Start with the cargo’s IMSBC schedule
A solid cargo that looks dry and piles like a solid can still present a serious hazard if it contains enough moisture to lose strength and flow. The International Maritime Solid Bulk Cargoes (IMSBC) Code provides cargo-specific information and procedures for safe loading, carriage and discharge. Its hazard framework includes risks such as improper cargo distribution, loss of stability and chemical reactions. Grain in bulk is addressed under a separate code.
Do not infer a cargo’s classification from its commercial name alone or assume that every mineral cargo has the same moisture requirements. Check the applicable IMSBC schedule and confirm the cargo’s declared group and properties with the relevant parties. Group A cargoes are those that may liquefy; for these, the key comparison is between the cargo’s actual moisture content and its transportable moisture limit (TML).
These two figures answer different questions. TML is the limit associated with safe carriage under the Code’s test procedures; moisture content describes the water present in the cargo being offered for shipment. A cargo may be unsuitable for loading if its moisture content exceeds its TML. Neither a cargo’s appearance nor a single convenient field observation should replace the required testing and documentation.
International Maritime Solid Bulk Cargoes (IMSBC) Code — IMO overview · Resolution MSC.500(105): Amendments to the IMSBC Code · Resolution MSC.539(107): 2023 Amendments to the IMSBC Code
Treat TML and moisture content as separate evidence
For a Group A cargo, the shipper must provide the master or the master’s representative with a signed TML certificate and a signed moisture-content certificate or declaration. Under the Code amendments, these documents are to be issued by an entity recognized by the competent authority of the loading port. The shipper is also responsible for establishing procedures for sampling, testing and controlling moisture so that the cargo’s moisture content is below its TML when it is on board.
The records should be checked as a matched set, not as unrelated attachments. Confirm that they identify the cargo being shipped and provide both values; check the issuing entity and the test information required by the Code. If cargo is loaded into multiple holds, the moisture declaration must address the moisture content of each type of finely grained material loaded into each cargo space. That detail helps prevent a general certificate from obscuring differences between cargo lots or holds.
A can test is not a substitute for laboratory testing. The Code describes it as an auxiliary check: if free moisture or fluid conditions appear, additional laboratory tests should be arranged before acceptance. Crucially, a sample that remains apparently dry after the can test may still have moisture content above its TML. A reassuring visual result therefore cannot establish that a cargo is safe to load.
Resolution MSC.500(105): Amendments to the IMSBC Code · Resolution MSC.539(107): 2023 Amendments to the IMSBC Code
Make timing and weather part of the control plan
A certificate is only useful if its sample represents the cargo at the relevant time. The Code places responsibility on the shipper to arrange sampling and moisture testing as near as practicable to the start of loading; the interval must not exceed seven days. If the cargo is exposed to significant rain or snow between testing and completion of loading, the shipper must ensure that its moisture content remains below TML and provide evidence to the master as soon as practicable.
Operationally, this means tracking the sample date, test date, loading start and any significant precipitation during the loading window. If conditions change, do not assume the earlier result still describes the cargo. Follow the applicable sampling and testing procedures and coordinate with the master or representative about the evidence needed before loading continues. The Code also requires frozen cargo samples to be tested for TML or moisture content after free moisture has completely thawed.
Good preparation joins the evidence to the actual cargo: the right schedule, representative samples, valid test records and moisture data that remain relevant through loading. If a cargo is not listed in the Code or its properties are uncertain, do not improvise a classification or rely on a familiar cargo name; seek the applicable competent-authority process and technical guidance before shipment is arranged.
International Maritime Solid Bulk Cargoes (IMSBC) Code — IMO overview · Resolution MSC.500(105): Amendments to the IMSBC Code · Resolution MSC.462(101): Amendments to the IMSBC Code · Resolution MSC.539(107): 2023 Amendments to the IMSBC Code · IMSBC Code, 2025 Edition — IMO Maritime Knowledge Centre bulletin
A practical pre-loading review
Before loading a cargo that may liquefy, verify the schedule and group; match the TML and moisture-content documents to the cargo and, where applicable, the individual cargo spaces; confirm that the issuing entity is recognized by the loading-port competent authority; and check that sampling and testing meet the Code’s timing requirements. Then ask whether rain, snow, thawing or other changes could have altered the cargo since sampling. Resolve gaps before cargo is accepted for loading.
This review is not a substitute for the IMSBC Code, cargo-specific procedures or instructions from the competent authority and master. It is a way to catch common evidence and timing problems early. As of 14 October 2026, the IMO’s 2025 edition incorporates Amendment 08-25, which may be applied voluntarily from 1 January 2026 ahead of its anticipated entry into force on 1 January 2027. Confirm which edition and amendments apply to the voyage and loading arrangements.
International Maritime Solid Bulk Cargoes (IMSBC) Code — IMO overview · IMSBC Code, 2025 Edition — IMO Maritime Knowledge Centre bulletin