal to his partners and hit his BCD inflator just as hebegan to lose his vision and experience a mild convulsion. Theysymptoms began to clear during the rapid ascent and he was able toregain control about 115-120 fsw/35-37 msw and stopped himself atabout 105 feet/32 meters. The diver was then able to pull himselftogether. He completed his scheduled decompression and included a 20fsw/6 msw oxygen "hedge" stop on EAN 80 (80% O2, balance N2). Hesurfaced without incident. An extenuating factor may have been theprescription decongestant, Entex LA. The drug had been used by thediver at recommended doses during the preceding week of diving. Hehad previously bought a regulator retaining by "forgot" to bring itthat day. According to the Divers Alert network (DAN) there is nodata to link the drug to the incident.

HighSprings, Florida USA

93OCT-An experienced cave diver lostconsciousness at the start of a "pleasure" cave dive at Devil’sEar and drowned. The dive was intended to be a fun dive to practicescooter techniques. The team of two mounted their double stagebottles and scooters and descended into the "Ear" against the normaloutflow. The lead diver went through the first restriction afterexchanging OKs with his partner. The diver appeared preoccupied. Thelead diver got to the "Lips’ about 200 feet into the cave,turned and waited. The diver wasn’t there. Not seeing hislights, he turned and back tracked. He found the diver unconsciouswith his regulator out of his mouth in about 30 to 40 feet of water.The diver was immediately brought to the surface, CPR was initiatedand the diver was flown to Shands Hospital. The diver was placed onlife support but never regained consciousness and was pronounced deadthe following morning. The Coroners report didn’t shed light onthe cause of his trauma. He had not history of heart problems, nopredisposing medical conditions and no signs of embolism. Individualscan only guess that the diver had a serious problem, turned to exitfollowing the floor of the cave, missed the exit, lost consciousnessand drowned.

Oxygen:good, bad, and ugly

an aquaCorps report

Botany Bay, Australia

1993 February-A diver experienced an out-of-gasemergency as a result of equipment failure, lost buoyancy controlduring descent and blew to the surface following a 18 minutes, 207fsw (64 msw) air dive on the SS Woniora, omitting 44 minutes ofdecompression. The surface support team returned the diver to thewater within five minutes for in-water oxygen therapy beginning at 20fsw (6 msw). After completing 30 minutes of oxygen decompression at20 fsw (6 msw), she ascended to 10 fsw (3 msw) where she completed anadditional 30 minutes. She surfaced without apparent symptoms, wasplaced on surface oxygen and evacuated to a hyperbaric center whichwas 30 minutes away.

The diver presented mild neurologicaldecompression illness on admission and was treated on an USN Table 6with two follow up treatments of two hours each at 30 fsw (9 msw) onsubsequent days. She was discharged three days later with no apparentresidual symptoms. Although in-water therapy was not condoned byhyperbaric officials, they stated that the diver probably would havepresented in a far more serious condition had it not been carriedout.

-Submitted by Rob Cason, Fun Dive Centre,Sidney, Australia.


1993 March-A full cave and nitrox instructorsuffered an oxygen convulsion during a deep air dive in a sink a holein Mexico and drowned. His partner who experienced CNS toxicitywarning signs during the dive and a safety diver survived. The twolater recovered the body.

The team had planned a 20 minute air dive inexcess of 230 fsw (71 msw)-the depth of the saltwater halocline-in acavernous open-water sinkhole near Merida on the Yucatan Peninsula.Because of the difficulty in obtaining helium mixes in Mexico, theteam decided to conduct the dive on air followed by oxygen fordecompression. Both were experienced deep divers. A weighted descentline was rigged for navigation and for staging oxygen and extra aircylinders. The safety diver was to descent with the team to 220 fsw,ascend to a shallower depth and wait for the dive team.

After a long slow descent past the halocine,the team tied into the descent line to explore the well at aleisurely pace. Informed sources estimated their maximum depth to beclose to 300 fsw (92 msw) (A PO2 in excess of 2.0 atm-e.d.). Thesurviving partner experienced a tingling in his lower lip and turnedback to call the dive only to see the diver headed back as well. Whenhe reached the line, he sensed that the diver was in trouble. Thediver grabbed the line and began a hurried hand-over-hand ascent. Thepartner reached the diver, gained control and they began to ascendtogether. The diver continued to pull on the line creating slack andgetting himself tangled. His partner cut him free. The diver thendarted got tangled again apparently convulsed. By the time hispartner reached him the diver’s regulator was out of his mouth.At that point they were still deeper tan 230 fsw (71 msw). Afterrepeated attempts to force the regulator back into the diver’smouth with no success, the surviving partner realized the diver "wasgone" and leaving the body entangled in the line, ascended tocomplete his decompression. Following decompression, the partner andsafety diver were able to pull up the line and recover thebody.

PompanoBeach, Florida

1993 March-An experienced 47 year oldspearfisherman apparently switched to his oxygen regulator by mistakewhile chasing down a grouper at about 220 fsw (68 msw) during a deepair dive, convulsed and drowned. He was found on the railing of theRB Johnson with his regulator out of his mouth by his partner, whowas reportedly diving trimix. The body was later recovered by thecharter boat captain.

The diver was wearing twin "independentlyconfigured" 100 cubic feet cylinders, and an E-cylinder oxygen ponyfor decompression. Using this configuration, a diver must repeatedlyswitch regulators during the dive in order to balance the gassupplies. Though the diver used a distinct oxygen regulator which waslabeled in green, his primary, secondary and oxygen regulators werebanded together and mounted over his right shoulder. It is believedhe mistakenly switched to his oxygen regulator in the heat of thechase (A PO2 of 7-8 atm), having speared his first grouper at 240 fsw(74 msw) earlier in the dive. He convulsed, spitting the regulatorout of his mouth and drowned. Vomit and blood were found in hismask.


1993 May-A deep air diver was reported missingand is presumed dead after he failed to return from an afternoon solodive. The dive had been training for some time in hopes of setting anew record for deep air diving and had spoken about this plans toseveral individuals in the States who tried to dissuade him.According to local observers the diver had made air dives in the470-520 fsw (144-160 msw) range, qualifying him for some kind ofrecord.

The diver was last seen late on a Wednesdayafternoon when he typically made solo dives. Later, friends found hiscar parked near the dive site, Twin Palms, and reported him missingwhen he did not show up by 9:30 p.m. The local dive store apparentlysaid he went out a 4:00 p.m. Search divers were unable to find thebody.

-Excerpted from Compuserve and the "VirginIsland Daily News."

Key West,Florida

1993 May-A diver mistakenly switched to his"labeled and color-coded" oxygen regulator instead of EAN 36 at his90 fsw (28 msw) decompression stop following a 25 minute exposure to210 fsw (64 msw) conducted on trimix 17/50. The diver‘seized’ approximately four minute later at his 70 fsw (21msw) stop during the mix training dive and spit his regulator out ofhis mouth.

A second diver was on the scene in seconds, andunable to reinsert the regulator and having a substantialdecompression obligation, inflated the divers BCD and sent him to thesurface. The diver was picked up immediately by the surface supportcrew and displayed faint irregular breathing. He as cut out of hisequipment, lifted on the boat and placed on oxygen when he becamesemi-conscious. Emergency evacuation procedures were initiated andthe boat left to rendezvous with an ambulance dockside about 50minutes away. The diver regained full consciousness within about 15minutes and did not exhibit DCI symptoms. He was evacuated from thehospital to a chamber within a hour and a half. Still not exhibitingsymptoms he was treated with a Table 6. The diver has little memoryof events following his 90 fsw stop until regaining consciousness atthe surface. Apparently his only warning a ‘vague’ feelingthat something was wrong after switching to O2.

-Reported by Key West Diver Inc.