Diver’s accident due to foreign object aspiration

Introduction

In the autumn of 2014, a serious diving accident occurred involving one of four divers. Although the group was swimming together, the first two divers distanced themselves from the second pair during the dive, with the fourth diver lagging behind. The third diver initiated an emergency ascent, during which they unexpectedly descended to the bottom and remained motionless. Shortly thereafter, the last diver found them, brought them to the surface, and performed emergency resuscitation. Subsequent medical examination revealed a foreign object (referred to as a “nut”) in the casualty’s lungs, likely originating from the diving regulator. Fortunately, the accident did not result in a fatality; the diver survived. Nevertheless, the incident merits attention as a reminder of the importance of full cooperation within buddy teams and the necessity of maintaining equipment in a faultless condition.

1       The Diver’s Accident

The incident occurred in November 2014 at the well-known flooded slate quarry Šífr in Svobodné Heřmanice, Bruntál district, in the Moravian-Silesian region. The quarry’s maximum depth is reported to be 35 metres. The events took place at a depth of approximately 20 metres. According to participants, visibility that day ranged between 10 and 15 metres, and the water temperature was approximately 9°C.

Four divers participated in the dive. After convening by the water, they discussed the dive plan and the composition of the buddy team. Two divers were to swim as a pair in the front, with the other two following behind. The third position in the group was assigned to the casualty, who was the least experienced member. This lack of experience became evident at a depth of 4 metres, where the casualty struggled to achieve proper buoyancy control, causing them to ascend to the surface twice before descending again. Once they managed to stabilise their buoyancy, the group continued their dive.

Initially, the dive proceeded according to plan. At a depth of 20 metres, the group paused briefly to confirm everything was in order before continuing. Shortly thereafter, the leading pair swam ahead at a faster pace. The casualty unsuccessfully attempted to catch up with them, resulting in their separation from the slowest diver, who remained behind. As a result, the casualty swam alone, positioned between the leading pair and the last diver.

1.1    Course of the Accident

After a while, the last diver observed the casualty making an uncontrolled ascent to the surface. This was attributed to the casualty’s lack of experience and inability to control buoyancy effectively. The last diver then lost sight of the casualty entirely. Attempting to alert the leading pair, the last diver struck a piece of slate against a metal bomb casing before beginning their own ascent. At approximately 5–6 metres above the bottom, they saw the casualty falling backwards (with arms and legs pointing upwards) and landing heavily¹¹ on a sloped bottom, where they rolled further down to the quarry bottom.

The last diver (hereinafter referred to as the rescuer) quickly reached the casualty, who was lying on their side with bulging eyes¹² and was not breathing. The casualty’s jaw was clenched around the regulator¹³, hampering the rescuer from inserting the backup regulator. The rescuer then grasped the casualty’s BCD inflator and ascended to the surface with them.

Profiles of the dives performed by the rescuer (blue curve) and the casualty (red curve) corroborate the rescuer’s statement. The data shows that both divers followed similar dive profiles¹⁴ until the casualty’s abrupt ascent and subsequent fall to the bottom.
The rescuer’s dive started more smoothly than the casualty’s dive, who initially stayed at the surface for almost 2 minutes and then sank to about 4 meters. Subsequently, both divers continued the dive together. The graph shows that the casualty ascends sharply to a depth of 13.7 meters at the dive time of 13:40 and then literally falls to a depth of 23.8 meters, when his fall, already slower, continues to a depth of 25.9 meters, where he stopped. After almost a minute and a half at the bottom (where the rescuer tried to solve the problem), a rapid ascent (the rescuer carrying the victim out) is started at the dive time of 16:20, which ends at the dive time of 16:40 with reaching the surface.

At the surface, the rescuer inflated the casualty’s BCD. Upon attempting to remove the regulator, the casualty’s clenched jaw relaxed, and they began to expel pink foam and vomit. Despite initial resuscitation efforts being unsuccessful, the rescuer dragged the casualty approximately 100 metres to the shore, where resuscitation was resumed more effectively, resulting in the casualty regaining independent breathing. The rescuer then removed the casualty’s equipment.

Shortly thereafter, the casualty stopped breathing again. The rescuer unzipped the casualty’s wetsuit and continued resuscitation until assistance arrived from the first pair of divers, who helped revive the casualty and called for emergency medical services. A helicopter was dispatched to the scene.

1.2    Witness Statements

Statements from the leading pair of divers provided no significant insights, except for corroborating that the casualty used both diving regulators during the dive¹⁵ and consistently signalled that they were fine.

The rescuer noted that the casualty was wearing a very tight wetsuit, which they believed contributed to the casualty’s breathing difficulties and subsequent cessation of breathing after successful resuscitation on the shore.

Interestingly, the casualty was not interviewed during the investigation, reportedly due to amnesia.

1.3    Consequences of the Accident

The casualty was airlifted to a hospital in Ostrava, where they were examined and briefly observed without requiring extended hospitalisation. The medical report listed the following diagnoses:

• „T 70.3  – Decompression sickness,
• Y 21.99 – Suspected drowning,
• T 17.9   – Aspiration into the lungs,
• J 18.9   – Aspiration pneumonia.“

In the case of the above-mentioned diagnosis of decompression sickness, it is most likely (and taking into account the time and depth of the dive) not a true decompression sickness (DCS type I or type II), but rather a general decompression illness (DCI), which the hospital generally stated in connection with a diving accident. The same applies to the second diagnosis, i.e. suspected drowning. Since it was an underwater accident, the hospital probably preferred to suspect drowning (perhaps also following the information that the casualty was spewing pink foam from his mouth). In the case of „aspiration into the lungs“, the report contained information that during the examination, a foreign object resembling a nut¹⁶ was found in the casualty’s lungs..

2       Findings

2.1    The Casualty

The casualty was a 35-year-old diver holding an Open Water Diver (OWD) qualification, the first level of diving certification. Although they had been diving for nearly five years at the time of the accident, they had completed only about 20 dives. One of the other divers, a diving instructor, assisted the casualty with equipment preparation and assembly before the dive. The instructor also checked the functionality of the equipment and the pressure in the tank.

2.2    Other Participants

All members of the diving group held valid diving certifications. The rescuer and one diver from the leading pair were qualified as Advanced Open Water Divers (AOWD) with 100–170 dives each. The other member of the leading pair was a recreational diving instructor with an Open Water Scuba Instructor (OWSI) qualification. Although the dive was not part of a training course, the group’s varying skill levels and certifications were notable.

2.3    The Casualty’s Equipment

2.3.1 Suit

The casualty used a two-piece semi-dry wetsuit with a thickness of 7 mm. According to other divers, the casualty could not zip up the suit independently, requiring assistance. The rescuer noted that the suit was excessively tight.

2.3.2 Tank and Buoyancy Compensator Device

The tank was a 15-litre steel cylinder, white in colour, manufactured by Faber, and last underwent hydrostatic testing in July 2011. At the start of the dive, the tank was filled to 200 bar, with a residual pressure of 150 bar remaining after the incident. The tank was equipped with a dual-valve system and a plastic boot.

The buoyancy compensator device was a Tigullio T52 jacket.

Neither the tank nor the BDC showed any defects. The volume of the tank and it’s initial gas pressure provided the casualty with sufficient gas¹⁷ to complete the dive.

2.3.3 Diving Computer

The dive logs of the casualty shown in Figure 2 were downloaded from his computer. It was a Vyper decompression computer, manufactured by Suunto. It showed no faults and contained all the necessary data about the dive, including the maximum depth reached of 25.9 m and the dive time of 14 minutes. The logs from the dive computer could be viewed both on the computer itself and downloaded to a PC using a cable.
The data could thus be compared with the data from the rescuer’s computer (who had the same computer model). His computer indicated a maximum depth of 26.5 m and a total dive time of 16 minutes and 40 seconds.

2.3.4 Primary Regulator

The primary regulator system of the casualty consisted of the first stage Xstream DIN 300 bar (manufactured by Poseidon) with a DIN G5/8 thread, to which the second stage Xstream (Poseidon) was connected via a low-pressure hose. The system also included low-pressure hose with a quick-connector to inflator hose of the BCD. Last but not least, a Sopras console was connected to it via a high-pressure hose, on which a submersible pressure gauge (SPG) and compass were integrated. The entire set was in good technical condition, was fully functional and no defects were found.

2.3.5 Secondary Regulator

The secondary regulator used by the casualty consisted of a Cyklon (manufactured by Poseidon) DIN 200 bar first stage with a G5/8 thread. This was one of the earliest models in the Cyklon series, so all ports on the first stage had identical threads¹⁸, and the individual port outputs were marked with following letters:

• HP (High Pressure) – connection intended for a pressure gauge,
• LP (Low Pressure) – connection intended for use with an inflator,
• U (Unisuit¹⁹) – connection intended for connection to a dry suit,
• R (Regulator) – connection intended for a second stage of a regulator.

The second stage, a Cyclon metal (Poseidon), was connected to the first stage (in the port marked „R“) via a low-pressure hose. This is a downstream balanced second stage. Furthermore, there was a Suunto SPG connected to the first stage a high-pressure hose (in the port marked HP). The remaining ports from the first stage (marked „LP“ and „U“) were not used and were therefore sealed with non-original, but functional plugs.

The first stage was in satisfactory technical condition and did not show any defects. The sintered bronze filter was undamaged and free of any impurities. The handwheel with a DIN G5/8 thread used to screw the first stage into the valve was not identical to the handwheels with which this old type of regulator was originally equipped. It was very likely installed on the regulator during a later service/repair.

The second stage of this regulator was in a much worse condition, with several defects of varying severity found. These were:

1. Perforation/rupture of the edge of the membrane approximately 5 mm long, which had no effect on the function or safety of the 2nd stage of regulator (it was a minor defect).

2. Deformation (bending) of the pin of the opening lever of the 2nd stage breathing mechanism, to this extent without affecting the function and safety of the 2nd stage, yet complicating its adjustment (minor defect).

3. Perforation/rupture of the inside of the rubber purge button, extending over 2/3 of the circumference. This defect negatively affects the function of the 2nd stage, as after pressing the purge button, the button remains in the pressed position resulting in uncontrolled gas leakage (free flow).

4. Broken part of the brass segment of the 2nd stage of the regulator. Such defect has a significant impact on the function and safety of the regulator, as the lack of support for the opening lever of the breathing mechanism can lead to the breakdown of this mechanism and subsequent inhalation of loose parts and components (a very serious defect).

Despite these issues, the second stage was operational and could have enabled the dive, but it could also have been a possible source of the accident. However, it is uncertain when the segment broke (prior to, during, or after the dive) or when the purge button membrane was damaged.

3       Discussion

The exact cause of the accident cannot be determined with certainty. It is evident, however, that the accident resulted from a combination of factors, both external and internal. The casualty’s lack of experience and inability to manage the crisis—the inhalation of a foreign object—played a crucial role. This foreign object, identified as a „nut,“ was later discovered in the casualty’s lungs.

It is possible that the nut was inhaled before the dive or entered the regulator during the dive. It may have been inhaled early in the dive or as late as the 12th minute, when the shock of inhaling the object could have triggered the uncontrolled ascent. The casualty provided no information on this matter.

The shortage of breathing gas (air) cannot have been a cause of the accident. At the end of the dive, the remaining pressure in the casualty’s cylinder was 150 bar. The amount of gas consumed aligns with the duration and depth of the dive, ruling out any massive, spontaneous air leakage from the regulator during the dive.

What is indisputable is the poor technical condition of the second stage of the secondary regulator, Poseidon Cyklon metal. The severe defects in this regulator posed a significant risk of a diving accident, either by releasing a broken component into the diver’s mouth or allowing another object to enter the regulator and subsequently the diver’s mouth.

It is also clear that at the time of the accident, the casualty was alone. Although diving with three other individuals, two were unaware of their situation, and the third only noticed the uncontrolled ascent from a distance. While the dive plan indicated that all four divers were part of a single buddy team, the group effectively divided into two pairs during the dive, with members switching between pairs. The first pair subsequently distanced themselves from the second. The divers in the first pair had no knowledge of events behind them and either did not hear or did not respond to the rescuer’s efforts to attract their attention by banging a stone against a metal „bomb.“ Effective communication among the divers was completely absent.

The distance between the rescuer and the inexperienced diver—the casualty—was also unsuitable. In poorer visibility, the rescuer might not have observed the casualty’s uncontrolled ascent or subsequent fall to the bottom. By pulling the casualty to the surface and reviving them through resuscitation, the rescuer undoubtedly saved their life. However, had the rescuer been looking elsewhere at the critical moment, the outcome could have been entirely different.

The dive plan lacked appropriate detail. There was no designated leader for the dive, no specific buddy pairs were assigned, and no lead diver was identified within each pair. The group’s dive plan did not accommodate the skills of the least experienced diver, and no emergency procedures were agreed upon for unexpected separation of pairs or within a pair during the dive.

Although this was not a training dive, one of the participants was a diving instructor. They should have insisted on clearly defined buddy teams, dive plans for each buddy team, and agreed-upon procedures for emergencies. Instead, four divers entered the water, effectively unaware of each other’s activities.

4       Conclusion

During a recreational dive, an accident occurred, fortunately with a positive outcome. The least experienced of the four divers began to ascend uncontrollably to the surface and subsequently sank to the bottom. Two of the divers were completely unaware of him, while the third swam to him, brought him to the surface, and successfully resuscitated him there. Later, at the hospital, a foreign object was discovered in the injured person’s lungs.

The accident could have been prevented with appropriate precautions. Primarily, all equipment should be maintained in flawless condition. In particular, regulators should be stored and transported in individual protective cases (commonly known as regulator bags). Equipment inspection and functional testing should be carried out immediately after assembly and before the dive. This inspection should include a visual check of the entire system, several test breaths from each regulator, and a brief press of the purge button²⁰.

Every dive must be preceded by the preparation of a dive plan and a briefing for all participants. The plan should specify the assigned pairs, identify the leader for each pair, outline the communication methods within pairs and with other pairs, and, crucially, include procedures for handling emergencies.

The fundamental rule of diving is: „Plan your dive and dive your plan.“ Nothing in between is acceptable.

References

[1] JAHNS, Jan, Arnošt RŮŽIČKA a Vladimír VRBOVSKÝ. Přístrojové potápění: Odborné texty pro potápěčský výcvik v systému CMAS. Prague: Svaz potápěčů České republiky, 2012.
[2] PIŠKULA, František; ŠTĚTINA, Jiří a PIŠKULA, Michal. Sportovní potápění. Svazarm. Prague: Naše vojsko, 1985. ISBN 2810585.
[3] ŠTĚTINA, Jiří, Vladimír VRBOVSKÝ, Zbyněk HRDINA, Jan JAHNS, Arnošt RŮŽIČKA a Milan NACHTIGAL. Potápění s přístrojem. Prague: Svaz potápěčů České republiky, 1997.
[4] EN 250 Respiratory equipment – Open-circuit self-contained compressed air diving apparatus – Requirements, testing and marking. Prague: Úřad pro technickou normalizaci, metrologii a státní zkušebnictví, 2014. Sorting symbol: 832242.
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[6] EN 14153-2 Recreational diving services – Safety related minimum requirements for the training of recreational scuba divers – Part 2: Level 2 – Autonomous Diver. Prague: Český normalizační institut, 2004. Sorting symbol: 761301.
[7] EN ISO 24801-2 Rekreační potápění – Recreational diving services – Requirements for the training of recreational scuba divers – Part 2: Level 2 – Autonomous diver. Prague: Úřad pro technickou normalizaci, metrologii a státní zkušebnictví, 2014. Sorting symbol: 761301.
[8] Mapy.cz: Šifr, Svobodné Heřmanice, Česko: https://mapy.cz/letecka?q=%C5%A1%C3%ADfr&source=base&id=1715115&ds=2&x=17.6576344&y=49.9439329&z=17.