Worst diving accident in history

A small mistake in operating equipment caused a group of divers working on a North Sea rig in 1983 to suffer an extremely painful death.

Deep-sea diving is a risky activity, not least because of the risk of decompression sickness. To minimize the risk, divers must ascend slowly at the end of an expedition. On oil rigs, where equipment needs to be checked and adjusted frequently, this can slow operations. To combat this, divers are sometimes placed in saturation chambers . These are specially designed chambers with bedding, supplies, and other living items, pressurized to the same pressure as the underwater area where the diver works.

The scene of the explosion at the Byford Dolphin rig. (Photo: StarPulse).

According to the National Oceanic and Atmospheric Administration (NOAA), during a saturation dive , a diver remains in water deep enough to allow all of the body's tissues to equalize with the pressure of the compressed air in the tank. Most recreational and scientific diving requires divers to undergo hours of decompression before returning to the surface after each dive. Saturation diving saves time by keeping the diver under high pressure the entire time. The saturation chamber is filled with a mixture of oxygen and helium to prevent nitrogen buildup in the blood, with the side effect of forcing the diver inside the saturation chamber to speak loudly.

The worst accident in the history of diving occurred in the North Sea in 1983. On 5 November 1983, at the Byford Dolphin rig off the coast of Norway, a diving bell was pulled from the ocean and attached to a saturation chamber. The saturation chamber consisted of chamber 1 containing Edwin Coward and Roy Lucas and chamber 2 containing Bjørn Bergersen and Truls Hellevik, divers who had just returned from a shift. The diving bell was connected to chamber 1, which was operated by two maintenance men, William Crammond and Martin Saunders.

The pressure in these areas must always be kept at a balanced level to ensure that the diving bell can be separated easily. The maintenance staff in charge of this must follow a strict 5-step process including: closing the diving bell door, increasing the pressure in the diving bell to seal the door, closing the door between chamber 1 and the connecting chamber, depressurizing the connecting chamber, and finally opening the lock to separate the diving bell.

However, while the hatches were closing, Crammond suddenly unlocked the diving bell. The entire docking chamber was suddenly exposed to the normal environment, resulting in a pressure difference that caused the system to explode. All four divers faced an explosion beyond what their bodies could withstand, killing them instantly, their bodies torn apart. The air from the docking chamber also pushed the diving bell out, hitting two maintenance men, killing one and seriously injuring the other.

The sudden pressure difference caused the blood of three of the four divers to boil and evaporate. For the fourth, the pressure caused his body to explode, sending his internal organs flying dozens of meters. An autopsy showed that the organs were still intact.

The fatal accident led to the formation of the North Sea Divers Union . Although the investigation report concluded that the accident was caused by human error, the Union decided to file a lawsuit against the rig for not having adequate safety equipment. After 26 years of litigation, investigators determined that the rig had faulty equipment that caused the accident, clearing Crammond of liability. The victims' relatives also received compensation for their losses.