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Learning difficulties

Inquiries into three oil spills on the NCS in less than a year found clear similarities between these apparently different incidents. One is the inability of companies to learn from hardearned experience gained by them and others.

A hose linking Statfjord A and its loading buoy ruptured in December 2007 to cause the largest oil spill on the NCS since the Ekofisk Bravo blowout 30 years earlier. About 4 400 tonnes of crude leaked to the sea during the hours of darkness while a shuttle tanker was being loaded on the North Sea field operated StatoilHydro.

A month later, a similar incident occurred during loading on Shell-operated Draugen in the Norwegian Sea. Although relatively modest, the spill shared several features with the earlier event.

And some 150 tonnes of crude were also pumped to the sea from Statfjord A* in May 2008 during modifications to piping systems for the storage cells in the platform’s concrete gravity base. To halt a small internal oil leak which arose during this work, ballast water had to be discharged from the cells without normal treatment.

* The Statfjord A incident in May 2008 was also very serious from a different perspective, involving as it did a major accident potential for the people on board. See the article on page 12, and other articles as well as the PSA’s inquiry report at www.ptil.no.

The PSA asked the Sintef research foundation in 2008 to review these three discharges in order to identify common features.

This study also looked at the 1977 Ekofisk event and a blowout in the Gulf of Mexico in 1979. It transpired that, despite their distance in time and space, all these incidents display general features in common. Accident causes can be divided into two categories –direct and underlying. The latter embraces the technical, organisational or human factors which allow the direct reason to arise.

An accident can occur through the failure of a component or from human error. Once it has happened, identifying its causes is naturally important – primarily to prevent a recurrence. But no incidents are exactly alike. Nobody knows what will happen next time, or what will be the direct cause.

That makes it even more important to identify the underlying factors. Clarifying such relationships and working purposefully to improve can help to get closer to the goal of the lowest possible level of risk for accidents and undesirable incidents. Sintef found a number of common features, comprising key management elements, among the underlying causes of the five events it investigated.

These include roles and responsibilities, managing and transferring expertise, learning from earlier incidents, and risk assessment of equipment and methods. Ignorance about, lack of respect for or failure to comply with the company’s own procedures also proved a common denominator in the incidents.

All these conditions are subject to regulatory requirements, and govern the way the PSA supervises safety management at the companies.

Oil and gas activities in the far north have helped to lift the environmental issue high up the public agenda, which also affects the commitment to avoiding pollution elsewhere on the NCS.

The petroleum regulations apply to the whole NCS, and the PSA believes that requirements for operating safely are adequate. If they are met, environmentally harmful incidents should be avoided.

These rules do not specify solutions, but define the standards to be achieved. To comply with safety requirements, particular natural conditions in the far north could call for different technical solutions from the North Sea, for instance. The guidelines to the regulations refer to norms and standards which companies can use to achieve compliance. But they must still decide whether these are good enough for the activity concerned.

Through analyses and assessments, companies must decide if the level of risk is acceptable. One question to be answered in this context is whether the standards are sufficient. The PSA finds it positive that standards applied in the petroleum industry are to be reviewed in order to determine their suitability for operations in the far north.

This is part of government’s Barents 2020 plan for Norway’s long-term and cross-sector commitment to research and development in far northern waters.

The PSA is involved in several working parties for administrative planning covering the Barents, Norwegian and North Seas. This forms part of its regulatory role in an environmental context – in other words, preventing accidents which could cause pollution.

“Giving weight to the preventive aspect complements measures to reduce the harmful effects of a spill, and runs in no way counter to the latter,” says Finn Carlsen, one of the PSA’s directors of supervisory activities.

“To ensure that everyone pulls in the same direction to conserve the marine environment, it’s important that accident prevention is given priority and included in risk assessments.

“A risk analyses is not meant to calculate a figure to prove that everything’s fine, but to help understand the mechanisms which create hazards so that the measures adopted are effective.”

By Thor Gunnar Dahle