Evolution of spills
Statistics show that the number and total volume of oil spills from loaded oil tankers have been considerably decreasing since the historic peak of 750,000 tonnes in 1979.
For instance, thanks to a major prevention effort implemented following the Amoco Cadiz spill (1978), France experienced only four persistent oil spills of over a thousand tonnes in the following twenty years: those of tankers Gino (1979 – 40,000 tonnes of carbon black spilt on the seafloor off Ouessant Island, Brittany), Tanio (1980 – broke in two north of Batz Island with 26,000 tonnes of fuel oil onboard, of which 6,000 were released at sea), Amazzone (1988 – just over 2,000 tonnes of fuel oil spilt off the coast of Finistère) and Lyria (1991 – some 2,200 tonnes of oil spilt off the coast of Provence). However, the sinking of the Erika, in December 1999, reminded one and all that oil spills continue to be a permanent threat.
Other countries have also been victim to oil spills of varying intensities over the past years. That of the Prestige, which began on 13 November 2002, showed once again that these spills pay no heed to international borders and can affect several countries (e.g. Torrey Canyon in 1967, Vistabella in 1991) when they occur offshore, due to the sinking of a passing ship. However, passing ships are not the only ones to blame. Collisions and accidents near ports and harbours are almost as present in the world oil spill balance. In addition, thankfully as exceptional cases, offshore oil rig accidents and acts of war have their share in this balance.
Among accidents occurring near ports and harbours, the UK faced a 73,000 tonne spill by the Sea Empress at Milford Haven in 1996, while France was managing a mere 180 tonne spill from the Katja in Le Havre (1998).
As for collisions, Singapore was victim to a 25,000 tonne spill in 1998 by the Evoikos, while France was lucky enough that the latest oil tanker collision off its coast involved a tanker carrying super unleaded petrol (Bona Fulmar, 1997) and an empty tanker (Nilos, 1998).
In the case of vessels sinking and grounding, a 6,000 tonne spill of heavy fuel oil spilt by the Russian oil tanker Nakhodka in 1997 hit Japan, while France was dealing with a far smaller spill of 120 tonnes of heavy fuel oil from the cargo ship Capetan Tzannis in Anglet. However, the difficulties encountered by the Japanese authorities due to the Nakhodka spill were a precursor to those France was later to encounter with the Erika spill and Spain with the Prestige . A number of lessons from the Japanese experience were in fact a useful reference for French decision-makers.
Oil production and storage
Finally, several recent accidents or malicious acts, particularly in Latin America, have shown that the risks of pollution associated with, on the one hand, oil production and, on the other, oil transport by pipelines, must not be neglected, even if we remain far from the tragic records of oil spilt in the Gulf of Mexico recently by Deepwater Horizon (2010) or previously by Ixtoc 1 (1979). The storage of petroleum products or chemicals and their transport by road, river or rail are also causes of spills liable to generate problems for responders.
There are numerous examples of spills at sea of heavy petroleum products, crude oil or refined products with a density between 0.95 and 1.00. In France, reference can be made to four spills:
Overseas, the most significant spills of heavy fuel oil (n°6) or intermediate fuel oil (IFO 380) are the following:
These types of spills produce large patches of oil, patties and tarballs, resulting from the fragmentation of the product as it drifts at sea, often accompanied by sheen. Most of the time, they generate heavy impact due to the smothering of sea birds and mammals.
As there is only a small proportion of evaporable and biodegradable components in heavy fuel oil (less than 10% of the mass), such spills require considerable clean-up efforts, made difficult by the product’s extreme viscosity. By way of compensation, such products emit few toxic elements in water and, once clean-up has been completed, the long term effects are generally minimal.
Every incident is unique
Every incident locally generates a wave of questioning on the procedures, techniques, equipment and products used. This wave moves forward, to a greater or lesser extent, response know-how and means. After each incident, information useful to operational staff must therefore be sought out in the affected countries. Some more severe or more media-exposed accidents raise national, or sometimes even larger scale, awareness, leading to new experiments. The spills caused by the Amoco Cadiz (1978) and the Erika (1999) thus resulted in amendments to the national legislation in response to accidental marine pollution (Instruction Polmar). The Erika spill generated a set of European measures (Erika “packets” I, II and III).