The hose broke because it was subjected to a pressure higher than its design limit. That was caused in turn by the closure of a valve in the tanker’s loading system following a leak in a hydraulic line. The spill was spotted once it became sufficiently light to observe the oil in the water. Crude had then been pumped directly to the sea for 45 minutes. Waves with a significant height above 5.5 metres and a wind strength of 45 knots made it impossible to collect the oil or to disperse it with chemicals.
Paradoxically, however, the bad weather prevented the accident developing into an environmental disaster along the Norwegian coast. This was because it caused the oil to disperse under its own momentum. Afterwards, no damage could be found to the maritime environment as a result of the spill.
Poor allocation of responsibilities, deficient understanding of risk, and shortcomings in the loading system design were among the underlying causes. These emerged from the investigation conducted by the Petroleum Safety Authority Norway (PSA), the Norwegian Pollution Control Authority (SFT) and the Norwegian Coastal Administration. Barriers which could have prevented the incident had been weakened over a long period without the management taking the necessary countermeasures.
Although operator StatoilHydro had sufficient information after receiving a report about oil on the sea, the emergency response organisation on Statfjord A was not mobilised. Its response on land was also slow to get off the ground because of inadequate comprehension of the risk posed by the circumstances.
The investigation report identified a number of organisational aspects as well as technical and operational factors as underlying causes of the incident.
- Inadequate mobilisation of emergency response. The PSA took the view that this indicated a lack of comprehension of the risk.
- Inadequate organisation and description of responsibilities. Responsibility for the loading system had been inadequate for a long time, which meant that an overall assessment of the loading system had not been conducted.
- Inadequate risk understanding and robustness. Changes had been made to the loading system without analysing the risk to its overall function. The technical system and specialist responsibility in StatoilHydro’s organisation had been unclarified for long periods.
- Inadequate compliance with the maintenance programme. Deficient maintenance management meant, for example, that the replacement programme had not been followed up and that damage caused by wear and tear on the hydraulic hose had not been identified.
- Inadequate follow-up after a similar incident with the Elisabeth Knutsen shuttle tanker on Gullfaks in 2004.
The public prosecutor for Rogaland county fined Statoil ASA (as the company had by then been renamed) NOK 25 million after the spill. This was accepted by the company. Paradoxically, the news of the oil spill prompted the price of North Sea crude to rise. The market feared that production would be affected.
Granskningsrapport. Oljeutslipp Statfjord OLS-A 12.12.2007. Petroleumstilsynet, Statens forurensningstilsyn og Kystverket.