Report on the investigation of the cargo tank explosion and fire on board the chemical tanker Stolt Groenland, 28 September 2019, Ulsan, Republic of Korea.
This investigation was carried out by the MAIB on behalf of the Cayman Islands Government in accordance with the Memorandum of Understanding (MOU) between the MAIB and the Red Ensign Group Category 1 registries of Isle of Man, Cayman Islands, Bermuda and Gibraltar. It is the first investigation completed in accordance with this MOU.
Summary On 28 September 2019, a cargo tank containing styrene monomer on board the Cayman Islands registered chemical tanker Stolt Groenland ruptured due to runaway polymerisation. The catastrophic rupture released a large quantity of vapour to the atmosphere, and it subsequently ignited. Fire-fighting efforts by the emergency services took over six hours and involved more than 700 personnel and 117 units of fire trucks, pumps and fire tugs.
The key safety issues
The styrene monomer was affected by other heated cargo tanks.Heat transfer from other cargoes was not fully appreciated.The styrene monomer temperature was not monitored.
Safety recommendations
The following safety recommendations are made:Cayman Island Shipping Registry, through the UK Maritime and Coastguard Agency as the Flag State of the Red Ensign Group, is recommended to:
Propose to the IMO a revision to Section 15.13 of the IBC Code to:
– Include in the certificate of protection the actions to be taken in the event of a cargo falling outside of the manufacturer’s specified oxygen and temperature limits, and that
– Any actions should be realistic, taking account of the limitations on board ships regarding the monitoring, adding, and mixing of inhibitor during the voyage.
International Chamber of Shipping is recommended to:
Amend its publication ‘Tanker Safety Guide Chemicals’ to make it clear that:
– The stowage of heated and inhibited cargoes can result in a dynamic situation in which the degree of heat transfer may be complex and difficult to predict.
– One tank separation between heated and heat sensitive cargoes might not be sufficient.
– Promulgate this report to its members.
INTERTANKO is recommended to:
– Promulgate this report to its members.
Chemical Distribution Institute is recommended to:
Amend its publication Chemical Tanker Operations for the STCW Advanced Training Course – A Practical Guide to Chemical Tanker Operations to make it clear that:
– The stowage of heated and inhibited cargoes can result in a dynamic situation in which the degree of heat transfer may be complex and difficult to predict.
– One tank separation between heated and heat sensitive cargoes might not be sufficient.
– Promulgate this report to its members.
Plastics Europe (Styrene Producers Association) is recommended to:
Work with its members to incorporate the lessons learned from this accident in its Styrene Monomer
– Safe Handling Guide.
Stolt Tankers B.V. is recommended to:
Share with INTERTANKO the circumstances and lessons learned from the Stolt Focus incident and the results of its research into:
– Improved stowage software to enable prediction of heat transfer and cargo behaviour.
– The use of in-the-field polymer testing equipment.
