Underwater Diving - Hazards of Diving

Hazards of Diving

Divers face specific physical and health risks when they go underwater with scuba or other diving equipment, or use high pressure breathing gas. The hazards can be listed under several categories:

• The aquatic environment
• Use of breathing equipment in an underwater environment
• Exposure to a pressurised environment and pressure changes, which includes:

• Pressure changes during descent
• Pressure changes during ascent
• Breathing gases at high ambient pressure

• The specific diving environment
• Pre-existing physiological and psychological conditions in the diver
• Diver behaviour and competence
• Failure of diving equipment other than breathing apparatus
• Hazards of the dive task and special equipment
• Hazards related to access to and egress from the water.

The presence of a combination of several hazards simultaneously is common in diving, and the effect is generally increased risk to the diver, particularly where the occurrence of an incident due to one hazard triggers other hazards with a resulting cascade of incidents. Many diving fatalities are the result of a cascade of incidents overwheming the diver, who should be able to manage any single reasonably foreseeable incident.

The assessed risk of a dive would generally be considered unacceptable if the diver is not expected to cope with any single reasonably foreseeable incident with a significant probability of occurrence during that dive. Precisely where the line is drawn depends on circumstances. Commercial diving operations tend to be less tolerant of risk than recreational, particularly technical divers, who are less constrained by occupational health and safety legislation.

According to a North American 1972 analysis of calendar year 1970 data, diving was, based on man hours, 96 times more dangerous than driving an automobile. According to a 2000 Japanese study, every hour of recreational diving is 36 to 62 times riskier than automobile driving.

Consequences of diving hazards range from merely annoying through to rapidly fatal, and are listed in the article on Diving hazards and precautions and discussed in detail in other articles linked from that article.