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Thursday, October 18, 2018

Pollution analysis - level of oil spilled in 2006 was one of the lowest for over 35 years

According to the latest annual survey by the International Salvage Union (ISU), the amount of oil spilled in 2006 was at one of the lowest levels for over 35 years. The number of tanker salvage operations also fell to 18 salvage cases involving tankers compared with 34 in 2005. Tankers were involved in only 8% of the total number of salvage cases.


The total amount of oil cargo recovered by ISU members was 566,793 tonnes against 875,331 tonnes in 2005 (the ISU figures refer to cargo and bunkers carried in the vessels which were salved). The amount of crude oil and diesel recovered stood at 400,581 tonnes. Crude and diesel accounted for 71% of the total, while other oil cargoes such as gasoline and dirty ballast represented 15%, bunkers 13% and chemicals 1%. The amount of crude and diesel fell by 25%, bunkers by 10% to 79,943 tonnes, while chemicals saw a sharp decline of 90% to 5,635 tonnes.


The biggest tanker salvage operation involved the ship-to-ship (STS) transfer of 145,396 tonnes of crude. In all, salvors carried out 21 STS operations, compared with 20 in 2005.


Salvage services were rendered to 233 vessels, compared with 247 in 2005. In more than 50 of the cases, the salvage contract employed was the Lloyd's Open Form. Hans Van Rooij, ISU President, said the amount of crude oil involved last year reversed the trend of increased levels of oil cargo recoveries seen in recent years.


The International Tanker Operators Pollution Federation (ITOPF) also recorded an extremely low figure for oil pollution - only counting oil actually spilled. According to the ITOPF figures, the lowest amount of pollution occurred in 2001 when 8,000 tonnes were spilt, while 2006 was, together with 1998, the second best year with 13,000 tonnes of oil spilt.


Looking at the above graph and at this decade, there is no doubt that we have entered a new era with regard to oil spills from tankers. Average pollution, both in the number of large spills and in the total tonnes spilt, declined by some 63% from the 1970s to the 1980s, and by 3%/16% by dwt/number in the 1990s compared to the 1980s. The decline in this decade compared to the 1990s has been 78%/52% by dwt/number.


The best known spill in the 1970s was that of the Amoco Cadiz, which in 1978 spilled 223,000 tonnes off Brittany in France. The biggest spill ever, also in the 1970s, came from the Atlantic Empress, which in 1979 spilt 287,000 tonnes off Tobago, in the West Indies. The best known spill in the 1980s also concerned an oil company tanker, the Exxon Valdez, which in 1989 spilled 37,000 tonnes in the Prince William Sound, Alaska, USA. The biggest spill in the 1980s was that of the Castillo De Bellver, which in 1983 spilt 252,000 Off Saldanha Bay, South Africa.


There were several spectacular spills in the 1990s: the ABT Summer in 1991 spilt 260,000 tonnes of oil 700 nautical miles off Angola; the Haven in 1991 exploded outside Genoa spilling 144,000 tonnes. In 1992 the Aegean Sea spilt 74,000 tonnes after running aground when approaching La Coruna; the Katina P in spilt 72,000 tonnes of oil off Maputo, Mozambique. The Braer in 1993 spilt 85,000 tonnes on the shores of Shetland Islands and the Sea Empress spilt 72,000 tonnes outside Milford Haven.


The three largest oil spills ever recorded by ITOPF were that of the Atlantic Empress in 1979, the ABT Summer in 1991 and the Castillo De Bellver in 1983, but they resulted in very low clean up and damage costs because none of the oil reached the coast line.  It is not necessarily the size of the oil spill that matters most, but the location of the spill, the type of oil, the weather conditions and to some extent the ability of the authorities to limit the damage of the spill.


The most significant oil spills in the last ten years were the Erika, which spilt 20,000 tonnes off France, and the Prestige, which spilt 63,000 tonnes off Spain. These two serious spills were both related to hull damage and involved heavy fuel oil. They both revealed weaknesses in the maritime quality assurance system and resulted in an accelerated phase out of SH tankers and a number of other initiatives and regulations.


Contact: Erik Ranheim