Review of some of the Accidents

Over the last few decades we have learnt much more about the origins of human failures. The industries/organisations must consider human factors as a distinct element to be assessed and managed effectively in order to control risks. Some of the following accidents of in different sectors (blue in colour) provide clues to understand failures:

Accident, industry and date


Human contribution and other causes

Three Mile Island Nuclear industry 1979 (Nuclear industry)

Serious damage to core of nuclear reactor.

Operators failed to diagnose a stuck open valve due to poor design of control panel, distraction of 100 alarms activating, inadequate operator training. Maintenance

King's Cross Fire Transport sector 1987 1984 (Transport sector)

A fire at this underground station in London killed 31 people.

A discarded cigarette probably set fire to grease and rubbish underneath one of the escalators. Organisational changes had resulted in poor escalator cleaning. The fire took hold because of the wooden escalator, the failure of water fog equipment and inadequate fire and emergency training of staff.

Clapham Junction 1988 (Transport sector)

35 people died and 500 were injured in a triple train crash.

Immediate cause was a signal failure caused by a technician failing to isolate and remove a wire. Contributory causes included degradation of working practices, problems with training, testing quality and communications standards, poor Supervision, lessons not learnt from past incidents. No effective system for monitoring or limiting excessive working hours.

Herald of Free Enterprise 1987 (Transport sector)

This roll-on roll-off ferry sank in shallow water off Zeebrugge killing 189 passengers and crew.

Immediate cause was the failure to close the bow doors before leaving port. No effective reporting system to check the bow doors. Formal inquiry reported that the company was 'infected with the disease of sloppiness'. Commercial pressures and friction between ship and shore management ad led to safety lessons not eing learnt.

Union Carbide Bhopal, 1984 (Chemical Unit)

The plant released a cloud of toxic methyl isocynate. Death toll was 2500 and over one quarter of the city’s population was affected by the gas.

The leak was caused by a discharge of water in to a storage tank. This was the result of a combination of operator error, poor maintenance, failed safety systems and poor safety management.

Space Shuttle Challenger 1986 (Aerospace)

An explosion shortly after lift-off killed all seven astronauts on board.

An O-ring seal on one of the solid rocket boosters split after take-off releasing a jet of ignited fuel. Inadequate response to internal warnings about the faulty seal design. Decision taken to go for launch in very cold temperature despite faulty seal. Decision-making result of conflicting scheduling/safety goals, mindset, and effects of fatigue.

Piper Alpha 1988 (Offshore)

167 workers died in the North Sea after a major explosion and fire on an offshore platform.

Formal inquiry found a number of technical and organisational failures. Maintenance error that eventually led to the leak was the result of inexperience, poor maintenance procedures and poor learning by the organisation. There was a breakdown in communications and the permit to ¬work system at shift changeover and safety procedures were not practiced sufficiently.

Chernobyl 1986 (Nuclear industry)

1000 MW Reactor exploded releasing radioactivity over much of Europe at environmental and human cost.

Causes are much debated but Soviet investigative team admitted 'deliberate, systematic and numerous violations' of safety procedures by operators.

Texaco Refinery, 1994 (Petroleum Industry)

An explosion on the site was followed by a major hydrocarbon fire and a number of secondary fires. There was severe damage to process plant, buildings and storage tanks. 26 people sustained injuries, none serious.

The incident was caused by inflammable hydrocarbon liquid being continuously pumped into a process vessel that had its outlet closed. This was the result of a combination of: an erroneous control system reading of a valve state, modifications which had not been fully assessed, failure to provide operators with the necessary process overviews and attempts to keep the unit running when it should have been shut down.


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