Brent Spar

Brent Spar, known as Brent "E", was a North Sea oil storage and tanker loading buoy in the Brent oilfield, operated by Shell UK. With the completion of a pipeline connection to the oil terminal at Sullom Voe in Shetland, the storage facility had continued in use, but by 1991, was considered to be of no further value. Brent Spar became an issue of public concern in 1995, when the British government announced its support for Shell's application for its disposal in deep Atlantic waters at North Feni Ridge (approximately 160 mi (250 km) from the west coast of Scotland, at a depth of around 1.6 mi (2.5 km)).

Greenpeace organized a worldwide, high-profile media campaign against this plan occupying Brent Spar for more than three weeks. In the face of public and political opposition in northern Europe (including a widespread boycott of Shell service stations, some physical attacks and an arson attack on a service station in Germany), Shell abandoned its plans to dispose of Brent Spar at sea  — whilst continuing to stand by its claim that this was the safest option, both from an environmental and an industrial health and safety perspective. Greenpeace's own reputation also suffered during the campaign, when it had to acknowledge that its assessment of the oil remaining in Brent Spar's storage tanks had been grossly overestimated. Following Shell's decision to pursue only on-shore disposal options, as favoured by Greenpeace and its supporters, Brent Spar was given temporary moorings in a Norwegian fjord. In January 1998, Shell announced its decision to re-use much of the main structure in the construction of new harbour facilities near Stavanger, Norway.

Brent "E" was a floating oil storage facility constructed in 1976 and moored approximately 1.2 mi (2 km) from the Brent "A" oil rig. It was jointly owned by Shell and Esso, and operated wholly by Shell, which gave them responsibility for decommissioning the structure. Brent Spar was 482 ft (147 m) high and 95 ft (29 m) in diameter, and displaced 66,000 tonnes. The draft of the platform was such that manoeuvring in the North Sea south of Orkney was not possible. The storage tank section had a capacity of 300,000 barrels of crude oil. This section was built from 0.79 in (20 mm) thick steel plate, reinforced by ribs and cross-braces. It was known that this section had been stressed and damaged on installation. This led to doubts on whether the facility would retain its structural integrity if it was re-floated into a horizontal position.

Shell based its decommissioning decisions on estimates of the quantities of various pollutants, including PCBs, crude oil, heavy metals, and scale, which it had calculated based on the operating activities of the platform, and metal that would remain in the structure after decommissioning. Scale is a by-product of oil production and, because of the radioactivity found in the rocks from which the oil is extracted, is considered to be low-level radioactive waste. It is regularly dealt with on-shore by workers wearing breathing masks to prevent inhalation of dust.^{[citation needed]}

Shell examined a number of options for disposing of the Brent Spar, and took two of these forward for serious consideration.

The first option involved towing the Brent Spar to a shallow water harbour to decontaminate it and reuse the materials used in its construction. Any unusable waste could be disposed of on land. Technically, this option was more complex and presented a greater hazard to the workforce. This option was estimated to cost £41M. There was some concern that the facility would disintegrate in shallow coastal water, having a much more economically and environmentally significant effect.

The second option involved towing the decommissioned platform into deep water in the North Atlantic, positioning explosives around the waterline, then detonating them, in order to breach the hull and sink the platform. The facility would then fall to the seabed and release its contents over a restricted area. Due to the uncertainty associated with detonating explosives, a number of possible scenarios were envisaged. First, the structure would fall to the seabed in one piece, releasing its contaminants slowly, and affecting the seabed for around 1,600 ft (500 m) "down-current". Second, the structure might disintegrate as it fell through the water column. This would release contaminants in a single burst, and have an effect for 3,300 ft (1,000 m) "down current" of the final resting place, although this would last for a shorter time than in the first instance. Third, the structure could fail catastrophically when the explosives detonated, releasing its contaminants into the surface waters. This would affect sea birds and the fishing industry in that area. The cost of this option was estimated at between £17M and £20M.

Shell proposed that deep sea disposal was the best option for Brent Spar, arguing that their decision had been made on sound scientific principles and data. Dismantling the platform on-shore was more complex from an engineering point of view than disposal at sea. Shell also cited the lower risk to the health and safety of the workforce with deep sea disposal. Environmentally, Shell considered that sinking would have only a localised effect in a remote deep sea region which had little resource value. It was considered that this option would be acceptable to the public, to Her Majesty's Government and to regional authorities. Shell acknowledged that sinking the Brent Spar at sea was also the cheaper option.