On 20 March 1970, following a collision involving the Swedish tanker Othello, 60,000 to 100,000 tonnes of heavy fuel oil (IFO 380) were spilt into the sea in Tralhavet Bay (Sweden).
Under the effect of the low temperature (- 10°C at the surface), a large part of the oil turned into blocks, 45 to 60 cm in diameter, which sank to the bottom. The agglomerates measuring a few centimetres in diameter remaining at the surface were burnt using a porous agent composed of fine particles of silica, to pull the fuel to the surface and promote its combustion. The presence of ice in the sea meant that dispersants, sorbents and floating booms could not be used.
The incident resulted in the pollution of around 30 km of coastline, but no damage to flora and fauna was reported.
Date: 20 March 1970
Accident area: Tralhavet Bay, Vaxholm
Cause of spill: collision
Type of pollutant: heavy fuel oil (IFO 380)
Quantity spilled: 60,000 - 100,000 tonnes
Ship type: tanker
Date built: 1969
Last update: April 2009