Re: Dual Cave Diving Fatality in Mexico
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An Examination of the Double Fatality at Cenote Calimba,
Sistema Sac Actun 9th December 2004.
Posted on behalf of Author Steve Bogaerts
Introduction:
This article concerns the drowning of two certified cave divers that occurred on December 9th 2004 at Cenote Calimba, a part of the Sac Actun cave system in the state of Quintana Roo, Mexico.
The two victims were diving as part of a larger group of nine divers which also included a guide. The group had all been diving together for a number of days prior to the date on which the accident took place.
Now would seem a good time to examine the dynamics of this accident in the hope that through the lessons learned more tragic fatalities of this nature can be avoided in the future.
The Dive Plan:
On the morning of Tuesday December 9th 2004 the group traveled to Cenote Calimba on the Coba Road in order to make a cave dive. Calimba is a part of Sistema Sac Actun. This area of the cave is small, extremely decorated and very fragile.
The group split into 2 teams; one team of five which included the guide and one team of four. Both teams planned to enter and then exit at Cenote Calimba.
The dive plan called for the first team of five led by the guide to descend and follow the main permanent guideline to its end where they would encounter a "Snap and Gap".
The "Snap & Gap" is a piece of line approximately 20 feet in length attached to the end of the Calimba line that has a carabineer at its other end so that can be used in place of a jump reel to create a continuous guideline from the end of the permanent Calimba line to the Paso De
Largarto permanent guideline. Typically if not in use the "Snap & Gap" line is rolled up and placed
at the end of the Calimba line.
Team One found the "Snap & Gap" already in place connected to the Paso De Largarto line and installed a yellow personal non directional marker (PNDM) cookie labeled #1 on the "Snap and Gap" line as protocol to show any other teams in the cave that this line was being used and to mark theirexit at this intersection.
Two white line arrows on the Paso De Largarto line point downstream towards Cenote Hotul/Grand Cenote and away from Calimba at this intersection.
Team one followed the Paso de Largarto line downstream for 65 feet until the permanent guideline makes a hard right turn. At this point on the line a single white line arrow points downstream towards Cenote Hotul/Grand Cenote and marks a short jump to a permanent guideline on the left that goes to Cenote Box Chen.
Team one installed a jump spool the short distance (approx 6 feet) to connect the two lines.
Two PNDM cookies were installed at this jump. Cookie #2 was placed on the exit side of the intersection created countermanding the permanent line arrow on the Paso De Largarto line, showing both teams intended exit back towards the "Snap and Gap" and the Calimba line.
Cookie #3 was placed on the jump spool line close to the spool end to indicate protocol on exit (On exit if NDPM cookie #3 had been removed the remaining team were to take up the spool).
Team One would then follow the permanent Box Chen guideline for approximately 500 feet and install an additional spool to make a 5 foot jump to the left that closes the gap on the Box Chen circuit line and continue on the circuit in a clockwise direction until reaching Cenote Box Chen.
The second team of four divers was to descend shortly after Team One allowing them a head start to install the reels and PNDM's.
The plan for Team Two was to follow Team One to the Box Chen line using the spools and PNDM's installed by Team One. The plan was that Team Two would bypass the jump installed by Team One on the Box Chen line and continue in an anti clockwise direction following the line towards Cenote Box Chen until they hit thirds.
Apparently Team Two was expected to turn the dive before reaching Cenote Box Chen based on air consumption rates and were expected to be exiting ahead of Team One.
It should be noted that one member of Team Two had a Digital Camera in an underwater housing equipped with strobes and was planning on taking photographs during the dive.
Team One completed their dive to Cenote Box Chen where they surfaced for approximately two minutes and then returned the way they had come removing the Box Chen circuit spool and the spool connecting the permanent Box Chen line to the Paso de Largarto permanent line together with PNDM cookie's #2 and #1.
The assumption was that Team Two had already exited ahead of them as PNDM cookie #3 was no longer in place.
Team One reached the surface at Calimba after a 99 minute dive having entered the water at approximately 9:00am exiting at 11:10am with a maximum depth of 44 feet.
At no time during the dive had the two teams encountered one another.
Upon reaching the parking area the guide became concerned that Team Two were not there as expected. The guide then drove in one of the group's vehicles the short distance to the Grand Cenote entrance thinking that the lost members of the group may have exited there.
Not finding them at Grand Cenote the guide then returned to Calimba where the two survivors from Team Two surfaced sharing air with approximately 500psi left in one set of doubles.
The survivors informed the guide that the other two team members were still in the cave.
At this point the guide and two of the other members of Team One got back into the water and headed back downstream along the permanent Calimba line to search for the missing divers who were found together approximately 250 feet from the entrance with their second stages out of their mouths facing towards the exit at Calimba.
Both victims had zero pressure in their double aluminum 80 cubic foot tanks. One of the victims primary HID light was still burning. The other victim was at the ceiling of the cave, had his long hose deployed, his primary HID light was turned off and stowed and a back up light was
turned on and lying on the cave floor below him.
One of the three divers recovered the first victim leaving the guide and other diver to recover the second victim which was reportedly difficult due to the small and restrictive nature of the cave passage and the tangled long hose that had been deployed.
A break in the permanent line at this location was subsequently reported a couple of days after the incident by another diver. This most probably occurred during the body recovery with the recovery divers being unaware of it as it was not mentioned by either the survivors or the recovery divers and appears to have no bearing on the accident.
The local authorities took possession of the victim's bodies and equipment upon recovery to the surface and interviewed the guide and all members of the group at the Ministerio Publico in Tulum.
What Happened?
Team Two began their dive at Cenote Calimba shortly after Team One.
They reached the Snap & Gap at the end of the Calimba line in approximately 32 minutes having traveled through very small cave with multiple minor restrictions.
At the Snap and Gap they turned left following the permanent Paso De Largarto line downstream for approximately 65 feet to the jump to the Box Chen line.
They turned left at this intersection and followed the Jump spool line over to the Box Chen line and continued along this line until the dive was called by one of the team members upon reaching thirds.
The team turned around and swam back to the spool closing the 6 foot jump from the Box Chen line to the Paso De Largarto line.
At this intersection the last person in the team removed PNDM cookie #3 but left in place the Jump spool and PNDM cookie #2 marking the exit back to Calimba.
The team of four then all turned left at this intersection rather than right and back to their exit as indicated by PNDM cookie #2.
Team Two then swam following the permanent Paso De Largarto line downstream for a distance of approximately 1,400 feet and 25 minutes. Throughout this time the team member with the camera reportedly continued to take photos.
The team would have swum past four directional arrows all pointing downstream towards Cenote Hotul/Grand Cenote.
At its end the permanent Paso De Largarto line is separated from the permanent Cenote Ho-tul/Grand Cenote traverse line by a distance of approximately 70 feet.
At this point on the end of the Paso De Largarto line the members of Team Two finally realized that they had made a navigational error and were not heading towards their intended exit at Cenote Calimba. One member of the team deployed a safety spool and began a search for the line or exit as indicated by the directional arrow at the end of the permanent Paso De
Largarto line which was pointing towards the permanent guideline to Cenote Hotul/Grand Cenote 70 feet away. The other 3 members of Team Two remained on the Paso de Largarto line
during the search.
The search was unsuccessful and the dive team turned around and swam back up the Paso De Largarto with one member of the team still carrying camera equipment.
It is not known what pressure each of the divers had in their double Aluminum 80 tanks at this point but they were less than 300 feet from the nearest cenote and potential safety.
At some point during the return swim the dive team of four became separated into two buddy pairs. Approximately 100 feet before the 90 degree turn of the Paso De Largarto line where the 6 foot jump to the permanent Box Chen line is located the first pair of divers clipped the Camera system to the permanent guideline.
The Jump spool and PNDM cookie #2 were no longer in place at this time having been removed by Team One as PNDM cookie # 3had been removed previously as they mistakenly believed Team Two had already exited. All members of Team Two continued upstream to the Snap and Gap intersection at the end of the Calimba line. This had been left in place, as it had been found at the start of the dive, but Team One had removed PNDM cookie #1 again in the mistaken belief that Team Two had exited ahead of them.
It is not known exactly how far apart the two buddy teams were at this point however the first team who survived stated that they could see the lights of the divers behind them.
The lead buddy team began sharing air at some point on the Calimba line and
just made it back to the surface with approximately 500psi remaining in one set of doubles.
The victims also apparently began sharing air at some point during the exit but failed to make it all the way back to Cenote Calimba both drowning approximately 250 feet short of the exit with no air left in either set of doubles.
The survivors had a total bottom time of 129 minutes and the victims 141 minutes when they were found giving a difference of only 12 minutes during which they had drowned.
Accident Analysis and Recommendations:
Accident analysis clearly indicates that confusion and disorientation leading to divers becoming lost and unable to find their way back out of the cave during complex dives is the most common direct cause of fatalities amongst trained cave divers in this area of Mexico.
Ultimately the responsibility for navigating the way back out of a cave lies with each individual diver, however a number of common contributory factors seem to come into play in both this latest accident and several of the other fatalities that have occurred in this area involving trained
cave divers.
Diving with a Guide:
People hire a guide for many reasons but probably the two most basic are to facilitate their diving vacation and to increase their feelings of safety and comfort.
The perception of an increased level of safety may in fact be a false one depending on the planning and judgment of the guide and the attitude of the people being guided.
Divers may undertake dives they would never normally attempt themselves just because they are with a guide. This is a very dangerous situation and one that should be guarded against both by the responsible guide and client. The fact that they are being guided may encourage some divers to abrogate some of their responsibilities during the dive to the guide becoming
merely sightseers following the guide around rather than being full, active, participating members of the team, who remain self-sufficient and self-reliant at all times.
This again is a dangerous and unsafe attitude and should be discouraged at all times.
Guides must exercise a professional attitude at all times and bear in mind that they have a duty of care to and responsibility for their clients particularly when planning dives.
The primary considerations for any guide when planning dives should be first and foremost diver safety and cave conservation.
Good judgment should be exercised at all times and plans should err on the side of conservatism.
It is very important that the guide plans all dives taking into account the experience levels and abilities of every person within the group and selects an appropriate dive site and dive plan with this in mind.
As well as the makeup of the group the number of people in the team should be another very important consideration when planning both the dive site and the dive itself.
Dive shops employing guides should ensure that their guides are meeting acceptable standards particularly with regards to Safety, Cave Conservation and Professionalism.
When looking for a guide some questions it may be worth asking include:
* What is the guide's level of Certification?
* How much cave diving experience (how long have they been cave diving and how many cave dives do they have logged) does the guide have?
* How much experience does the guide have in the actual location you will be diving?
* Does the guide reside full time in the area or are they only a visitor?
* What is the maximum number of clients that the guide will take on adive?
* Ask the guide about their guiding philosophy.
In the Calimba accident it would appear that too many people were diving in too small a cave with too complex a dive plan while lacking the degree of awareness, ability and experience required to complete the dive safely.
Diving as part of a large group:
When diving together with a large number of other divers a group dynamic can take over and group members may plan and undertake dives that they would normally never plan themselves either because they do not wish to let other members of the group down by calling dives or because a false sense of security is engendered just because they are part of a large group
and there is a feeling of safety in numbers.
The group dynamic can lead to some in the group becoming "leaders" while others are "followers" an unsafe situation for all concerned.
This situation can be avoided if large groups are broken down into smaller teams and most importantly that each individual team is responsible for all aspects of the planning and execution of their respective dives.
In the Calimba accident the more experienced divers with the better air consumption were all diving with the guide who installed the reels and personal markers for both teams.
The group of lesser ability and experience were to follow behind.
Diving beyond personal level of experience or ability:
We have all heard of the "80 dive expert" the diver who has just enough experience under their belt to become overconfident or complacent. A little bit of knowledge can be a dangerous thing and in the cave environment if you make a mistake you may not get any second chances.
Accident analysis indicates that many fatalities occur to trained cave divers who have logged between roughly 80 and 120 cave dives.
In the Calimba accident one of the victims had 75 logged cave dives and the other 125.
The two survivors both had 300 logged cave dives completed since their certification 32 years previously, an average of less than 10 logged cave dives per year.
Each diver should make an honest assessment of both their own and other team member's current abilities, level of experience and fitness to dive.
If a long time has passed since original training and certification, or if divers have not been actively cave diving for some time, then either retraining or some form of review with a Cave diving Instructor would be highly recommended before re-engaging in Cave diving activities.
Dives must be planned taking into account the least able member of the team.
Group dynamics, peer pressure, ego threat, a false sense of security engendered by being part of a group or diving with a guide are all factors that can lead to divers either individually, or as a group, exceeding their level of experience and ability.
A large group of divers will always have varying degrees of experience and ability.
Utilizing dive sites and conducting dives that cater only to the most experienced within the group is fraught with potential dangers and extremely damaging to the cave environment.
Breaking the group down into smaller teams and planning dives appropriate for each team allows all the divers to dive within their respective comfort zone.
This may also necessitate different teams within a group utilizing different dive sites.
Dive team members using Camera equipment:
Both safety and conservation issues need to be addressed when considering the use of cameras in cave diving.
Cameras are a distraction and reduce awareness not just for the person using the camera but also potentially for other members of the dive team.
With the advent of digital cameras more and more divers are using them while cave diving and they are becoming a common factor in many accidents.
A dive plan requiring complex navigation should not be complicated further by use of a camera which is likely to reduce awareness to dangerous levels.
If a photo/video dive is planned then that should be the primary objective of the dive team and the dive kept as simple as possible.
Cameras should only be taken on a dive under ideal conditions with the full agreement of all members of the dive team on dives well within the comfort level of every one within the team, in an area of the cave that is well known to all team members and where no impact to the cave will be caused.
In the Calimba accident one of the divers who luckily just survived had a camera and was reportedly taking pictures throughout the dive including for much of the time after the navigational error was made.
Apparently one of the victims had been irritated and annoyed by this incessant picture taking on previous dives and had complained about it to his wife who was not a part of the team.
Overly complex dive plans:
The caves of Quintana Roo, Mexico are both extensive and extremely complex in nature.
Typically each cave has multiple entrances and exits, passageways, lines, line markers and intersections.
The potential for confusion and disorientation in this particular environment is extremely high and diving here requires a high degree of awareness.
If you are new to the area or new to cave diving complex dive plans are unnecessary and potentially dangerous.
Build your knowledge and experience of the cave systems gradually and stay within your comfort zone.
A guide should not be used to short cut this process. Nor should a guide conduct dives for their own gratification rather than in the best interests of their clients and the caves.
Lack of awareness:
In the Calimba accident a team of four cave divers all made a navigational error turning left instead of right at an intersection created by installing a jump reel.
This may not have happened had they placed their own reel and personal markers and been forced to reference the intersection independently.
Having made the jump from the Box Chen line onto the Paso De Largarto line had they turned in the correct direction they should have been expecting to find the Calimba Snap & Gap within a very short distance (approx 65 feet).
Instead they swam downstream rather than upstream for approximately 25 minutes and 1,400 feet in distance through a completely different type of passage past at least four line arrows that they would not have referenced on their way into the cave without realizing their mistake.
This indicates an extreme lack of awareness on the part of all the members of the dive team.
Again this may have been compounded by the use of Camera equipment on an already complex dive.
Awareness is critical to survival while cave diving, take it seriously or stay out of the water.
Staying oriented and referencing your exit at all times is the key to enjoyable safe cave diving.
Always be self sufficient and self reliant, navigate and reference as if your life depends upon it, because it does.
Always run a continuous guideline from the open water throughout the dive.
Make sure all intersections are properly referenced by all divers and marked appropriately for your exit.
All teams should run their own reels and place their own personal markers to avoid confusion and to ensure they take the time to properly reference all intersections.
Stay within arms length of the permanent guideline at all times. Swimming off the permanent guidelines is not safe and causes unnecessary damage as impact is spread around the cave rather than confined to a single track.
Never cut corners you may miss T intersections, Jumps or Permanent Line Markers and end up disorientated or on the wrong line.
In addition to proper line protocol, backup navigation, referencing things such as current direction, compass heading, silt trail, bubble trail, passage configuration, depth and time all play a key part in remaining properly oriented at all times.
Inappropriate dive site for the size of the group:
Calimba is an extremely small, decorated and fragile cave.
It is inappropriate for a team of nine divers to dive there from both a safety and conservation point of view.
The overriding tragedy in this accident is the deaths of two people but we should not forget the extensive and irreparable damage caused to the cave during this incident.
Too many times large groups of divers are being herded through all too fragile caves by inexperienced or thoughtless guides.
Many of the dive sites here in Quintana Roo are very large and can easily accommodate a group of nine divers split into teams all diving in the same area at the same time with no negative impact on safety or conservation.
Other sites may only be appropriate for a single team of two divers both from a safety or conservation viewpoint.
Good judgment and an honest appraisal of both your own level of skill and that of the rest of the dive team will protect not only you but also the cave.
Inadequate or inappropriate equipment:
In the Calimba accident having reached the end of the Paso De Largarto line the dive team finally realized they had made a navigational error.
One member of the team deployed a safety spool to search for the line or exit indicated by the arrow pointing towards the permanent guideline to Cenote Hotul/Grand Cenote at the end of the Paso De Largarto line.
At this point the dive team was a very short distance from an exit and potential safety at either Cenote Hotul or Grand Cenote.
The safety spool deployed reportedly did not have enough line on it to reach from the end of the Paso De Largarto line to the line that goes to either Cenote Hotul or Grand Cenote.
This is a distance in a straight line of approx 70 feet.
A safety reel should have a minimum of 140ft of line on it.
Had this search proven successful the likelihood is that all members of the dive team would have survived.
Although not directly responsible for the two fatalities inadequate equipment meant that a potential chance for the whole team to have saved themselves was missed.
Sharing Critical Safety Equipment between Teams:
This practice can lead to confusion with reels, personal markers and other equipment being removed by one team in the mistaken belief that other teams have already exited the cave even when protocols are in place.
This can lead to a potentially life threatening situation.
Exactly this situation occurred in the Calimba accident as Team One removed reels and PNDM's assuming mistakenly that Team Two had already exited the cave ahead of them.
This does not seem to have played a direct role in the accident but more by good luck than anything else.
It could have easily caused even more confusion and disorientation for the members of Team Two as they searched for their exit resulting in none of them being able to find their way back out of the cave and four fatalities rather than two.
It is strongly recommended that all teams should be entirely self sufficient and self reliant and place all of their own critical safety equipment.
Recommendations:
The following is a list of my suggested recommendations in light of this and previous accidents that have occurred to trained cave divers while diving in this area:
* Maximum ratio of 4 cave divers for every guide.
* Guides must make an assessment of the abilities and experience level of every person within the team and plan dives accordingly.
* Dives should be planned taking into account the least experienced and capable member of the team.
* Site selection should take into account both the abilities and experience of all team members and the number of divers in the team.
* The guide should conduct a thorough review of emergency procedures including touch contact communication and air sharing procedures utilizing both land drills and in water line circuits as necessary prior to beginning any cave diving.
* Thorough predive checks including s drills should be performed before every dive.
* Dive plans must be clearly understood by all members of the dive team.
* Dive plan sketches and cave maps should be used during briefings to reinforce awareness and referencing and can be copied onto diver's slates.
* Each individual dive team should run their own reels and place their own personal markers.
* Cameras should not be taken unless agreed upon by all members of the team.
* Dives in which cameras are to be used should be kept simple in areas of the cave familiar to all members of the dive team.
* Never blindly follow any one into a cave.
* No matter what your position in a dive team whether you are at the front, the back or in the middle be a leader.
* Always be self sufficient and self reliant and navigate and reference as if your life depended upon it because it does.
* Choose dive buddies and guides carefully.
* Remember anyone can call any dive at any time for any reason.
In conclusion it is my hope that the above will lead to a constructive discussion on the points raised which will hopefully result in better education and more awareness amongst the cave divers enjoying the caves of Quintana Roo and help prevent any recurrence of this type of accident.
Steve Bogaerts
NSSCDS Safety Officer Quintana Roo, Mexico
