Piper Alpha exploded and collapsed under the effect of sustained gas jet fires in the night between 6 and 7 July 1988, killing 165 of the men on board (30 of whose bodies were never recovered), as well as a further two rescuers.

[14] Four companies (Occidental Petroleum (UK) Ltd, Getty Oil International (England) Ltd, Allied Chemical (Great Britain) Ltd, and Thomson Scottish Associates Ltd) formed a joint venture[a] and obtained an oil-exploration licence in 1972.

[29] Piper's hydrocarbon facilities and principal utilities were distributed in four main modules (A, B, C, and D) separated by firewalls and sitting atop the steel jacket.

[23] In 1978, major works were carried out to enable the platform to meet British government gas-conservation requirements, and to avoid waste from the flaring of excess gas.

[35] Despite the complex and demanding work schedule, Occidental made the decision to continue operating the platform in phase-1 mode throughout this period and not to shut it down, as had been originally planned.

A recommendation from an earlier audit had suggested that a procedure be developed to keep the pumps in automatic mode if divers were not working in the vicinity of the intakes, as was the practice on the Claymore platform, but this was never implemented.

[40] At 22:20, in a case of domino effect,[61] the heat from the burning oil collecting on the diving platform caused the nearby Tartan pipeline to rupture violently.

This could result in a high pressure gas fire on the cellar deck that would be virtually impossible to fight, and the protection systems would not be effective in providing the cooling needed for the duration of the depressurisation".

[63] Personnel still left alive were either desperately sheltering in the scorched, smoke-filled accommodation block or leaping from the various deck levels, including the helideck, 175 ft (53 m) into the North Sea.

[79] A mayday launched by Lowland Cavalier at 22:01 was relayed to a rescue coordination centre, which instructed RAF Kinloss station to scramble a Hawker Siddeley Nimrod maritime patrol aircraft.

[90] Of the 135 deceased whose bodies were recovered, the vast majority died from inhalation of smoke and gas, with only four indicating death from burning, and several others from injury sustained from jumping into the sea.

[94] The largest number of survivors (37 out of 61) were recovered by MV Silver Pit or her fast rescue boat,[88] whose coxswain James Clark later received the George Medal, as did Iain Letham of the Sandhaven.

[40][98] It was estimated that the fires had produced flames with a height of about 200 metres and a peak rate of about 100 gigawatts, or three times the total power consumption of the United Kingdom.

[87] The fires were eventually extinguished by a team onboard Tharos led by firefighter Red Adair,[99] who had been asked to intervene by Occidental chairman Armand Hammer.

They were transported to Flotta, where they were searched by a team led by twenty officers of Grampian Police and including divers as well as Occidental, Department of Energy and Health and Safety Executive personnel.

[3][23] The inquiry decided against the recovery of the process modules from the seabed, due to the time required, the hazards involved, and the low chance that that evidence could actually prove useful for the investigation.

The inquiry was critical of Piper Alpha's operator, Occidental, which was found guilty of having inadequate maintenance and safety procedures, but no criminal charges were ever brought against the company.

[113] Later, Lloyd's and Elf Enterprise Caledonia Ltd, successors to Occidental Petroleum, brought civil proceedings against a number of contractor companies who were working on Piper at the time of the accident.

[115] Giving verdict in what was then the longest civil trial in Scottish history, in 1997 Lord Caplan ruled that two workers who were killed in the explosion, Robert Vernon (who had posthumously received the Queen's Commendation for Bravery)[2] and Terence Sutton, were to blame for the accident.

[114][116][117] Lord Caplan found that Sutton had failed to tighten the bolts of the blind flange at the suction side of the removed PSV, and that Vernon had put the pump back in operation without checking its status first.

[122][123] A lasting effect of the Piper Alpha disaster was the establishment of the Offshore Industry Liaison Committee, the trade union for oil and gas rig workers.

[128] Beginning in 1998, one month after the 10th anniversary, professor David Alexander, director of the Aberdeen Centre for Trauma Research at Robert Gordon University carried out a study into the long-term psychological and social effects of Piper Alpha.

"[4] In 2013, on the 25th anniversary of the tragedy, trade association Oil and Gas UK organized a three-day conference in Aberdeen to reflect on lessons learned from Piper Alpha and industry safety issues in general.

[9] The safety case regime has been ascribed a measure of success in promoting safer facility design and management of offshore operations in the United Kingdom.

[9][142][143][144] Trade association Oil and Gas UK linked a significant fall in lost time injury frequency rate observed since 1997 to the introduction of the regime.

[148] The safety case regime has been adopted outside the United Kingdom, both as a regulatory instrument (for example in Australia,[149][150] Malaysia,[151] and Norway,[149] among others) and as a voluntary initiative taken by several oil companies.

[152] In the United States, the American Petroleum Institute's Recommended Practice 75 for Development of a Safety and Environmental Management Program for Outer Continental Shelf (OCS) Operations and Facilities was issued, at least in part, in response to the tragedy.

[157] One effect of these studies was that a rectangular (rather than square) layout became common for new North Sea platforms, to allow for increased spacing between vulnerable areas and major hazard modules.

[9] In the same spirit, companies also sought to decrease the number of operators needed to run offshore facilities, in an attempt to reduce human exposure to major accidents.

It was sponsored by a number of companies working in the North Sea offshore oil and gas industry, including majors such as Shell, whose Brent platforms substituted for the four train station squares.