Brent Spar

Last updated

The Brent Spar oil storage buoy Brent spar.jpg
The Brent Spar oil storage buoy

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)).

Contents

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.

Technical information

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. [1]

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 ]

Disposal options

Shell examined a number of options for disposing of the Brent Spar, and took two of these forward for serious consideration. [2]

On-shore dismantling

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.

Deep sea disposal

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.

Sites considered for sinking of Brent Spar. 1. Maury Channel. 2. North Feni Ridge. 3. Rockall Trough. Brentsparmap.JPG
Sites considered for sinking of Brent Spar. 1. Maury Channel. 2. North Feni Ridge. 3. Rockall Trough.

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.

Having decided on a preferred method of disposal, Shell contracted Fisheries Research Services (FRS) to investigate possible sites for sinking the facility. There were two stipulations to this search: firstly, that the site was within the UK exclusive economic zone, [3] and secondly, that the site be deep enough that the sunken buoy would present no hazard to shipping. FRS identified three sites as 12 by 12 mi (20 by 20 km) squares, which were considered suitable; the Maury Channel, the North Feni Ridge and the Rockall Trough.

At these three sites, FRS carried out:

The North Feni Ridge was found to include a narrow channel. The Rockall Trough area was found to be a gently sloping basin between the Anton Dohrn Seamount and the Wyville-Thomsom Ridge. The Maury Channel area was found to be a flat, gently sloping area.

Infaunal communities were found to be high in diversity and low in abundance, characteristic of unimpacted sediments. These communities were thought to have a limited food supply, which is also normal in deep water communities.

The final conclusions of FRS were that abundance and diversity were greater than had been expected, especially in the North Feni Ridge area, however the limited extent of sampling precluded detailed analysis of data for the entire area. On the basis of the data which FRS gathered, there was little to choose between the three potential disposal areas. Analysis of the North Feni Ridge area may indicate that this area may have been accumulative, but that this would not preclude deep-sea disposal of the platform. [4]

Having received these conclusions, Shell opted for the North Feni Ridge site, and applied to the British government for a licence to dispose of the rig at sea. This was approved in December 1994.

Greenpeace involvement

Greenpeace became aware of the plan to sink the Brent Spar at sea on 16 February 1995. The organization had been campaigning against ocean dumping in the North Sea since the early 1980s, monitoring the dumping of radioactive waste and waste from titanium dioxide production and on occasion using high-seas civil disobedience tactics to physically hinder the perpetrators, and lobbying for a comprehensive ban on ocean dumping through the OSPAR convention. [5]

Greenpeace objected to the plan to dispose of the Brent Spar at sea on a number of issues:

  1. That there was a lack of understanding of the deep sea environment, and therefore no way to predict the effects of the proposed dumping on deep sea ecosystems.
  2. The documents which supported Shell's licence application were "highly conjectural in nature", containing unsubstantiated assumptions, minimal data and extrapolations from unnamed studies.
  3. That dumping the Brent Spar at sea would create a precedent for dumping other contaminated structures in the sea and would undermine current international agreements. The environmental effects of further dumping would be cumulative.
  4. Dismantling of the Brent Spar was technically feasible and offshore engineering firms believed they could do it safely and effectively. The necessary facilities were already routinely in use and decommissioning of many other oil installations had already been carried out elsewhere in the world.
  5. To protect the environment, the principle of minimizing the generation of wastes should be upheld and harmful materials always recycled, treated or contained.

Greenpeace claimed that the scientific arguments for ocean dumping were being used as a way of disguising Shell's primary aim, which was to cut costs. [6] [ citation needed ]

The "battle" of Brent Spar

Four Greenpeace activists first occupied Brent Spar on 30 April 1995. In total, 25 activists, photographers and journalists were involved in this stage of occupation. They decided to cover up the Exxon logos on the platform.[ citation needed ] At this time, activists collected a sample of the contents of the Spar and sent it for testing, to determine the nature of the pollutants which the platform contained. This sample was collected incorrectly, leading to a large overestimate in the contents of the facility. Although Greenpeace quoted Shell's own estimate of the amount of heavy metals and other chemicals on board, they also claimed there were more than 5,500 tonnes of oil on the Spar – while Shell's estimate was 50 tonnes. For context, the Exxon Valdez oil spill involved around 42,000 tonnes.

Greenpeace mounted an energetic media campaign that influenced public opinion against Shell's preferred option. It disputed Shell's estimates of the contaminants on the Brent Spar, saying that these were much more than initially estimated. On 9 May, the German government issued a formal objection to the British government, with respect to the dumping plan. On 23 May, after several attempts, Shell obtained legal permission to evict the Greenpeace protesters from the Brent Spar, and they were eventually taken by helicopter to Aberdeen, Scotland, where they held a press conference.

Towing of the platform to its final position began on 11 June. By this time, the call for a boycott of Shell products was being heeded across much of continental northern Europe, damaging Shell's profitability as well as brand image. German Chancellor Helmut Kohl protested to the British Prime Minister, John Major at a G7 conference in Halifax, Nova Scotia. Support from within the oil industry was not unanimous. Although oil production companies supported Shell's position, influential companies in the offshore construction sector stood to make money from onshore dismantling if a precedent could be set, and consequently supported the Greenpeace point of view.[ citation needed ]

On 20 June, Shell had decided that their position was no longer tenable, and withdrew their plan to sink the Brent Spar. They released the following statement:

"Shell's position as a major European enterprise has become untenable. The Spar had gained a symbolic significance out of all proportion to its environmental effect. In consequence, Shell companies were faced with increasingly intense public criticism, mostly in Continental northern Europe. Many politicians and ministers were openly hostile and several called for consumer boycotts. There was violence against Shell service stations, accompanied by threats to Shell staff."

In early July, the Norwegian government gave Shell permission to mothball the Brent Spar in Erfjord. It remained there for several years while other options for disposal were considered.

Aftermath

Inventory of the Brent Spar
ContaminantShell Co est. (kg)DNV audit est. (kg)
PCBs trace6.5 – 8.0
Hydrocarbons 50,70075,000 – 100,000
Aluminium 28,67724,000 – 40,000
Arsenic 0.30.0
Bismuth 29.00.0
Cadmium 16.41.0–3.8
Copper 13,542.97,500 – 13,200
Indium 10.25.0 – 21.0
Lead 9.50.11
Mercury 0.30.4
Nickel 7.40.9 – 1.5
Silicon 48.00.0
Titanium 8.80.0
Zinc 13,811.45,200 – 8,300
Scale (oil production residue)30,0007800–9400

Having moored the Brent Spar in Erfjord, Shell commissioned the independent Norwegian consultancy Det Norske Veritas (DNV) to conduct an audit of Spar's contents and investigate Greenpeace's allegations. Greenpeace admitted that its claims that the Spar contained 5500 tonnes of oil were inaccurate and apologized to Shell on 5 September. This preempted the publication of DNV's report, which endorsed Shell's initial estimates for many pollutants. [7] Greenpeace noted that its opposition to the dumping had never been solely based on the presence or absence of oil, however, and that opposition to the disposal plan was part of a larger campaign opposing the dumping of all waste into the North Sea.[ citation needed ]

Shell received over 200 individual suggestions for what could be done with the Brent Spar. One of these came from the Stavanger Port Authority. They were planning a quay extension at Mekjarvik, to provide new Roll-On/Roll-Off ferry facilities. It was hoped that using slices of the Spar's hull would save both money and energy that would otherwise have been spent in new steel construction. The Spar was raised vertically in the water by building a lifting cradle, placed underneath the Spar and connected by cables to jacks on board heavy barges. Jacking the cables upwards raised the Spar so that its hull could be cut into 'rings' and slid onto a barge. [8]

After cleaning, the rings were placed in the sea beside the existing quay at Mekjarvik and filled with ballast. The construction of the quay extension was completed by placing a concrete slab across the rings. The Spar's living quarters and operations module were removed and scrapped onshore at a Norwegian landfill site. [9]

While the Brent Spar was being dismantled, quantities of the endangered cold-water coral Lophelia pertusa were found growing on the legs of the platform. [10] At the time, this was considered unusual, although recent studies have shown this to be a common occurrence, with 13 of 14 North Sea oil rigs examined having L. pertusa colonies. [11] The authors of the original work suggested that it may be better to leave the lower parts of such structures in place — a suggestion opposed by Greenpeace campaigner Simon Reddy, who compared it to "[dumping] a car in a wood – moss would grow on it, and if I was lucky a bird may even nest in it. But this is not justification to fill our forests with disused cars". [12]

Effect of Brent Spar

According to a poll of 1000 adults carried out by Opinion Leader Research on 26 January 1996 on behalf of Greenpeace, a majority of the British public were aware of the Brent Spar (57%). Of these, 57% were opposed to the dumping of Brent Spar in the Atlantic, and 32% were in favour of it.

Although Shell had carried out an environmental impact assessment in full accordance with existing legislation, they had severely underestimated strength of public opinion. Shell were particularly criticised for having thought of this as a "Scottish", or "UK" problem, and neglecting to think of the effect which it would have on their image in the wider world. The final cost of the Brent Spar operation to Shell was between £60M [13] and £100M, when loss of sales were considered. Although Shell and the offshore industry consider that Brent Spar did not set a precedent for disposal of facilities in the future, signatory nations of the OSPAR conventions have since agreed that oil facilities should be disposed of onshore, so it is difficult to see how this does not set a precedent. Shell claimed that spending such an amount to protect a small area of remote, low resource value, deep sea was pointless and this money could be much more constructively spent.

The overestimation of the contents of the Brent Spar damaged the credibility of Greenpeace in their wider campaigns. They were criticised in an editorial column in the scientific journal Nature for their lack of interest in facts. [14] Greenpeace moved to distance itself from its "5500 tonnes" claim, after the Brent Spar argument was won.

Timeline

Helicopter crash

Related Research Articles

<span class="mw-page-title-main">Greenpeace</span> Non-governmental environmental organization

Greenpeace is an independent global campaigning network, founded in Canada in 1971 by a group of environmental activists. Greenpeace states its goal is to "ensure the ability of the Earth to nurture life in all its diversity" and focuses its campaigning on worldwide issues such as climate change, deforestation, overfishing, commercial whaling, genetic engineering, anti-war and anti-nuclear issues. It uses direct action, advocacy, research, and ecotage to achieve its goals.

<span class="mw-page-title-main">International Seabed Authority</span> Intergovernmental body to regulate mineral-related activities on the seabed

The International Seabed Authority (ISA) is a Kingston, Jamaica-based intergovernmental body of 167 member states and the European Union established under the 1982 UN Convention on the Law of the Sea (UNCLOS) and its 1994 Agreement on Implementation. The ISA's dual mission is to authorize and control development of mineral related operations in the international seabed considered the "common heritage of all mankind" and also protect the ecosystem of the seabed, ocean floor and subsoil in "The Area" beyond national jurisdiction. The ISA is to safeguard the international deep sea, the waters below 200 meters or 656 feet, where photosynthesis is hampered by inadequate light. Governing approximately half of the total area of the world's oceans, the ISA is to exercise oversight of activities that might threaten biological diversity and harm the marine environment. The Authority operates as an autonomous international organization with its own Assembly, Council and Secretariat.

<span class="mw-page-title-main">Oil platform</span> Offshore ocean structure with oil drilling and related facilities

An oil platform is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms will also have facilities to accommodate the workers, although it is also common to have a separate accommodation platform linked by bridge to the production platform. Most commonly, oil platforms engage in activities on the continental shelf, though they can also be used in lakes, inshore waters, and inland seas. Depending on the circumstances, the platform may be fixed to the ocean floor, consist of an artificial island, or float. In some arrangements the main facility may have storage facilities for the processed oil. Remote subsea wells may also be connected to a platform by flow lines and by umbilical connections. These sub-sea facilities may include one or more subsea wells or manifold centres for multiple wells.

<span class="mw-page-title-main">Brent oilfield</span> Former oilfield in the North Sea

The Brent field was an oil and gas field located in the East Shetland Basin of the North Sea, 186 kilometres (116 mi) north-east of Lerwick in the Shetland Islands, Scotland, at a water depth of 140 metres (460 ft). The field operated by Shell UK Limited was discovered in 1971 and was once one of the most productive parts of the UK's offshore assets but has reached the stage where production is no longer economically viable. Decommissioning of the Brent field is complete with the exception of Brent C, which is producing from another field. The discovery well 211/26-1 was drilled in 1971 by the semi-submersible drilling rig "Staflo". This was a major surprise at the time as the nearest land in Scotland and Norway is composed of granite and other non reservoir metamorphic rocks.

<span class="mw-page-title-main">Seabed</span> The bottom of the ocean

The seabed is the bottom of the ocean. All floors of the ocean are known as 'seabeds'.

<i>Lophelia</i> Species of cnidarian

Lophelia pertusa, the only species in the genus Lophelia, is a cold-water coral that grows in the deep waters throughout the North Atlantic ocean, as well as parts of the Caribbean Sea and Alboran Sea. Although L. pertusa reefs are home to a diverse community, the species is extremely slow growing and may be harmed by destructive fishing practices, or oil exploration and extraction.

The Dunlin oilfield is situated 195 km northeast of Lerwick, Shetland, Scotland, in block number 211/23a and 211/24a. It was originally operated by Shell but was sold in 2008 and is now operated by Fairfield Energy and partners MCX.

The Cormorant oilfield is located 161 kilometres (100 mi) north east of Lerwick, Shetland, Scotland. It was discovered in September 1972 at a depth of 150 metres (490 ft). The oil reservoir is located at a depth of 2,895 metres (9,498 ft). Production started in December 1979 from the Cormorant Alpha platform and operates from two platforms and an underwater manifold centre.

<span class="mw-page-title-main">Offshore drilling</span> Mechanical process where a wellbore is drilled below the seabed

Offshore drilling is a mechanical process where a wellbore is drilled below the seabed. It is typically carried out in order to explore for and subsequently extract petroleum that lies in rock formations beneath the seabed. Most commonly, the term is used to describe drilling activities on the continental shelf, though the term can also be applied to drilling in lakes, inshore waters and inland seas.

Throughout its history, the policies and objectives of the non-governmental environmental protection and conservation organization Greenpeace have been criticized by a number of groups, including national governments, members of industry, former Greenpeace members, scientists, political groups, and other environmentalists. The organization's methods, such as the use of direct action, have also led to controversy and legal action.

<span class="mw-page-title-main">Sleipner gas field</span> North Sea off Norway

The Sleipner gas field is a natural gas field in the block 15/9 of the North Sea, about 250 kilometres (160 mi) west of Stavanger, Norway. Two parts of the field are in production, Sleipner West, and Sleipner East (1981). The field produces natural gas and light oil condensates from sandstone structures about 2,500 metres (8,200 ft) below sea level. It is operated by Equinor. The field is named after the steed Sleipnir in Norse mythology.

<span class="mw-page-title-main">Spar (platform)</span> Marine structure used for floating oil/gas platforms

A spar is a marine structure, used for floating oil/gas platforms. Named after navigation channel Spar buoys, spar platforms were developed as an extreme deepwater alternative to conventional platforms. The deep draft design of spars makes them less affected by wind, wave, and currents and allows for both dry tree and subsea production.

<span class="mw-page-title-main">Rigs-to-Reefs</span> Program for converting decommissioned offshore oil and petroleum rigs into artificial reefs

Rigs-to-Reefs (RTR) is the practice of converting decommissioned offshore oil and petroleum rigs into artificial reefs. Such biotic reefs have been created from oil rigs in the United States, Brunei and Malaysia. In the United States, where the practice started and is most common, Rigs-to-Reefs is a nationwide program developed by the former Minerals Management Service (MMS), now Bureau of Safety and Environmental Enforcement (BSEE), of the U.S. Department of the Interior.

George Albert Esson was Assistant Chief Constable of Grampian Police and Chief Constable of Dumfries and Galloway Constabulary (1989-1994). He was at the centre of major inquiries into the Piper Alpha disaster and the 1986 Chinook Helicopter Crash. He also headed the police investigation into the Lockerbie Bombing.

<span class="mw-page-title-main">Suction caisson</span> Open bottomed tube anchor embedded and released by pressure differential

Suction caissons are a form of fixed platform anchor in the form of an open bottomed tube embedded in the sediment and sealed at the top while in use so that lifting forces generate a pressure differential that holds the caisson down. They have a number of advantages over conventional offshore foundations, mainly being quicker to install than deep foundation piles and being easier to remove during decommissioning. Suction caissons are now used extensively worldwide for anchoring large offshore installations, like oil platforms, offshore drillings and accommodation platforms to the seafloor at great depths. In recent years, suction caissons have also seen usage for offshore wind turbines in shallower waters.

<span class="mw-page-title-main">Arctic policy of Russia</span> Russia and the Arctic

The Arctic policy of Russia is the domestic and foreign policy of the Russian Federation with respect to the Russian region of the Arctic. The Russian region of the Arctic is defined in the "Russian Arctic Policy" as all Russian possessions located north of the Arctic Circle. Approximately one-fifth of Russia's landmass is north of the Arctic Circle. Russia is one of five littoral states bordering the Arctic Ocean. As of 2010, out of 4 million inhabitants of the Arctic, roughly 2 million lived in arctic Russia, making it the largest arctic country by population. However, in recent years Russia's Arctic population has been declining at an excessive rate.

From 1946 through 1993, thirteen countries used ocean disposal or ocean dumping as a method to dispose of nuclear/radioactive waste with an approximation of 200,000 tons sourcing mainly from the medical, research and nuclear industry.

This is a list of notable events relating to the environment in 1995. They relate to environmental law, conservation, environmentalism and environmental issues.

<i>Kulluk</i>

Kulluk was an ice-strengthened drill barge that was used for oil exploration in the Arctic waters. She was constructed by Mitsui Engineering & Shipbuilding in Japan in 1983 and operated in the Canadian Arctic until 1993 when she was mothballed for over a decade. In 2005, she was purchased and extensively refurbished by Royal Dutch Shell for drilling off the Alaska North Slope.

Gannet is an oil and gas field located in the United Kingdom's continental shelf in the North Sea. It is 180 km (110 mi) east of Aberdeen, and the water depth at the Gannet offshore installation is 95 m (312 ft). The field is located in Blocks 22/21, 22/25, 22/26 and 21/30. It is half-owned by Royal Dutch Shell (50%) and partly by ExxonMobil (50%) and has been operated by Shell UK Ltd since ‘first oil’ in November 1993. The Gannet A installation is the host platform for subsea tiebacks designated Gannet B to G. Like most Shell fields in the central and northern North Sea the field is named after a sea bird the gannet.

References

  1. "Structural damage danger for Brent Spar". Chemical Engineer. 7. London: 615–616. 1996.[ verification needed ]
  2. "Brent Spar". Shell. Archived from the original on 24 November 2007.
  3. Owen & Rice 1999, p. 38.
  4. "Case study: Brent Spar" (PDF). Fisheries Research Services. Archived from the original (PDF) on 15 May 2006.
  5. Parmentier, R, "Greenpeace and the Dumping of Wastes at Sea" Archived 28 May 2015 at the Wayback Machine , 1999
  6. Nash, Nathaniel C. (23 June 1995). "A Humbled Shell Is Unsure On Disposal of Atlantic Rig". The New York Times.
  7. "DNV Inventory". Contents of Brent Spar, relative to quantities in the North Sea, as detailed by Det Norske Veritas. Archived from the original on 27 September 2007. Retrieved 10 March 2005.
  8. "News". Marine Pollution Bulletin. 38 (2): 67–70. February 1999. Bibcode:1999MarPB..38...67.. doi:10.1016/S0025-326X(99)90003-6.
  9. "Brent Spar gets chop". BBC News. 25 November 1998.
  10. Smith, Craig A.; McClive, Peter J.; Western, Patrick S.; Reed, Kirsty J.; Sinclair, Andrew H. (December 1999). "Conservation of a sex-determining gene". Nature. 402 (6762): 601–602. doi:10.1038/45130. PMID   10604464. S2CID   4431862.
  11. Gass, Susan E.; Roberts, J. Murray (May 2006). "The occurrence of the cold-water coral Lophelia pertusa (Scleractinia) on oil and gas platforms in the North Sea: Colony growth, recruitment and environmental controls on distribution". Marine Pollution Bulletin. 52 (5): 549–559. Bibcode:2006MarPB..52..549G. doi:10.1016/j.marpolbul.2005.10.002. PMID   16300800. INIST   17830117.
  12. "Oil rig home to rare coral". BBC News. 8 December 1999.
  13. "Brent Spar Outcry Leaves Shell with a 60 m Pound Bill". Professional Engineering. 12 (16): 9. 1999.[ verification needed ]
  14. "Brent Spar, broken spur". Nature. 375 (6534): 708. June 1995. Bibcode:1995Natur.375..708.. doi: 10.1038/375708a0 . S2CID   4369687.
  15. "BBC apologises to Greenpeace". BBC News. 25 November 1999.
  16. "Aircraft accident report 2/91" (PDF). Retrieved 20 November 2012.
  17. "Appendices" (PDF). Retrieved 20 November 2012. in "Report on the accident to Sikorsky S-61N, G-BEWL at Brent Spar, East Shetland Basin on 25 July 1990".

Sources

Further reading

61°03′N1°40′E / 61.050°N 1.667°E / 61.050; 1.667