The Flixborough explosion occurred at a chemical plant on 1 June 1974, close to the village of Flixborough, UK.

A temporary pipework modification ruptured at a bellows. Within a minute, about 30 tonnes of cyclohexane leaked from the pipe and formed a vapour cloud 100-200 metres in diameter.

On coming into contact with an ignition source, the cloud exploded, completely destroying the plant.

The Flixborough explosion killed 28 people and seriously injured 36, it caused widespread onsite and offsite damage with neighbouring housing devastated.

This incident led to the development of the UK CIMAH and then COMAH regulations.

A runaway exothermic reaction resulted in overpressure and a bursting disc rupture.

Around I kg of dioxin was released into the atmosphere.

A large area of land was contaminated and thousands of animals were slaughtered.

Hundreds of people suffered from chloracne, an acne-like skin eruption, and many women aborted pregnancy's fearing birth defects as a result of the release.

This incident lead to wide spread European concern relating to the control of these plants which resulted in the Sevesco directive, this was enacted in the UK under the COMAH regulations in 1999.

This incident was caused by water being added to a methyl isocyanate storage tank, causing an exothermic reaction.

The situation was made worse by the fact that many safety systems had either been disabled or not maintained.

40 tonnes of toxic gases were vented.

Thousands of people were killed.

A Liquefied Petroleum Gas (LPG) pipe line between storage spheres failed, leading to LPG release which caught fire.

The flame impinged upon spheres, causing a Boiling Liquid Expanding Vapour Explosion (BLEVE).

This triggered a domino effect as one sphere after another exploded as the flames played on them and overheated them.

Housing had been built very close to the LPG storage site.

550 people were killed.

During a morning shift on the Piper Alpha oil rig, a spare pump was taken out of service for maintenance, but the maintenance crew didn’t actually start working on it. However, they removed a relief valve that was on the discharge pipework of the pump. That left an open flange, which they covered with a thin plate to prevent debris falling into the pipeline. This, however, did not provide the integrity required to contain pressure.

At the end of the day shift, the maintenance foreman handed in the work permit, but failed to confirm to the operators that the relief valve had been removed, because the operators were all busy, so he just left the permit on the desk. In short, there was a breakdown in communications.

On the nightshift, the online pump failed, and the crew, as they were faced with a major disruption to production. They figured that as no maintenance work had been done on the spare pump, they could recommission it, not realising that the relief valve was not in place.

Under pressure, the thin plate failed, and the pump began discharging its contents of highly flammable material into the middle of the production platform, which caught fire. That led to other fires – the so-called ‘spiral to disaster’ - and to other equipment overheating and failing. However, the immediate cause of the incident was a failure in the control of work.

169 people were killed, including two rescuers.

This incident occurred during a plant start-up. In the process of introducing flammable liquid hydrocarbons into a raffinate splitter tower, used for distillation separation, operators lost control of the liquid level. They introduced feed, then established heat, but were fed inaccurate readings of the level, and failed to realise that they hadn’t opened the flow away from the column. In fact, all they were doing was pumping liquid into the distillation column.

This went on for some time, the column continued to fill and eventually overflowed, feeding down to a set of relief valves which discharged into a blow-down drum, which should have separated the liquid and gas and vented the gas into the atmosphere.

The blowdown tower was completely overloaded when the liquid filled it, and the liquid blew out the top like a geyser, forming a pool and spreading liquid and flammable vapours around the immediate area.

The vapours from this liquid subsequently ignited from a vehicle parked close by with the engine left running.

15 people were killed, mainly contractors who had been in a temporary building positioned too close to the unit.

Buncefield terminal imported and exported Gasoline (petrol). A high level shut-off switch, which shuts off feed if a tank is filled too high, had been taken out of service for inspection, but had been incorrectly re-installed, and so was no longer functional. The operators were importing gasoline by pipeline and they lost control of the tank level. They had a faulty level indication, and so didn’t realise that the tank had overfilled. The high level switch didn’t activate to stop the feed, and, in addition, didn’t warn them that the petrol was overflowing. The petrol overflowed the tank, ran down the side, and formed a mist which covered the whole of the site. This went on for some time. The column continued to fill and eventually overflowed, feeding down to a set of relief valves which discharged into a blow-down drum, which should have separated the liquid and gas and vented the gas into the atmosphere.

Eventually it found a source of ignition, and the major explosion and subsequent fire which followed destroyed the terminal. Fortunately, nobody was killed, but only because it was early on a Sunday morning.

The overall cost of the incident was estimated at £1 billion.

This crude oil production platform was operating in the deep sea with a water depth of approximately 1 mile.

In this incident, the operators lost control of the oil well and the oil gushed up to the surface, cascaded over the platform and caught fire.

This led to an explosion and fire, and the sinking of the oil rig. As the rig sank, it damaged the pipework which was used to bring the oil up from the seabed, and crude oil leaked into the sea for nearly 3 months.

It should have been possible to stop such a catastrophic leak through activation of the blow out preventer, which is designed to seal the well at the sea bed.

This failed to operate when it was activated from the platform, and subsequent attempts to activate it using an unmanned submarine at the sea bed also failed. 11 people were killed and extensive damage was done to the environment.

The cost is estimated at $40 billion.