Key takeaways
Group A cargoes pose liquefaction risks
Moisture content must be below TML to ensure safe shipment.
Chrome ore may behave like Group A cargo
Testing and certification are essential even if declared as Group C.
Compliance with IMSBC code is mandatory
Owners can insist on full procedures, including competent authority approval.
This article provides a brief summary of the rules and requirements surrounding the shipment of cargoes that are prone to liquefying and highlights some recent concerns arising around the shipment of cargoes that may be officially classified as cargoes which are not liable to liquefy (Group C) when, in fact, they may act as Group A cargoes.
Background
Liquefaction of fine-particled cargoes, resulting in liquefaction and loss of stability, has been associated with the loss of life in numerous, recent marine casualties.
The International Maritime Solid Bulk Cargoes (IMSBC) Code establishes international provisions for transporting solid bulk cargoes by sea, ensuring compliance with the SOLAS Convention and aims to minimize the risks associated with such cargoes. The IMSBC Code is mandatory under SOLAS. The latest amendments to the IMSBC Code came into force on 1 January 2025 (but with voluntary implementation having been effective since 1 January 2024).
IMSBC Code: classification of cargoes
The IMSBC Code classifies such cargoes as follows:
Group A consists of cargoes which may liquefy if shipped at a moisture content in excess of their transportable moisture limit (TML).
Group B consists of cargoes which possess a chemical hazard which could give rise to a dangerous situation on a ship.
Group C consists of cargoes which are neither liable to liquefy (Group A) nor possess chemical hazards (Group B).
IMSBC Code: Section 4
Section 4 addresses the assessment of acceptability of consignments for safe shipment. This covers among other things: identification and classification (s.4.1); provision of information (s.4.2); certificates of test (s.4.3); and sampling procedures (s.4.4).
S.4.3.3 provides as follows:
“When a concentrate or other cargo which may liquefy is carried, procedures for sampling, testing and controlling moisture content to ensure the moisture content is less than the TML when it is on board the ship shall be established by the shipper, taking account of the provisions of this Code. Such procedures shall be approved and their implementation checked by the competent authority of the port of loading. The document issued by the competent authority stating that the procedures have been approved shall be provided to the master or his representative.”
IMO Guidelines
The International Maritime Organization (IMO) has published guidelines on the preparation, approval and implementation of procedures for sampling, testing and controlling moisture content for solid bulk cargoes which may liquefy (MSC.1/Circ.1454 – see Revision 2, dated 26 June 2023).
The Guidelines aim to complement the provisions of the IMSBC Code by:
assisting shippers in preparing procedures for sampling, testing and controlling moisture content as required by paragraph 4.3.3 of the IMSBC Code; and
assisting competent authorities of ports of loading when approving and checking the implementation of such procedures in accordance with paragraph 4.3.3 of the IMSBC Code.
The Guidelines state that, before any transport of Group A cargoes, the shipper should establish the procedures set out in sections 2 to 4 of the Guidelines and should provide them well in advance to the competent authority of the port of loading for approval.
As defined in Section 1.7 of the IMSBC Code (Definitions), the competent authority means any national regulatory body or authority designated or otherwise recognized as such for any purpose in connection with the IMSBC Code.
Group A or Group C cargo?
The shippers are responsible for correct declaration, certification and testing of the cargo.
Cargoes may be identified by, and shipped pursuant to, their Bulk Cargo Shipping Name (BCSN). The BCSN will identify the relevant schedule and requirements of the IMSBC Code.
The list of Group A cargoes is regularly updated in the IMSBC Code and the related cargo schedules. However, the Group A classification is not definitive. As stated in s.1.2.1 of the Code, schedules for individual cargoes are not exhaustive, and the properties attributed to the cargoes are given only for guidance. Consequently, before loading, it is essential to obtain current valid information from the shippers on the physical and chemical properties of the cargoes presented for shipment, specifically satisfactory certification for TML and moisture content which is valid up to 7 days before loading.
Mineral concentrates
The list of Group A cargoes is regularly updated. The majority of Group A cargoes are mineral concentrates. Section 1.7 of the Code defines concentrates as follows:
“Concentrates means materials obtained from a natural ore by a process of enrichment or beneficiation by physical or chemical separation and removal of unwanted constituents.”
As at October 2025, Group A cargoes include nickel ore, bauxite fines and iron ore fines. These three Group A schedules were introduced in recent years in response to a number of vessels being lost as a result of cargo liquefaction at a time when nickel ore was unlisted and iron ore and bauxite were listed as Group C.
The Code includes chrome concentrate under the schedule for CHROMITE ORE, listed as a Group C cargo, rather than in the list of mineral concentrates, but it can exhibit Group A characteristics if it contains sufficiently fine particles to develop a flow state at high moisture content.
Appendix 3 of the Code provides as follows:
“2.1 Many fine-particled cargoes, if possessing a sufficiently high moisture content, are liable to flow. Thus any damp or wet cargo containing a proportion of fine particles should be tested for flow characteristics prior to loading.”
Due to this risk, it is recommended for such a cargo to be properly tested to ensure it is safe for shipment before being declared as Group C. There have in fact been reported incidents of chrome concentrate liquefying during passage in circumstances where the cargo had been declared as Group C.
Shipper’s declaration
Where the shipper declares chrome ore as Group C, but the master/owners believes it should be certified as Group A because the cargo loaded does not match the cargo declaration provided, then the owners and their P & I Club may insist on full compliance with s.4.3.3 and other IMSBC Code provisions for Group A cargoes.
Concerns may arise with regard to the fact that the required competent authority approval may take some considerable time to obtain, particularly where the authority in question is strictly enforcing the requirement for a moisture management plan (MMP) under s.4.3.3. This could potentially result in abandonment of the voyage unless it is possible to implement an abbreviated approval procedure. Nonetheless, the Code is mandatory, owners are entitled to require full compliance and shippers should put into motion all necessary procedures for sampling, testing and certification in good time.
Other potential steps for the Owners/Master to take include:
Requiring shippers to reissue the declarations as Group A cargoes and/or obtaining a certificate from the competent authority that the cargo is Group A.
Stockpiles should be sampled by a suitable representative method.
The samples to be tested for TML and moisture content.
The stockpiles to be protected from rain after sampling.
Any visibly wet cargo to be rejected during loading.
After loading, the cargo in all holds to be trimmed flat across the entire width of the cargo holds.
Comment
The regulatory and practical issues surrounding the shipment of Group A cargoes, including chrome ore/chrome concentrates, should be navigated very carefully, pending any changes to the classification of such cargo under the Code.
This article was written in conjunction with Martin Jonas of Brookes Bell.
In the event of any query, please contact Tom Burdass or your usual contact at Hill Dickinson LLP.
