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Risk of spills of oil and hazardous substances


The BRISK model provides a detailed picture of the risks associated with spills of oil and hazardous substances in the Baltic Sea. The risk of spills at sea originates essentially from two types of events:

  • Deliberate and inadvertent action (illegal spills)

  • Accidents at sea

The modelling is covering different sizes of spills, including the largest possible spills in the Baltic taking into account the depth of the sea and the size of the tankers that can enter the area.

Small and accidental spills

Risk of small spills_450p.jpg
Risk of small and medium spills up to 300 tonnes.
The HELCOM statistics on observed illegal spills for 2005-2009 has been expressed as the number of spills per sailed nautical mile for different sub-areas in the Baltic Sea. The resulting numbers have been overlaid with the numbers representing the risks of smaller accidental spills of oil of up to 300 tonnes.

The illegal spills dominate the overall picture of small spills. When compared with the traffic intensity, one could see areas in the Baltic Sea where ships sail more “clean”, with less illegal spills. 

Deliberate and inadvertent action is expected to result in a spill of approximately 500 tonnes of oil per year. 92% percent of the overall spill tonnage is due to the small spills (less than one tonne). Only 1.3% of the overall spill is caused by events that are larger than 10 tonnes. Almost 90% of the spilt oil is volatile and will typically disappear before it could be contained.

Thus, deliberate and inadvertent spills have almost no importance for the planning and deployment of emergency and response capacities.

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Larger accidental spills

Risk of exceptional spills 5.000 and above in the Baltic Sea

The risks of exceptional spills of 5,000 tonnes and above is related to possible accidents of oil tankers, and is concentrated along the main tanker route, including route junctions in the Baltic Proper and Kattegat as well as narrow straits that lead to the Baltic Sea through the Great Belt.


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Risk of large spills 300 to 5.000 tonnes in the Baltic Sea

Large spills of 300-5,000 tonnes might not pose the same risk as exceptional spills, but they are much more frequent. Large spills are not restricted to the main oil shipping route, but are more evenly distributed throughout the Baltic Sea and as likely on some other routes, particularly in the waters of Gotland, the Åland archipelago and along the Polish coast.


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Expected intervals between spill events 

The risks can also be expressed as the expected intervals between spills of a specific size range, for the whole Baltic Sea or in different sub-regions. A spill in a range of 5,000 tonnes and above could occur once every 26 years, while a spill in a range of  300-5,000 tonnes is expected to occur as frequently as once every 4 years. The biggest risk areas are the south-western Baltic and the Kattegat.


Large accidents:
300-5.000 tonnes spilt

Exceptional accidents:
5,000 tonnes and above spilt

1. Gulf of Bothnia

   36 years

  600 years 

2. Gulf of Finland

   39 years

  255 years

3. Northern Baltic Proper

   30 years

  175 years

4. South-eastern Baltic Proper

   140 years

  1,060 years

5. South-western Baltic Proper

   17 years

  97 years

7. Sound and Kattegat

   11 years

  65 years

Entire Baltic Sea

   4 years

  26 years

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