On 6 July 1988, the Piper Alpha oil and gas platform exploded in the North Sea. The disaster killed 167 men and became the deadliest offshore oil and gas accident.

Piper Alpha stood in the UK sector of the North Sea, north-east of Aberdeen. It was operated by Occidental Petroleum and had become a major part of Britain’s offshore oil production. By 1988 it was handling both oil and gas, which made the platform more complex and increased the danger when systems failed.

The disaster began with maintenance work on a condensate pump. A pressure safety valve had been removed from associated pipework, and the opening had been temporarily sealed. The pump should not have been restarted. During the change from day shift to night shift, the information was not passed on clearly enough through the permit system.

Later that evening, the pump was started. Gas escaped from the temporary seal and ignited. The first explosion caused severe damage, including damage to control systems. Fire then spread through the platform. Connected pipelines continued to feed gas and fuel into the emergency, making the disaster harder to control.

Many workers had little chance to escape through normal routes. Some survived by jumping into the sea or being rescued from the water. Sixty-one men survived. The dead included men on the platform and two crewmen from a rescue vessel.

The public inquiry, led by Lord Cullen, examined the sequence of events and the wider safety system. Its report found serious weaknesses in maintenance control, permits, emergency planning and management responsibility. It made 106 recommendations.

Piper Alpha changed offshore safety regulation in the United Kingdom. Responsibility for offshore safety moved to the Health and Safety Executive, and the industry was required to take a more systematic approach to major hazards.