On 6 March 1987, the British car ferry Herald of Free Enterprise was leaving the port of Zeebrugge (Belgium) while the doors were still open due to an officer’s carelessness. Water rushed inside the ship with a flow rate of 200 tonnes per minute. Destabilized by the volume of water and by the sliding of vehicles on her left side, the ferry capsized and sank 10 m deep near the port.
Operations were carried out to rescue the crew and the passengers. The other priority was to recover the cargo which was made up of 46.6 tonnes of various dangerous chemicals.
In this shipwrecking, about 200 people were drowned, and several containers, drums and bottles of chemicals were lost at sea. It remained difficult to assess the environmental hazard the dangerous cargo constituted, because so little was known of the toxicity of most of the chemicals for marine organisms. Moreover, an important factor to take into consideration was the fact that once released into the marine environment many chemicals react or degrade to form potentially toxic substances.
Firstly, a simplified scenario was used to quickly determine the extent of the sea area in which concentrations considered lethal for marine organisms could be reached. Then, environmental monitoring was performed in order to ensure the safety of personnel involved in operations and also to assess the extent and impact of a possible spill in the marine environment.
Refloating the ferry took 52 days and represented a major technical achievement. Although only half of the dangerous cargo was recovered, environmental damage was kept to a minimum.
Sources:
Name: Herald of Free Enterprise
Date: 6 March 1987
Location: Belgium
Accident area : Port of Zeebrugge
Cause of spill : loading mistake
Quantities transported : 46.6 tonnes of dangerous chemicals: 19.9 tonnes of tribasic lead sulphate + 5.5 tonnes of toluene di-isocyanate + 7.8 tonnes of paint wastes + 5 tonnes of hydroquinone + 5 tonnes of leather paint + 400 kg of diluted cyanide solutions + 260 kg of liquefied and pressurized gases
Type of pollutants : over 100 different dangerous chemicals including : tribasic lead sulphate, toluene di-isocyanate, paint wastes, hydroquinone, leather paint, diluted cyanide solutions, 13 types of liquefied and pressurized gases (such as chlorine trifluoride, hydrogen bromide …)
Ship type : car ferry
Date built : 1980
Shipyard : Schichau Unterweser, Bremerhaven, Germany
Length : 131.91 m
Width : 22.19 m
Draught : 5.72 m
Flag : British
Owner: Compañía Naviera S.A., Athens, Greece
Operator : Townsend Thoresen, Great Britain
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Last update: 30/11/2009