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Site last updated
21 August, 2004

Critical Incidents

These are events that could cause injury or an accident. They have major implications with regard to whether a person should continue to dive. In general, a critical incident should lead to a decision to immediately stop diving for a period of time and to seek medical advice if appropriate. Examples of critical incidents in diving are:


Rapid or Uncontrolled Ascent

SCUBA DiverRapid decompression during any phase of a dive can cause bubbles to form. This can lead to decompression illness even if no decompression time has been missed. Bubbles persist in the body after the dive and may not cause any immediate problems. Decompression illness, however, may take some hours to cause symptoms. Further diving in this situation can cause unexpected decompression illness. Another dive will make a delayed episode of decompression illness very much worse.

Advice -


Omitted Decompression

Decompression stopOmitted decompression also leads to bubble formation and again this can lead to decompression illness which can take some hours to develop.

Omitted decompression during a dive also predisposes to decompression illness occurring after subsequent dives even if they are trouble free and within the tables.

Advice -

  • Stop diving.

  • Breath 100% oxygen on the surface after the dive.

  • Contact the coastguard to arrange transfer to the most appropriate recompression facility.

  • Do not attempt to complete stops by going back into the water as this has the potential to make things very much worse.


Transient Illness

From time to time divers feel unwell for a short time during or after a dive. These symptoms can be anything from headache or nausea or pain right through to transient loss of consciousness. Symptoms occurring during decompression or after the dive must be assumed to be due to decompression illness even if they rapidly subside.

The symptoms of decompression illness do come and go and further, severe, deterioration can happen after apparent complete resolution of the problem. The transient illness may not be decompression related. Any illness occurring during diving, however, is potentially life threatening.

Advice -

  • Stop diving.

  • Contact the nearest recompression service for advice and to arrange transfer to the most appropriate recompression facility if necessary.

  • Do not dive again until the cause of the problem has been found in discussion with a doctor qualified in diving medicine.


Water Inhalation

It is not uncommon to inhale a little water while either swimming or diving and usually there is no problem. However, if water inhalation is associated with any chest tightness or pain, breathlessness or cough this indicates that lung damage has occurred. Such lung damage takes some time to recover and for a good part of the recovery period the diver will feel well. Diving, however, during the recovery period is extremely hazardous.

Advice -

  • Stop diving.

  • Get medical advice regarding the problem.

  • A chest x-ray at least is required and diving should only be resumed once the lungs have been shown to have fully recovered.