The PSA Norway has concluded its investigation of the LNG leak in Equinor’s Hammerfest LNG plant at Melkøya on 17 June 2018. Several breaches of the regulations have been identified.
The incident
This leak took place during loading of a road tanker at the gas liquefaction facility. According to PSA, the direct cause of the LNG escape was that a valve on the cold flaring line in the road tanker from Barents Naturgass (BNG) had been left in the open position when loading was completed at the plant’s truck filling station.
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The actual consequence of the incident was an LNG escape to the environment. Its volume was about 996 kilograms, with an initial rate of 0.06 kilograms per second. The leak had small environmental impact. The incident did not cause material damage or production shutdown.
Nevertheless, a gas and dispersal analysis presents that the leak from the road tanker could have been ignited. In that case, the road tanker driver could have suffered third-degree burns in the space of two-three seconds.
Probable cause
The investigation indicated that the direct cause of the incident was the failure to close a valve during verification of the liquid level in the road tanker. However, the underlying causes are related to the method used to prevent overloading of the tanker.
Namely, PSA identified two non-conformities, which are:
- Deficient knowledge about and updating of operating documentation;
- Design weaknesses in the system for overloading prevention and deficiencies in ignition source control.
Moreover, three improvement points have also been identified:
- Lack of follow-up of BNG;
- Lack of clarity over who should evacuate in the event of a factory alarm;
- The clock in the emergency response centre showed the wrong time.
The investigation report has been sent to Equinor, which has now to explain how the non-conformities will be dealt. It has also been asked to provide its assessment of the improvement points which have been noticed.
Equinor has until 24 January 2019 to respond.
