Structural collapse caused the release of around 2,400kg of highly flammable liquid petroleum gas.
HSE investigation found that long-standing corrosion of the steel tower was not dealt with.
Workers exposed to the risk of serious injury and burns in a major incident.
The refinery has been fined £1 million after a major gas leak following an investigation and subsequent prosecution by the Health & Safety Executive.
On 8 November 2022, a partial collapse of a large steel tower caused the structure to slew and rupture pipework, resulting in the uncontrolled release of liquefied petroleum gas (LPG).
The incident led to the loss of approximately 2,400kg (5,300 pounds) of LPG over a 33-hour period. It took just over 30 minutes for around 400kg (~900 pounds) of the gas to be released following the collapse.
Workers were in the vicinity at the time of the collapse and were exposed to the risk of serious injury from falling debris, as well as the potential for burns had the gas ignited. Fortunately, no injuries were reported.
Emergency measures, including the use of water curtains, were implemented to reduce the spread of the extremely flammable vapor. It took approximately 33 hours to isolate the affected process and safely vent the remaining substances to the flare system.
An investigation by the Health and Safety Executive (HSE) found that the structural collapse was caused by corrosion of the steel tower that had developed over many years. This corrosion was identified as early as 2010, but the company failed to take appropriate action to mitigate the risk.
HSE regulates major hazard industries, including oil refineries, under a range of specialist regulations aimed at preventing major accidents involving dangerous substances. This includes oversight of asset integrity, inspection regimes and the management of risks such as corrosion, which can lead to loss of containment if not properly controlled.
HSE guidance states that dutyholders must ensure the integrity of plant and pipework is maintained and that equipment is kept in a safe condition. This includes identifying and managing risks such as corrosion to prevent loss of containment of hazardous substances. Further information can be found here: Corrosion under insulation of plant and pipework v3
The business pleaded guilty to breaching Section 3(1) of the Health and Safety at Work etc. Act 1974 and was fined £1 million and ordered to pay £12,277 in costs at Southampton Magistrates’ Court on 12 June 2026.