Accidental fire or explosion on an offshore oil or gas installation

Impact 5
risk indicator
Impact & Likelihood
Impact key
5 Catastrophic
4 Significant
3 Moderate
2 Limited
1 Minor
Likelihood key
5 >25%
4 5-25%
3 1-5%
2 0.2-1%
1 <0.2%


This risk concerns an offshore oil or gas installation. These installations store and process significant volumes of highly flammable hydrocarbon mixtures such as crude oil and natural gas, which could potentially result in a large fire or explosion if released accidently. Operators of these installations have a legal duty to prevent accidents and to mitigate their consequences. The Health and Safety Executive monitors hydrocarbon releases to identify trends and inspects all installations on a regular basis.


The reasonable worst-case scenario for this risk is a fire or explosion occurring on an offshore oil or gas installation. The incident would be local to the site resulting in casualties and fatalities. There could also be environmental damage. The incident may cause supply issues depending on the type of installation, but it is likely there would be sufficient resilience in the supply chain.

Key assumptions

It is assumed that the incident is accidental. The main platform on the installation would be significantly damaged but avoid total collapse. Drilling and key machinery would be closed down quickly, with impacts extending to the people on the platform at the time of the incident.


The impacts of the scenario will vary depending on the size of the fire or explosion, its effect on the integrity of the installation and the size of any resulting substance release. Although the degree of emergency response may differ, the capabilities required of responders are unlikely to change.

Response capability requirements

The capabilities required to manage and respond to an incident would largely be the responsibility of the installation operator. Their onshore command team would need to cooperate with local police, coastguard and the NHS to rescue and evacuate offshore personnel. Firefighting would be carried out by a trained firefighting team with equipment available on the platforms where necessary to assist safe evacuation. Evacuation of the platform and the speed with which this can be accomplished would depend upon weather conditions. The ability to recover, store and identify fatalities and to treat casualties would be required, and operators would need to deliver environmental emergency response plans.


There may be some longer-term health impacts for some casualties arising from the incident. Psychological support may need to be made available to those affected. Environmental damage and the associated clean-up operations could be long lasting. Harsh marine weather conditions are more likely to facilitate the break-up of any potential contamination; however, this would also increase the costs of clean-up due to the need to hire suitable equipment and specially trained personnel. Work to decommission, make safe and dismantle a rig damaged beyond repair could take up to 3 years.