This incident happened in the crude oil distillation unit at the land plant, which is operated by ExxonMobil.
The leak led to the evacuation and shutdown of the refinery.
ExxonMobil has estimated the leak rate at about 10 litres per minute, and the total volume which escaped is put at 4.4 cubic metres.
An investigation team comprising specialists from the PSA is now starting work.
The main objective of the investigation is to identify the causes of the incident and possible lessons to be learnt, and to share this information with the industry.
In conducting its investigation, the PSA will
- carefully review the course of events
- assess the actual and potential consequences of the incident
- identify direct and underlying causes
- apply necessary enforcement powers to correct possible regulatory breaches
- make public its findings
- contribute to experience transfer to and learning by other players in the petroleum sector.
The investigation will be summed up in a report published at psa.no.