The Byford Dolphin diving bell accident killed five men instantly through explosive decompression in the North Sea – a catastrophic incident caused by human error on the oil rig
In a harrowing account, a catastrophic blunder beneath the waves resulted in what has been described as some of the ‘most gruesome deaths’ ever recorded, killing five of the six men present.
The horrific tragedy occurred on a semi-submersible oil drilling platform where the divers had been deployed to undertake a deep-sea operation. Whilst the rig looked ordinary enough, it became the location of multiple fatal incidents involving its crew throughout its years of service.
One particularly dreadful mishap occurred on the platform in 1983.
The devastating disaster of 1983
The Byford Dolphin, a semi-submersible oil drilling platform, worked throughout the British, Norwegian, and Danish zones of the North Sea, performing seasonal drilling operations for different firms, reports the Express.
In November 1983, a crew consisting of two British and two Norwegian divers – Roy P Lucas, 38, Edwin Arthur Coward, 35, Truls Hellevik, 34, and Bjørn Giaever Bergersen, 29 – alongside dive tenders William Crammond, 32, and Martin Saunders, 30, were positioned on the platform to complete a deep-sea diving operation.
When the tragedy struck, all six men were carrying out their responsibilities underwater, performing standard maintenance work on the rig at a remarkable depth of 295 feet.
To safely execute their assignments, the team were accommodated in specialist compression chambers for their scheduled 28-day deployment to avoid dangerous nitrogen accumulation in their blood.
Within these compartments, the divers inhaled a precisely calibrated mixture of gases, usually oxygen and helium, modified based on how deep they descended.
The crew employed a practice called ‘saturation diving’, allowing them to remain for extended durations at considerable depths beneath the waves.
This approach was used to help the team sidestep decompression sickness, widely referred to as ‘the bends’, upon their return to the surface.
The workers travelled via a specialist transport unit, a diving bell, to move securely between their accommodation and their submerged workstation.
On 5 November 1983, divers Hellevik and Bergersen were completing a 12-hour stint, assisted by dive tenders Saunders and Crammond. They were heading back to their rest area via the diving bell.
For the diving bell to function safely, it was vital that the team verified the transport unit was secured and properly reattached before returning to their heavily pressurised rest chambers.
This protocol was essential to avoid sudden decompression within the body, which could prove fatal.
Upon entry, the divers needed to shut the hatch and regulate the pressure within their rest chamber to form a hermetic seal.
This step would subsequently isolate the chamber and link it to the dive bell, which would slowly depressurise for the divers’ protection.
However, on that fateful day, the pressure within inner crew chambers 1 and 2 – typically maintained at nine atmospheres – dropped catastrophically to just one atmosphere in mere milliseconds.
The disaster unfolded when an external diver committed a critical error, releasing the diving bell’s latch prematurely whilst full depressurisation remained incomplete.
This blunder meant the clamp securing the chambers opened before Hellevik had properly sealed the chamber door. Consequently, the sleeping chamber’s pressure shifted instantaneously from conditions equivalent to 295 feet beneath the waves to ordinary surface air pressure, according to the Mirror.
Coward and Lucas were understood to be recuperating in chamber 2, experiencing nine atmospheres of pressure when catastrophe struck. The violent, explosive expulsion of air from the chamber propelled the diving bell with tremendous force, smashing into Crammond and ending his life immediately.
Three divers positioned inside the sleeping chambers are thought to have died instantly as nitrogen within their bloodstreams transformed into bubbles, essentially causing them to boil internally and obliterating their bodies into innumerable pieces.
Hellevik, positioned closest to the partially secured chamber door, was forcibly drawn through a narrow 60cm opening, causing his internal organs to be expelled from his body.
The post-mortem examination recorded: “The scalp with long, blond hair was present, but the top of the skull and the brain were missing. The soft tissues of the face were found, however, completely separated from the bones.”
His abdominal and thoracic organs had been expelled.
Hellevik’s body was reportedly sent for autopsy in four separate bags collected from various locations around the rig. Each part of his body inside the bags of bone and tissue reportedly displayed some sign of injury.
Saunders, the sole survivor of the catastrophic incident, suffered devastating injuries including collapsed lungs, spinal fractures and a broken neck.
The tragedy was also attributed to engineering deficiencies. The Byford Dolphin oil rig was operating with an obsolete diving system dating back to 1975, which lacked fail-safe hatches, outboard pressure gauges or an interlocking mechanism.
This vital safety feature would have stopped the divers’ sleeping chambers from opening whilst the system remained pressurised. Notwithstanding these deficiencies, the Byford Dolphin oil rig remained operational with modifications and underwent ownership changes until its eventual decommissioning in 2019.
It was subsequently sold for scrapping in the 2020s.
