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Scuba Accidents and Insights

Learning from our own mistakes and miscalculations is a human trait. But, we can also learn from the misfortunes of others and prevent the repetition of similar scenarios.

The factual reports and genuine case studies in this section highlight the tragedies of recent scuba diving accidents and incidents with critical insights to help change future outcomes.

Diving Incident Database: Case Summaries

The Divers Alert Network (DAN) has been maintaining a comprehensive database of diving incidents since 1989.

To begin with, they limited the collection of factual records to accidents and incidents that involved scuba divers.

Currently, DAN's scuba diving accident and incident reports encompass genuine documentation and chronicles about:

The DAN Annual Diving Reports include a vital collection of published analysis. They release the insights and expert conclusions for the benefit of those involved in the scuba diving community.

Furthermore, the featured commentaries and summaries are expressed by professionals in their field. So, divers of all experience levels can use the information to improve their risk management skills and identify safe scuba diving practices.

Note: The main section contains recent news stories about scuba diving and snorkeling activities from around the world, listed chronologically.

Interrupted Decompression Ends in DCS

Most sport divers have a good chance of avoiding decompression injuries even if they miss a recommended safety stop.

But, surfacing before mandatory decompression stops have been completed means the likelihood of getting bent (decompression sickness) increases "significantly".


A buddy pair was conducting a mandatory 3-metre decompression stop on 100% oxygen. But, before they had fully decompressed, they became separated and one of the divers decided to abort the decompression obligation.

The diver determined that their dive buddy had already surfaced safely. So, they went back in the water to resume the decompression at six metres (20 feet). This is when the diver started to feel "general malaise" and nauseated.


After switching gases to EAN32, and descending to seven metres (23 feet), the diver started feeling better (according to the incident report).

A few minutes later, the diver completed the 100% oxygen decompression at four metres (13 feet) with no notable problems.

Within 12 hours of surfacing...

The diver experienced the classic symptoms of decompression sickness (DCS), including discomfort in the torso, mild chest pain, and paresthesia (abnormal "pins and needles"). The health status worsened and the diver went to a local emergency room.

After contacting the DAN emergency hotline number, they referred the patient to a recompression facility where they prescribed a USN TT6 (with extensions). The treatment was mostly successful, and the diver regained some mobility shortly afterward.

What Did We Learn Here?

Anyone who scuba dives should consider the omission of a decompression obligation as being a "significant risk factor" for decompression sickness - and plan accordingly.

It's fair to say that buddy separation happens. Nonetheless, part of pre dive safety planning should involve the prevention of, and procedures for, lost buddy situations.

In Conclusion

Divers must take all measures to avoid interrupting a mandatory decompression. Barometric change during this stage of the dive can lead to enhanced bubble formation.

Apply any corrections prescribed by the training agency if a decompression obligation is not completed as planned. It's also wise to administer normobaric oxygen and keep the diver under observation for several hours after surfacing.

Pro Tip: Another section outlines the guidelines for decompression stop diving and what can happen after omitted decompression.

Dropped Weight Belt Causes Runaway Ascent


A diver was nearing the end of a dive at a depth of six (6) metres (20 feet). Without any obvious warning, the buckle came loose from the strap and the diver's weight belt fell off.

They exhaled and dumped air from the dry suit without delay. The stricken diver also tried to increase drag by flaring their body.

The dive buddy grabbed the ascending diver to try and slow them down. But, the runaway ascent dragged him up as well.

What happened next?

The pair surfaced and both of them used the BCD power inflators to establish buoyancy. One of the other divers in the group retrieved the lost weight belt and brought it back to the boat.

What Did We Learn Here?

If it happens "unexpectedly", a dropped weight belt can cause a rapid and uncontrolled ascent. But, there are several ways to minimise the severity of the situation.

For example:

  • In general, it's best not to put all the weights on a belt. So, you could put small diving weights in the rear pockets of a buoyancy control device (BCD) to spread out the total weights carried. This method also provides options to only drop a "proportion" of the weights in an emergency.
  • Likewise, using a BCD with an integrated weight system means you can share the weights into rear pouches that can't drop off. Other weights could go on the weight belt or be strapped to the tank.
  • Many drysuit divers use weight harness systems. This is another technique used to distribute the required number of weights around more than one location.

In Conclusion

The general rule of thumb in the diving community is to avoid putting too much solid lead on a single belt. Doing so can increase the tension on the buckle and make it more susceptible to open by itself.

Nonetheless, the diver attempted to spread out their body to increase drag and slow down the ascent. This is the recommended course of action to take and is likely to have prevented the incident from becoming a more severe one.

Pro Tip: Remember, the golden rule of scuba diving is to "Never hold your breath"! Rapid and uncontrolled ascents are a common reason why divers get arterial gas embolism (AGE).

Safety Tips if Lightning Strikes the Dive Site

According to statistics disclosed by the CDC, around 28 people die each year from lightning strikes in the United States. Furthermore, outdoor leisure activities account for 60% of lightning deaths.

Here's an abridged account of what happened when some scuba divers got caught in a bad thunderstorm.


A group of experienced commercial divers were working underwater laying lines in a river. An unexpected flash of lightning struck the dive site while they were around six (6) metres underwater.

The divers experienced a discharge of electricity run through their limbs as they were holding some kind of conductive metal material.

Incident Report

The report stated that lightning struck the actual dive site during the line laying operation. The divers were anchoring the line with a salvage lift bag and heavy metal disk brakes. They got hit with several electrical discharges.

They knew there would be a strong potential for scuba diving injuries. So, the divers stopped all activities and surfaced.

Here's the important part:

After contacting the Divers Alert Network (DAN) for professional guidance about lightning strike protocols when diving, they received a physical evaluation from a nearby medical center.

The hospital later released the divers and there were no 'significant' injuries reported. In fact, an official assessment from a doctor stated they received no immediate adverse effects even after being struck by lightning underwater.

Insights and Review

It's fair to say that conducting scuba work during adverse weather should be avoided at all costs. It's also paramount to be familiar with the local weather patterns as part of any dive planning schedules.

Plus, lightning can strike several miles away from the epicentre of a storm. In fact, records show that so-called "bolts out of the blue" can strike surface water up to fifteen (15) miles from dark storm clouds.

There's more...

For the most part, an electrical charge will dissipate (lose its energy) at depths around nine (9) metres (30 feet) below the surface. However, the conductive materials used by the divers most likely accounted for the electrical discharge running through the limbs.

What Did We Learn Here?

If the weather looks the slightest bit inclement, you should avoid going scuba diving altogether. So, what if you get caught in the middle of a lightning storm while you're underwater?

  1. End the dive, exit the water without delay, and seek safe shelter.
  2. If you can't swim to the surface in a safe manner, you should seek shelter around ten (10) metres out of any strong currents. Do not hold on to any metal objects (e.g. submerged metal shipwrecks).
  3. Exit the water following all scuba safety guidelines after the storm has passed.

Pro Tip: If you find yourself scuba diving in a thunderstorm, it is recommended that you seek a medical evaluation after exiting the water.

Shark Bites Spearfisher in Shallow Water

Many of the recent scuba diving accidents share a common theme, such as low air, rapid ascent, or faulty equipment.

But, this particular underwater incident involves a freediving spear fisherman in a relatively shallow depth of water, and a blood-thirsty shark.


The victim was spearing for fish in a body of water that was no deeper than eight metres (35 feet). He got lucky and started to reel in his catch while he was at the surface.

Then, his luck changed when he was bitten on the shoulder by a shark. After being assisted onto the boat, the crew transferred him to a local hospital for a medical evaluation and treatment.

Incident Reported to DAN

The official account of a freediving accident suggests the spear fisherman was kicking and splashing water at the surface after hooking into the fish.

Despite making a 360 degree rotation to check for any danger, a shark came from behind and took a bite out of his shoulder.

Here's the thing:

The incident report states the shark released its grip after the free diver struck it with some considerable force.

Once onboard, they applied a Combat Gauze® to reduce arterial bleeding during evacuation. The location of the bite site meant they were unable to apply a tourniquet.

Expert's Review

It's fair to say splashing and kicking water near the surface would have alerted any large marine predators in the vicinity.

Plus, delaying the removal of a speared fish from the water increases the risks associated with spearfishing near sharks. Large marine predators will respond to significant fish vibrations and bleeding animals in the water.

After shooting a fish, the recommendation is to get help (e.g. from a buddy or boat crew) scanning for any large predators. This could be why the shark was able to attack unsighted from behind.

What Did We Learn Here?

According to the scuba diving fatality rate, free diving accidents are not common. Nonetheless, the use of spearfishing equipment increases the risk of attacks by some marine animals.

Even though water splashing behaviour mimics injured prey, sharks are "not" the most dangerous animals for humans - not even close!

This is the important part:

Anyone who is free diving with sharks should dive with a buddy. In addition, you should avoid spearfishing in water that has poor visibility. Try not to use a belt stringer or dive bag to carry dead or injured fish.

What if you do use a belt stringer? If so, experts recommend cutting the gills or pith the brain of the fish to stop it vibrating. Sharks tend to sense vibrations faster than tiny droplets of blood.

Sometimes, administering a blunt blow to a shark's head or nose can repel its advances. These sensitive areas contain a high accumulation of sensory nerve fibres.

Unless you have training - or some previous experience - experts do not recommend using weapons to try and kill a shark, such as knives, bang sticks, or the actual harpoon.

Pro Tip: If you're wondering... 'what is freediving' we have another section with essential information for beginners.

A Rapid Ascent to the Surface

Have you ever experienced a runaway ascent? This diver did from around eighteen metres (60 feet). Even though she "kept her cool", things could have been much worse.


A sharp rap on the power inflator (low pressure hose) seemed to dislodge something that had caused the valve to stick open. Then, it got stuck again and the diver started another rapid uncontrolled ascent to the surface.

She tried to get the attention of the divers below by rapping on the inflator hose and banging on the scuba tank at the same time.

How to Handle a Rapid Ascent to the Surface?It got worse.

The buoyancy control jacket (BCD) filled with air and started to crush the diver's chest.

The jacket became tighter and the regulator was bringing in seawater. The classic symptoms of inhaling salt water can be dangerous for a diver.

She reached for the secondary regulator from her buddy and took in a breath. It's easy to forget in a moment of panic but she didn't purge it - which resulted in even more choking and coughing.

Her buddy knew they were near the anchor line of the dive boat. So, he helped the stricken diver make a controlled ascent by raising both inflator hoses to let the air out.

In fact, the female diver was unconscious for most of the ascent. But, thanks to the calm actions of the dive buddy, both divers made it safely back to the boat.

What Did We Learn Here?

She was treated for typical shock symptoms (rapid, weak pulse and confusion), and she received emergency oxygen on the dive boat.

After being released from a hospital a few days later, it seems that the diver's panic-induced ascent caused a condition called 'cardiac demand ischemia'.

Simply put, she suffered a heart attack underwater, but there were no signs of decompression sickness for either of the two divers.

Important lessons learned:

  • Always stay close to your dive buddy (close enough to reach using a single breath is good).
  • Practice performing air-sharing techniques at regular intervals.
  • Purge your buddy's alternate air source (octopus) before you use it.
  • You can also prepare for scuba diving emergencies by removing a simulated 'stuck power inflator' and still make your way to the surface.

Pro Tip: Even though recreational scuba has a 'relatively' low serious incident rate, divers who carry DAN dive accident insurance tend to breathe a little bit more "relaxed" underwater.

Buford Sink Cave Diving Disaster

Buford Springs Cave is a popular diving destination. But, local authorities had to investigate the deaths of two divers at the Chassahowitzka Wildlife Park, in Florida (around one hour north of Tampa).


  • Two divers, thought to be in their late 50s, went diving inside the cavern using open circuit SCUBA (with 53 and 72 feet3 aluminium tanks).
  • They conducted two (2) dives in an overhead environment. One of the divers had already died when he surfaced during the second dive. The authorities found the second diver later near the permanent cave line at a depth of forty two (42) metres (137 feet).
  • The investigation confirmed that none of the divers had any gas remaining in their scuba cylinders.

Incident Report Recorded by DAN

As the divers arrived at Buford Sink mid-morning, they chatted with a group of teenage swimmers while they set up the gear.

Dual Scuba Fatalities: Two Divers Died at Buford Sink Cave in Florida.The first onset of a problem arose after they resurfaced from their first dive. That's when the teenagers overheard a discussion taking place between the two dive buddies.

It seemed they were trying to determine whether they had enough gas supply to make a second dive deep inside the cave.

It gets worse:

The report says they also heard diver 'A' express concerns about a possible leak coming from his cylinder.

Nonetheless, the two divers submerged for the second dive around mid-day.

Shortly after, the group saw diver 'B' floating face down on top of the water.

They tried to get him out of the water when they failed to see any bubbles.

It became obvious that diver 'B' was not breathing. So, they notified the local law enforcement and pulled the lifeless body towards the dock. They were unable to completely extricate the diver from the water.

Recovery of the victim, and thorough equipment analysis, took place by the International Underwater Cave Rescue and Recovery (IUCRR).

Equipment Configuration Analysis

When they recovered the bodies of both divers, there was little to no gas in their cylinders. An examination of the SCUBA equipment found it to be functioning in the proper manner.

They found a slight leak on the diving cylinder of diver 'A' (where the yoke first stage regulator connects to the tank valve). A readjustment of the yoke stopped the leak.

Important: Another section explains how inexpensive Vindicator Safety Valve Handles can save lives and how to fit a new replacement assembly yourself.

Cave Diving Review

Scuba diving in overhead environments (e.g. caverns and caves) requires the proper safety equipment and extensive training. The same also applies to depths beyond the standard recreational limit - 40 metres (130 feet). The large cave area at Buford Sink extends beyond 130 feet.

Determining the exact trigger that caused the accident on the second dive is difficult. Even so, planning to explore a site beyond their limits will have increased the likelihood of an unfavourable outcome.

Furthermore, another contributing factor for this fatal accident could have been the failure in confirming the remaining gas reserves prior to making the second dive.

The investigation criticised the use of 53 feet3 and 72 feet3 dive tanks. In this case, they considered them as being too small (compared to the 'industry standard' of 80 feet3 aluminium cylinders).

In fact, Submersible Pressure Gauges (SPGs) read pressure - not volume. Thus, it's possible that the divers did not realise how limited their gas supply was when they started the second dive.

What Did We Learn Here?

There are several recommendations about this tragic dual diver death disaster that new cave divers can use for making improvements.

Important: Being trained in emergency first aid means you're prepared to assist with medical care. Also, some dive operators will insist on you providing a statement for their incident report. DAN also asks for voluntary submissions of scuba accidents and incidents via their Diving Incident Reporting System (DIRS).

Instructor Sentenced after Diver's Death


The incident happened in 2018. A Tec Instructor conducted a rebreather course at Stoney Cove - a large flooded quarry in Leicester.

Even though the instructor had serviced the victim's rebreather unit before he made the dive, the inquest that followed later revealed some 'significant failings'.

The divers descended into a section called 'The Sump'. The maximum depth in this area is 35 metres (115 feet). Yet, course standards for the training conducted dictated a maximum depth of 30 metres (98 feet).

The student received several alarms from the rebreather while the two divers were inside the sump. As a result, the diver should have used the 'bailout' and switched to standard open circuit equipment.

Here's what happened next:

Sadly, the diver became unconscious before he could reach the surface. The instructor and his safety diver attempted to assist the victim, but all 3 divers spent three (3) minutes at the depth of 35 metres.

Upon reaching the surface, the unconscious diver had already drowned...

What Did We Learn Here?

The fatal scuba incident resulted in an investigation by the Health and Safety Executive (HSE) in the United Kingdom.

Findings from the HSE investigation ruled that the Technical diving instructor was responsible for several errors and omissions, including:

  • Inadequately maintaining and checking the breathing apparatus of his student.
  • Failing to stay close enough to monitor his student and his equipment underwater.
  • Contravening TDI rules for exceeding the maximum diving depths for repetitive dives.
  • Failing to have a rescue diver with 'adequate qualifications' accompany the pair (instructor and the student) in the water.

The coroner for Leicester City and South Leicestershire found the failings from the instructor and his safety diver added significant risks to the dive and may have caused, or contributed, to the diver's death.

In February 2023, the instructor was ordered to pay £3,085 costs and undertake fifty (50) hours of unpaid work.

Important: This tragic incident, along with other diving deaths similar to this one, reminds us that there are several key reasons to get dive accident insurance - even though it's not a legal requirement in some countries.

Diver's Mouthpiece Became Detached


A diver went diving for four (4) consecutive days. During the second dive of the fourth day the regulator mouthpiece became completely separated from the second stage of the primary regulator.

Scuba Incident Report

The diver was enjoying a diving liveaboard trip and experiencing near perfect conditions. The water was a balmy 29° Celsius (81 Fahrenheit) and the seas were calm during the four days of island hopping. There was almost no noticeable current.

Scuba Incident: Diver's Mouthpiece Became DetachedThe incident happened as the diver carried out the second dive of the fourth day.

Within ten minutes of being underwater, the mouthpiece became completely detached from the primary regulator (e.g. the plastic component of the second stage).

After a few nervous moments, the diver knew there was a problem as they saw the main part of their primary floating in the water in front of them.

The diver reported swallowing at least three gulps of sea water before switching to their backup regulator (called an octopus).

After taking some recovery breaths they safely ended the dive.

The incident report states that the regulator set was less than two (2) years old. But, it seems the plastic zip tie that holds the mouthpiece in place came loose during one of the previous dives.

Professional Evaluation

In this situation, clear communication with dive buddies is vital. The diver handled the situation with some calmness and they called off the dive without delay to fix the issue.

All divers need to check their equipment before entering the water - including their regulator mouthpieces.

In fact, they could have continued breathing from the open section of the primary (without the plastic or rubber gum shield). But, deploying the scuba octopus backup regulator in scuba emergencies such as this was the better response.

What Did We Learn Here?

First, never underestimate the importance of having your diving equipment serviced prior to the start of a diving season. You can become a PADI® Equipment Specialist and save money by doing it yourself.

In general, the manufacturer's recommended frequency for servicing scuba regulators is once a year (or a set number of dives).

Some divers choose to buy custom mouthpieces for their breathing equipment. If so, it's a simple task to exchange a standard piece for your chosen size and colour.

Beginners tend to bite down too hard and loosen the connection. Thus, you must make sure you secure the mouthpiece in the proper manner - using a strong zip tie.

Finally, dive gear should be streamlined and regulator hoses should be a comfortable length. Remember, if you are wearing scuba accessory add-ons, they can become loose if there is excessive twisting or tugging underwater.

Flushing and Muscle Cramps while Freediving


As per the activities offered on a charter vessel, three free divers took part in one of the introductory level freediving courses.

The group surfaced after completing the first dive to around eight (8) metres (24 feet). Then, one of the free-divers started cramping, feeling flushed, and noticed a sense of extreme fatigue.

Reporting the Incident

One of the group was middle-aged, healthy, and fit. This particular student complained about the problems to the instructor and an assisting diver.

In response, the instructor told the distressed student to rest on a float at the surface while they called for help from the crew on the boat.

Here's the thing:

The captain of the vessel, and a divemaster, helped get the diver onto the boat. They removed the wetsuit, rinsed them with clean water, and provided some drinking water. The two divers went back into the water to work with other students.

When they resurfaced, they found out that the distressed student was receiving emergency oxygen - out of caution. They alerted the emergency services and took the student to a local hospital.

Following a medical investigation, the hospital discharged the diver stating there were no complications or residual symptoms.

Expert Analysis

If your body uses more fluid than taken in, it usually results in dehydration. As a consequence of this, the body does not have enough water to perform its normal functions.

In fact, anyone of any age and any fitness level can become dehydrated. The risk factors increase if you fail to drink enough water during exercise or in a hot climate.

So, what should you do when diving in hot, humid weather? It is important to make sure you are properly hydrated. The situation exacerbates if you are wearing exposure protection (e.g. a drysuit or a wetsuit).

What Did We Learn Here?

To begin with, all scuba divers, snorkelers, and free divers should be familiar with the common symptoms of dehydration. They include:

  • Confusion
  • Dizziness
  • Extreme thirst
  • Fatigue
  • Flushed skin
  • Muscle cramps

Part of dehydration treatment involves consuming clear liquids. The aim is to replenish the lost water. Even so, there can also be a need for serious interventions by medical personnel.

Always seek medical attention if the symptoms worsen. Nonetheless, proper hydration should begin several days before you go diving. It takes longer than you might think for the body to absorb water.

Dive boats in particular should make fresh drinking water and electrolytes available for divers. Plus, divers should also carry their own reusable water bottles so they can increase hydration through the day.

Pro Tip: Another section explains 'what is freediving' and 'how to freedive', including what equipment you will use during the certification courses.

An Underwater Altercation


A fight occurred between a dive guide and another diver while they were underwater. Another dive group saw the event take place while they were conducting a drift dive in deep water.

Diver's Incident Report

It was one of those beautiful days that we often dream about for a scuba dive. The group were undertaking a fun excursion with hopes of seeing a range of different sea-life species, and maybe a shark or two.

After making a normal descent, two groups positioned themselves along the edge of the reef. Following on, the dive guide also found a suitable area to settle and promptly hooked into the reef.

Scuba Incident: An Underwater AltercationAs they looked up, they witnessed one of the divers swim over and, without any clear warning, punch the guide in the face.

After the initial blow, they saw the attacker grab the guide and rip off their mask and regulator.

Unsure of how to handle the situation they had just seen, the buddy pair decided to end the dive and ascend to the surface.

It appears the attacker continued with the underwater altercation and inflated the guide's buoyancy device - resulting in a rapid ascent. The guide responded by grabbing hold of the assailant and they both shot up together.

Here's the thing:

When everyone got back on the boat, no one seemed to have sustained any of the common scuba diving injuries. But, they did manage to establish a motive for the attack.

The dive guide had secured his place on the reef and communicated his intent to the rest of the group. But, the attacker seemed unhappy about it and got too close for comfort. A fight broke out after the dive guide pushed the other diver out of the way.

Expert's Review

Scuba divers fighting underwater is not commonplace, but it happens! The diver who submitted a diving incident report to DAN also stated they were shocked by the severity of the brawl and not sure what they should do.

Often, stress and nervous emotion are the root causes of underwater squabbles. Scuba diving is seen as a non-contact sport, and there is no room for violence in the industry.

Scuba diving accidents and incidents such as this one can easily end up having a fatal outcome. The divers who aborted their dive helped to reduce further escalation and the potential for a panicked response.

What Did We Learn Here?

So, the question you may be asking is what should you do if someone attacks you underwater or you are the victim in a fight?

In simple terms, it is usually better to treat an aggressor as if they were a panicked diver (e.g. diversion tactics in scuba rescue training).

How does that work?

Another section contains more information about diving emergencies and the best tow to use while wearing scuba gear. But, the following steps come from the skills you learn in the PADI® Rescue Diver course:

  1. Whenever possible, use physical force to try and push the attacker away from you.
  2. You may also be able to duck down below them so you can get away from their clutch.
  3. Always face the diver (do not turn your back on them).
  4. Signal for help as soon as possible using devices that make a noise underwater (e.g. a rattle, a tank banger).
  5. End the dive without delay and in a safe manner.

So, what should you do if you are witnessing scuba divers fighting underwater? It's best not to interfere or try to break up the fight.

Most divers carry knives. Even though they may not be carrying the best diving knife available, situations like these can soon escalate.

Instead, wait for the tussle to end and then you may be able to assist any victims. Plus, there may be lost equipment that you can retrieve in case there will be a legal investigation.

Once the confrontation has finished, you should consider whether you (and your buddy) are comfortable to continue with the dive. If not, go ahead and surface in the usual, safe manner. In some cases, it is ethical and prudent to inform the dive operator about any untoward events that you witnessed.

Important: Being trained in emergency first aid means you're prepared to assist with medical care. Also, some dive operators will insist on you providing a statement for their incident report. DAN also asks for voluntary submissions of scuba accidents and incidents via their Diving Incident Reporting System (DIRS).

The Nasty Taste of Caustic Cocktail


This incident involved an assisted diver who was diving with friends and using a closed-circuit rebreather (CCR).

The question is... was poor communication with the boat crew to blame for a regular recreational tech dive to end badly?

Diving Incident Report

The diver is a disabled veteran (who dives with assistance) and has a lot of experience with their CCR unit. But, the new crew on the vessel he was diving on were unfamiliar and untrained for handling this type of specialised equipment.

After explaining their assistance requirements to the crew, the diver completed a pre-dive checklist and pre-breathe obligation.

Here's where things went wrong:

It was clear the hoses were dragging along the boat when the new crew member handed the rebreather to the disabled diver in the water. Even so, he made the final checks and the group started their descent for the dive.

On the way down, at around ten metres, there were some obvious and abnormal breathing issues and they decided to end the dive. The diver who chose to make an incident report to DAN states they inhaled a bad case of caustic cocktail.

After getting back onboard, the symptoms included not being able to talk for half an hour. They also had a burning throat, which lasted for a few days.

Despite not seeking medical attention, the affected diver refrained from any scuba activities for the next six days. They also had their equipment serviced.

Even though it looks like the hose came unattached at some point, it took a deep submersion for the hose to fill with water.

Professional Evaluation

It is important to pack rebreather units with a scrubber material, such as soda lime (a mixture of sodium hydroxide and calcium hydroxide). The scrubber material removes carbon dioxide from the diver's exhaled gas.

But, if a lot of water mixes with the scrubber material it produces a chemical reaction. In turn, this mixture creates concentrated caustic soda, often referred to as 'caustic cocktail'.

Is it dangerous?

Caustic soda can be dangerous if you inhale or ingest it (swallowing it can be fatal). That's why performing pre-dive checklists for rebreathers is an essential task.

There are several ways for water to enter the canister that houses the scrubbing material. But, some of the most common causes will be:

  • Disconnection
  • Failing to close the breathing loop
  • Leakage

Even though the rebreather diver reported carrying out a checklist before the dive, there was no mention about any untoward or abnormal findings in his records.

Nonetheless, calling the dive at the first hint of a problem avoided the need for emergency treatment or a worsening incident.

What Did We Learn Here?

There are several ways to treat the ingestion of caustic soda. You should try to flush it with water as soon as possible. You can use seawater if you don't have access to freshwater.

The primary aim is to reduce the contact time for the caustic soda. So, flushing with freshwater also helps to dilute any residual solution.

Unfortunately, not all crew members who work on dive charters are properly trained on how to handle scuba equipment. Even worse, very few boat staff have appropriate first aid training (e.g. a valid EFR Certification).

Related Information and Help Guides

Important: Divers can report a scuba incident to DAN about a near miss or an event that caused personal injury. Published case reports do not identify any individuals who volunteer their story.

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