Volume 3, issue #11 - 03-04-1998

Feb. 24, 1998 Ian White, managing director of the International Tanker Owners Pollution Federation (ITOPF) has said that oil spills greater than 700 tonnes have fallen by two-thirds since the 1970s. Dr White, speaking at a conference, said that the declining number of incidents was proof that "efforts to prevent spills had really worked".
Dr White warned that while little has changed in oil spill techniques in the years since the Torrey Canyon spill in 1967 "we need to be aware of what we learnt from major spills". ITOPF has attended 400 spills in 75 countries since 1977, acting on behalf of its members, which comprise 99 % of the world's tanker owners.
Over 85 % of all spills from tankers are less than 7 tonnes with less than 3 % of spills, the majority resulting from collisions and groundings, being over 700 tonnes.
"The volume of oil is by no means the critical factor when determining the impact of an event," Dr White said. Many factors, including the weather conditions, time of year and locality could affect the gravity of a spill he said, adding that "the type of oil and the way it behaves" is the most important factor.
Contrary to public perceptions, oil does not spread in a uniform black layer and 40 % of volume would be lost in 24 hours by evaporation, Dr White told. This was particularly true of non persistent oils, like petrol, which would start to evaporate very rapidly and could be cleaned up far quicker by nature. Persistent oils like bunker fuel were much more problematic, he said, citing as example the Evoikos spill off Singapore last year, where fuel oil "remained on the surface for weeks" because it absorbed water forming an emulsion or "chocolate mousse".
"Fuel oils don't break down naturally and physically smother things," Dr White said. "Some of the most expensive spills have involved heavy fuel oils," he said, adding that the March 1980 spill of 14,500 tonnes of heavy fuel oil from the Tanio off the Brittany coast caused almost as many clean-up problems and was nearly as costly to clean up as the 220,000 tonnes of crude oil from the Amoco Cadiz spill two years earlier on the same stretch of coastline at the same time of year.
A number of options were available for tackling oil spills, Dr White said and "sometimes the weather or sea conditions are so severe that you cannot mount an operation." In the case of the Braer oil spill, 84,000 tonnes of light crude dispersed naturally into the water, he said and said there were many spills where clean up was carried out.
Although the preferred technique was often to concentrate the oil again for manual recovery, Dr White described this as "fighting nature," suggesting a "targeted response is the way to use the recovery method".
There was only 4-8 % recovery in the case of the Exxon Valdez, he added. "The UK is one of few countries truly organised to apply dispersants" as a method of speeding up the natural process, Dr White said.