Chemical tankers, like oil tankers, transport chemicals in bulk, but while an oil tanker often loads all her tanks with the same product, at the same terminal, a chemical tanker usually has various products in her tanks and loads them in different harbours. For instance, the Ievoli Sun was transporting three different products from two different terminals in two different countries when she sank. (See archive “The products”, in the Ievoli Sun file).
A wide range of products can be transported simultaneously: 30-tank chemical tankers are not rare.
Hazardous products are often present in the cargos and sometimes reactive chemicals can be found next to each other. As a result these vessels are closely inspected and remained under the same ownership for a long time, usually specialised ship-owners. That is also why these vessels have a very low accident rate.
More information about these vessels and their operations can be found in the article (in french) “Chimiquiers, une grande variété de navires” (Chemical tankers, a large range of vessels) by Jean-François Durand, which was published in 10th issue of the magazine “Navires et marine marchande” (Vessels and merchant navy).
It is important to distinguish between chemical tankers and break-bulk vessels used to transport powdery chemicals in bulk, in tanks, in drums or in other packages. It is usually the latter, which are involved in major accidents. In Europe, we can quote, the case of the fire and explosion of the Ocean Liberty loaded with ammonium nitrate in Brest, and in Spain (Cape Finisterre), the grounding and fire of the Cason loaded with various chemicals.
The Bow Eagle has twenty eight tanks, whose capacities vary between 200 and 2,000 cubic meters. According to the stowage plan available, when the accident occured the vessel was transporting nine different products, with a total weight of 23,645 tonnes.
The stowage plan shows particular exposure hazards between toluene and benzene, benzene and ethyl alcohol, toluene and ethyl alcohol. This is acceptable practise according to the current rules, as tanks are totally separated from one another and are equipped with independant pumps and piping.
However in case of a collision or grounding, there is a risk that breaches in tanks could result in mixing hazardous chemicals, the consequences of which could be difficult to assess. In any case, a damaged vessel with possible breaches in neighbouring tanks and/or possible contact between its cargo and sea water can only enter a harbour if the harbour is fully equipped to face the related hazards.