Cargo liquefaction is the process by which a Group A solid bulk cargo containing moisture progressively loses shear strength under the cyclic motion and vibration of a ship. As inter-particle pore-water pressure rises faster than the water can drain, effective stress between grains falls toward zero, the cargo transitions from a packed solid to a dense fluid, and the resulting free liquid surface shifts with every roll. Ships have capsized in under twenty minutes once liquefaction begins, often at night, with few survivors and no recovery of the vessel. The Intercargo Bulk Carrier Casualty Report 2025 attributes 55 seafarer deaths, 61.8% of all bulk-carrier fatalities in the decade 2015 to 2024, to this single mechanism.
The regulatory control is the Transportable Moisture Limit (TML), set at 90% of the Flow Moisture Point (FMP) under the IMSBC Code. A Group A cargo may be loaded on an ordinary bulk carrier only when its declared moisture content is strictly below the certified TML. That single rule is the whole of the Group A safety regime in one sentence; the test methods, the certificates, the shipboard checks, and the master’s refusal right all exist to prove and defend it.
For the per-cargo group, test method, and bulk density data for specific schedules, use the IMSBC bulk cargo finder at /calculators/imo-imsbc. For moisture compliance on iron ore fines specifically, the iron ore fines moisture calculator supports the TML check. For nickel ore, the nickel ore flow moisture point calculator covers the FMP determination side.
The soil mechanics of liquefaction
Effective stress and pore-water pressure
A bulk cargo in a ship’s hold is a granular mass: millions of particles pressed together with water-filled spaces between them. The load is carried by grain-to-grain contact, and it is that contact, the normal force pushing grains together, that gives the mass its strength. Soil mechanics measures this as effective stress:
where is total stress (the weight of cargo above a given plane), is pore-water pressure (the pressure of water in the voids), and is effective stress, the part of the total load actually carried by grain contacts. Shear strength is proportional to effective stress: when is high, grains interlock and the mass is solid; when approaches zero, grains barely touch, and the mass flows.
Ship motion applies this test repeatedly. Rolling, pitching, and slamming drive cyclic shear into the cargo. Each shear cycle compacts the grain structure slightly, shrinking the void spaces. In a coarse cargo, the water simply runs out faster than it is squeezed and stays low. In a fine, low-permeability cargo, the water cannot escape fast enough, so each compaction pulse pushes a little higher. As climbs, falls. When moisture is at or above the TML, this process can run until the grains are floating in the interstitial water and is effectively zero. The cargo is now a fluid, not a solid.
From solid to fluid: the sequence in a hold
The transition runs faster than most officers expect. The first sign is often that the cargo surface in a partially loaded hold looks darker or shinier than it did at departure. A few hours later the bilge wells begin to fill with water carrying fine particles. By the time a visible list develops, a large volume of cargo has already gone fluid on the low side. The free liquid surface then amplifies every roll: the fluid shifts to the low side on each oscillation, adding a dynamic heeling moment to the lost righting moment from the now-absent metacentric height. Ballast correction cannot keep up with a heeling moment that resets every roll. Capsize follows when the cumulative effect exceeds the vessel’s remaining stability.
One important mechanical detail: the cargo does not need to liquefy uniformly through its full depth to capsize the ship. Partial liquefaction at the base of a loaded hold, where overburden stress is highest and pore pressure builds fastest, is enough to let the overlying solid cargo slide as a block on each roll cycle. The visible surface above looks dry and solid. Officers have no bridge instrument that detects pore pressure in the cargo; the only observable signs, a softening of roll, a developing list, or rising bilge levels, appear after the process is well advanced.
Why fine cargoes liquefy and coarse ones do not
The hazard divides on permeability. Permeability, the ease with which water drains through a porous mass, scales roughly with the square of particle size. A cargo of gravel has permeability orders of magnitude higher than a cargo of fine mineral concentrate ground to 100 micrometres. The gravel drains faster than compaction can build pressure, so effective stress stays positive and the cargo stays solid no matter how much the ship moves. The fine concentrate traps water, builds pressure, and liquefies when moisture is high enough.
This is why the IMSBC Code’s Group A schedules turn on particle size and moisture, and why a cargo that looks like a firm, manageable pile at the stockpile can still be a liquefaction risk if the fines fraction is saturated. A cargo whose surface layer is dry but whose interior contains a wet fine fraction can liquefy in the holds even after a clean visual inspection at the berth.
The TML and FMP framework
Three quantities govern Group A carriage under the Code.
Moisture content (MC) is the mass of water in the cargo expressed as a percentage of the total wet mass, determined by drying representative samples.
Flow moisture point (FMP) is the moisture content at which a representative sample first begins to flow under the prescribed laboratory agitation, the threshold at which the effective stress in the tested material reaches zero under the test conditions.
Transportable moisture limit (TML) is the maximum MC the Code permits for loading on an ordinary bulk carrier. For the flow-table and penetration tests:
The 10% margin is not arbitrary. It absorbs measurement scatter in both the FMP test and the moisture sampling, accounts for moisture pickup between testing and the end of the voyage, and acknowledges that the FMP is measured under controlled laboratory agitation while the cargo in the hold is subjected to the far more energetic motion of a seaway. Proctor-Fagerberg methods derive the TML directly from a moisture-density relationship without computing an FMP first, so the formula does not apply to those methods, but the underlying principle, a safety margin from the physical flow threshold, is identical.
The carriage rule is binary: if MC is less than TML, loading may proceed; if MC equals or exceeds TML, loading must stop. There is no graduated scale and no “close enough.” A cargo at exactly the TML is prohibited, not marginal.
Certificate timing
The two certificates run on different clocks because they measure different things. TML is a physical property of the cargo type, stable over months, and its certificate is valid for up to six months before loading. Moisture content is a condition that changes with weather, handling, and drainage; its certificate must be dated within seven days before the start of loading. If rain or snow falls between the MC sampling date and the first grab, the MC certificate is void and the cargo must be retested before loading resumes. P&I casualty analyses consistently flag this as a point of failure: shippers have presented original MC certificates without retesting after significant rainfall, loading cargo that was already above TML at the berth.
TML test methods
Appendix 2 of the IMSBC Code now prescribes six test methods, up from three in the editions that predated the 2017 and 2021 amendments. The method is specified by the cargo schedule and cannot be freely chosen; a TML obtained by the wrong method is not a valid certificate.
| Test method | Principle | Applicable cargo | TML derivation |
|---|---|---|---|
| Flow table test | Repeated drops of a table; visual assessment of flow onset | Fine materials up to ~1 mm (some protocols to 7 mm) | TML = 0.9 × FMP |
| Penetration test | Oscillating platform; objective penetration depth measurement | Materials up to 25 mm top size | TML = 0.9 × FMP |
| Proctor-Fagerberg (PFC70) | Compaction curve; 70% saturation at optimum moisture | Most mineral concentrates up to ~5 mm | TML from compaction-saturation curve |
| Modified PF for iron ore fines (PFD80) | Lighter hammer; 80% saturation threshold | Iron ore fines (mandatory since 1 January 2017) | TML from compaction-saturation curve |
| Modified PF for coal | Larger mould; reconstitution step for coarse particles | Coal assessed as Group A | TML from compaction-saturation curve |
| Modified PF for bauxite | Tuned to bauxite drainage behaviour | Bauxite fines (Group A schedule, mandatory 1 January 2021) | TML from compaction-saturation curve |
The Proctor-Fagerberg family
The Proctor-Fagerberg methods deserve specific attention because they are the modern direction of travel and because the modifications to the standard method carry regulatory significance.
The original method borrows from geotechnical soil compaction. A sample is compacted into a cylindrical mould in several layers using a standard hammer, and the dry density and moisture content are measured at each run. Multiple runs at different moisture levels trace a compaction curve that peaks at the optimum moisture content (OMC), the point of densest packing. The degree of saturation (the fraction of void space occupied by water) at the OMC is then read off, and the TML corresponds to the moisture content producing 70% saturation at that optimum point.
The modified method for iron ore fines (PFD80) uses a lighter hammer and sets the saturation threshold at 80% rather than 70%. This matters because iron ore fines genuinely reach a higher saturation at their OMC than a typical mineral concentrate, so applying the 70% criterion would place the TML too high for that material and understate the risk. The 80% threshold was the product of the Indian Government’s inquiry after the 2009 losses and was made mandatory for iron ore fines from 1 January 2017.
The bauxite modification was developed by the Global Bauxite Working Group after the 2015 Bulk Jupiter casualty, tuned to the specific drainage behaviour of bauxite fine fractions. Separate modifications for coal reflect coal’s different compaction behaviour and the larger particle sizes in typical run-of-mine and washed coal products.
For a given sample, the flow-table and penetration tests typically produce a more conservative (lower) TML than the Proctor-Fagerberg methods. This has commercial weight: a higher certified TML lets a shipper load wetter cargo. P&I clubs have documented cases where different test laboratories produced TML values differing by 2 to 3 percentage points on the same cargo, which is enough to move a borderline moisture content from compliant to prohibited.
The can test
The can test is set out in Section 8 of the IMSBC Code as a rapid shipboard screening check that a ship’s officer can run during loading with no laboratory equipment.
The procedure is straightforward. Take a representative sample from the loading stream and half-fill a cylindrical metal container of 0.5 to 1 litre. Bring the can sharply down onto a hard surface from a height of approximately 0.2 metres and repeat 25 times at one- to two-second intervals. Then examine the cargo surface.
The interpretation is deliberately asymmetric. If free moisture appears at the surface, the cargo is suspect: loading should stop immediately and the master should arrange independent laboratory testing before any decision about resuming. That positive result is actionable. A dry result, however, does not confirm the cargo is below its TML. A cargo at 95% of TML can pass the can test while still presenting real risk. The Code explicitly states this limitation, and it is the one thing about the can test that officers most often misunderstand.
Officers should perform can tests at the start of each loading shift and whenever the cargo stream changes in appearance or consistency. Blending of batches with different moisture histories, rehandling of stockpiled cargo after rainfall, or a switch to a different stockpile location can all raise the effective moisture without any change in documentation.
Dynamic separation
Dynamic separation is a related but distinct mechanism added to the Group A definition by Amendment 06-21, adopted in IMO Resolution MSC.500(105) and mandatory from 1 December 2023. The IMSBC Code defines it as “the phenomenon of forming a liquid slurry (water and fine solids) above the solid material, resulting in a free surface effect which may significantly affect the ship’s stability.”
In classical liquefaction the cargo transitions to a fluid state throughout its depth, or at least through a substantial layer. In dynamic separation the lower bulk remains solid while ship motion drives fine particles and free water upward through the mass to form a slurry layer at the surface. That surface slurry produces a free surface effect indistinguishable in its stability consequences from full liquefaction. The underlying bulk cargo can appear stable, and the bilge wells can remain dry, because the water is not migrating downward into the wells but upward into the surface layer. This means the observable warning signs of classical liquefaction, rising bilge levels and a fluid appearance at the cargo surface, may not appear until the slurry layer is well developed.
Dynamic separation is the mechanism associated with bauxite fines and also with certain fine coals. The Bulk Jupiter investigation concluded that this, not classical liquefaction, was the operative mechanism in that casualty: the lower layers of bauxite remained effectively solid while the fine fraction and water migrated to form a mobile slurry surface. The regulatory response was the bauxite schedule split and the Group A definition revision; both are discussed under the casualties section.
Group A cargoes: the principal schedules
The Group A schedule list grows at every IMSBC Code amendment cycle, but a handful of cargoes carry most of the trade volume and most of the casualty record.
Iron ore fines (IOF) are particles predominantly below 1 mm produced in the beneficiation of iron ore, shipped mainly from India, Brazil, and increasingly West Africa. Coarse iron ore in lumps and pellets is Group C; the fines fraction is what creates the Group A hazard. The dedicated Group A iron ore fines schedule requires the modified Proctor-Fagerberg test (PFD80). Iron ore concentrate, a more thoroughly beneficiated product, has its own schedule covered in the iron ore concentrate IMSBC schedule.
Nickel ore is the lateritic ore shipped mainly from Sulawesi, Halmahera, and the Philippines to Chinese smelters, rich in clay minerals (smectite, kaolinite) that give it low drainage permeability and a natural moisture that is frequently above TML during the rainy season. It’s the single most lethal liquefaction cargo in the modern casualty record by seafarer fatalities. The dedicated schedule is covered in nickel ore IMSBC schedule.
Mineral concentrates from wet beneficiation include zinc, lead, copper, iron pyrite, and silver concentrates, many of which are Group A and B together. The generic MINERAL CONCENTRATES schedule covers those without a dedicated entry; specific schedules are discussed in mineral concentrates IMSBC schedule.
Bauxite fines, reclassified to Group A after the Bulk Jupiter loss, are distinguished from the coarser bauxite grade by particle size and drainage behaviour. The Group A bauxite fines schedule and the revised Group C bauxite schedule became mandatory from 1 January 2021 under Amendment 05-19 (MSC.462(101)). The bauxite IMSBC schedule covers the split in detail.
Coal is unique in carrying Group A and Group B hazards simultaneously. Under Amendment 07-23, coal is treated as a Group A cargo where its particle size distribution is dominated by fines below 5 mm, and the modified Proctor-Fagerberg method applies to those coals. It is also Group B for self-heating and methane generation throughout. The coal IMSBC schedule covers both hazards.
Mill scale and mill scale fines from steelmaking, stored outdoors and often wet against their TML, are a lesser-traded but documented Group A cargo. Amendment 07-23 (MSC.539(107), mandatory 1 January 2025) added further Group A schedules including ground granulated blast-furnace slag powder, magnesite fines, dunite fines, crushed granodiorite fines, and baryte flotation chemical grade.
Documented casualties
The nickel ore cluster: October to December 2010
Three vessels sank in quick succession while carrying nickel ore from Indonesian ports to China. The Jian Fu Star capsized on 27 October 2010 with the loss of 13 of her 25 crew. The Nasco Diamond went down on 10 November 2010, killing 21 seafarers; post-incident reporting revealed the vessel’s master had explicitly warned before departure that the cargo was too wet and had documented his concern. The Hong Wei sank on 3 December 2010 with 10 further fatalities. Together these three losses killed 44 seafarers in 37 days. All three were attributed to nickel ore liquefaction from cargoes loaded at Indonesian ports during the wet season.
The Harita Bauxite (despite her name, she was carrying nickel ore at the time) sank on 17 February 2011 with the loss of 15 lives while loaded from Obi Island, Indonesia.
The Vinalines Queen sank on 25 December 2011 carrying approximately 54,000 tonnes of nickel ore from Indonesia’s Morowali Port to Ningde, China. Twenty-two of her 23 crew were lost; a single survivor, the cook, was found on a raft days later and described the ship developing an immediate severe list and capsizing within minutes. The vessel disappeared in water approximately 5,000 metres deep and was never found. The probable cause was nickel ore liquefaction.
In the period from October 2010 through December 2011, cargo liquefaction of nickel ore from Indonesian and Philippine origins was the probable cause of at least four total losses and 66 seafarer deaths.
Iron ore fines: 2009
The Asian Forest capsized on 17 July 2009 in the approaches to Mangalore, India, with the loss of 24 crew. The Black Rose capsized on 9 September 2009 off Paradip, India, killing the chief engineer as the crew abandoned ship. Both cargoes were iron ore fines loaded during the monsoon season from Indian ports, and investigations in both cases identified cargo liquefaction as the cause. The Indian Directorate General of Shipping established an inquiry committee and a laboratory approval framework in direct response; that work fed the modified Proctor-Fagerberg procedure for iron ore fines and the dedicated Group A iron ore fines schedule made mandatory from 1 January 2017 under Amendment 03-15 (MSC.393(95)).
Three further losses attributed to iron ore fines from Indonesian ports, the Jian Fu Star, Nasco Diamond, and Hong Wei in late 2010, reinforced the pressure for the schedule revision.
The Bulk Jupiter and bauxite reclassification
The Bulk Jupiter sank on 2 January 2015 off the coast of Vung Tau, Vietnam, while carrying 46,400 tonnes of bauxite loaded at Kuantan, Malaysia. Eighteen of her 19 crew were lost; a single survivor was rescued. The loss occurred within approximately twenty minutes of the alarm being raised.
The investigation concluded that the cargo had undergone dynamic separation. The fine fraction of the bauxite had formed a mobile slurry above the solid lower layers, creating a free surface effect that overwhelmed the vessel’s stability before the crew could respond. At the time, bauxite was classified as a Group C cargo not liable to liquefy; the Bulk Jupiter loss exposed that classification as wrong for fine-fraction bauxite with high moisture.
IMO’s response was threefold. The Global Bauxite Working Group, established through the Sub-Committee on Carriage of Containers and Cargoes (CCC), developed a modified Proctor-Fagerberg test specific to bauxite. Amendment 05-19 (MSC.462(101)), mandatory from 1 January 2021, split bauxite into a Group A bauxite fines schedule and a revised Group C coarser-fraction bauxite schedule. Amendment 06-21 (MSC.500(105)), mandatory from 1 December 2023, defined dynamic separation as a formal mechanism in the Group A definition. Each of those steps traces directly to the loss of 18 people on one January morning.
The Emerald Star: 2017
The Emerald Star capsized in the Philippine Sea on 13 October 2017 while carrying nickel ore from Indonesia, with 26 crew aboard. Fifteen were rescued by vessels in the area; eleven were lost. Survivors described the ship developing a list to port that the officers were unable to correct, consistent with cargo liquefaction. The Emerald Star loss demonstrated that the cluster of 2010-2011 nickel ore casualties had not eliminated the problem; the same cargo, the same origins, and the same mechanism produced the same outcome six years later.
Statistical summary
Intercargo’s Bulk Carrier Casualty Report 2025, covering the ten years 2015 to 2024, recorded 20 bulk carrier total losses of 10,000 dwt and above, with 89 seafarer fatalities in total. Cargo liquefaction accounted for 55 of those deaths, 61.8% of the total, making it the dominant cause of bulk-carrier fatalities over the decade despite representing a fraction of total incidents. This pattern is consistent with the mechanism: liquefaction produces rapid, total losses with few survivors, while other incident types such as groundings and structural failures produce more losses but proportionally fewer deaths.
The regulatory controls
The IMSBC Code and SOLAS Chapter VI
The IMSBC Code was adopted by IMO Resolution MSC.268(85) and made mandatory under SOLAS Chapter VI from 1 January 2011, replacing the recommendatory earlier Code of Safe Practice for Solid Bulk Cargoes. The Code is amended on a roughly two-year cycle. The current mandatory edition incorporates Amendment 07-23, adopted in Resolution MSC.539(107) on 8 June 2023 and mandatory from 1 January 2025. Amendment 06-21 (MSC.500(105)) is mandatory from 1 December 2023. Amendment 08-25 (MSC.575(110)) applies voluntarily from 1 January 2026 and becomes mandatory from 1 January 2027.
Under SOLAS Chapter VI, Regulation 2, the shipper must provide the master in writing, in good time before loading, with cargo information that includes the BCSN (Bulk Cargo Shipping Name), the IMSBC group, the TML certificate, and the moisture content certificate. For Amendment 07-23 shipments on bulk carriers of 150 metres or more, the declaration must also include the bulk density of the cargo.
The shipper’s declaration requirements
The documentation chain for a Group A cargo is:
- A cargo declaration stating the BCSN, group, chemical composition, declared moisture content (wet mass basis), and, from Amendment 07-23 onwards, bulk density.
- A TML certificate from an accredited laboratory, obtained within six months before the start of loading, using the Appendix 2 method prescribed for the cargo type.
- A moisture content certificate confirming moisture was sampled and tested within seven days before the commencement of loading and that the measured moisture is less than the TML.
- For Group A and B cargoes, additional MHB information covering chemical hazards.
None of these documents may be provided after loading begins; they must reach the master in advance. A cargo declared under an individual schedule (iron ore fines, nickel ore) must use the test method specified in that schedule. A cargo declared under the generic MINERAL CONCENTRATES entry may use any applicable Appendix 2 method, but the laboratory must confirm applicability based on the cargo’s particle size and character.
The master’s right and duty to refuse
IMSBC Code Section 4.3 preserves the master’s right to refuse or suspend loading where the documentation is absent, outdated, or shows MC equal to or above TML. In most circumstances this is not merely a right but a duty: a master who loads a Group A cargo on a certificate the master knows to be deficient cannot use the shipper’s failure as a shield if the cargo liquefies.
Section 7 of the IMSBC Code provides a limited exemption for ships specially constructed or fitted to carry Group A cargoes above their TML. Such vessels require reinforced double-bottom structure, fitted bilge systems capable of handling partially liquefied material, and stability assessments specific to the liquefied condition. No standard Handysize, Supramax, Ultramax, or Panamax bulk carrier meets these requirements without specific modification and class certification. The practical consequence: when a shipper cannot certify that MC is below TML, no ordinary commercial bulk carrier may legally carry the cargo. The cargo must wait, be blended with drier material, or be further processed.
Port state control examinations under the Paris and Tokyo Memoranda of Understanding include checks on cargo documentation. A missing or invalid Group A declaration, or evidence that a Group A cargo was loaded above its TML, is a detainable deficiency. The flag state and the classification society also sit behind these checks, the flag through the statutory force it gives the IMSBC Code and the class through the loading manual and structural limits the cargo must respect.
Loading precautions under the Code
The Code sets several mandatory precautions for Group A loading:
Hold preparation. Bilge suction systems must be tested and confirmed operational before loading. Bilge well covers must be correctly fitted. Hatch covers must seal correctly; water infiltration through a defective cover can push an otherwise-compliant cargo above its TML during the voyage.
Loading suspension in rain. Loading of a Group A cargo must stop during precipitation. Rain on an open hatch over a partially loaded fine cargo can raise the surface moisture content in minutes, creating a layer already above TML even if the bulk of the cargo was compliant.
Trimming. After each hold is filled the cargo must be trimmed so that the height difference between peaks and troughs does not exceed 5% of the vessel’s breadth. Uneven loading concentrates overburden stress in peak areas, where liquefaction is more likely to initiate, and produces an off-centre static moment. Trimming also removes the void channels between high spots that let free moisture migrate.
Bilge monitoring. Bilge levels must be monitored through the voyage. Rising bilge water carrying fine particles in a hold loaded with a Group A cargo is a sign of moisture migrating from the cargo, not merely weather-related ingress.
Voyage conduct if liquefaction is suspected
If signs of cargo liquefaction develop at sea, a developing list with no other cause, sluggish or heavy roll motion suggesting reduced metacentric height, or bilge wells filling faster than rain and condensation explain, the master’s options are limited and the time window is short.
Reduce speed and alter course to take the seas at the most comfortable angle. Reducing ship motion slows the cyclic shear loading on the cargo and may slow the progression of pore-pressure build-up, but it cannot reverse liquefaction already in progress. Avoid sharp helming and synchronous rolling, which amplify the heeling moment from any fluid mass in the holds. Maintain the maximum stability margin available: don’t slack ballast tanks unnecessarily, and don’t transfer ballast in ways that reduce GM.
Pumping bilges is not a cure. The water in the bilge wells is a symptom; the bulk of the pore water is distributed through the cargo mass and cannot be removed by the ship’s bilge system. A false confidence from pumped bilges has been noted in several casualty accounts.
The entire Group A regime is built around preventing a liquefying cargo from going aboard, not managing it once at sea. The documented time from first list to capsize in several nickel ore and bauxite casualties was under thirty minutes. A slow, gradual listing can become an irreversible, accelerating capsize once the cargo migrates past a critical point, and there’s no intervention available at sea that reliably stops that process. The only reliable defence is turning away wet cargo at the berth.
Why the hazard persists despite the rules
The Group A framework is not technically deficient. The mechanism is well understood, the test methods are standardised, the certificate requirements are clear, and the master’s right to refuse is established in law. Liquefaction casualties still occur because the commercial conditions around the worst trades press against every control point at once.
The highest-risk cargoes are high-volume, low-value bulks, nickel ore and iron ore fines, shipped from ports with variable testing infrastructure, often during tropical rainy seasons, under charter-party terms that impose demurrage on delay. A shipper who dries cargo or waits for it to dry faces real commercial loss. A shipper who submits a certificate from a laboratory whose accreditation is questionable, or who does not retest after rainfall, faces only the possibility of detection. The master who refuses loading faces a demurrage dispute and commercial pressure from the operator. The Nasco Diamond casualty showed that even a master who explicitly warned before departure that the cargo was too wet, and who documented that warning, could not prevent the vessel from loading.
Amendment 07-23’s mandatory bulk density declaration, effective 1 January 2025, addresses one gap. IMO’s casualty circulars and class society guidance bulletins after each cluster of losses address the information environment. The addition of new Group A schedules at each amendment cycle closes the gap for cargoes previously carried under a Group C or unlisted status. But the underlying commercial pressure, the gap between the cost of compliance and the cost of non-detection, is why the Intercargo statistics show liquefaction still killing more bulk-carrier seafarers than any other single cause in the decade through 2024.
Limitations
The IMSBC Code is amended on a two-year cycle, and the schedule applicable to a specific cargo, including its group classification, required test method, and carriage conditions, must be read from the edition in force for the voyage. Amendment 07-23 (MSC.539(107)) is mandatory from 1 January 2025; Amendment 08-25 (MSC.575(110)) is mandatory from 1 January 2027. A cargo that was Group C or unlisted on a past voyage may be a scheduled Group A cargo on the next.
TML values are cargo-specific. Two cargoes presented under the same BCSN from different mines and processing plants can have TML values differing by several percentage points because of differences in mineralogy, grind size, clay content, and drainage behaviour. The only valid TML for a specific shipment is the value determined by an accredited laboratory on a representative sample of that batch within the six-month validity window.
The can test is a screening check that can condemn a cargo but cannot clear it. A dry can test result does not confirm the cargo is below its TML and must not be treated as a substitute for laboratory certification.
The casualty accounts in this article draw on published investigation reports, IMO circulars, P&I club analyses, and Intercargo reporting. Where the cause was attributed to liquefaction, that reflects the official or most widely accepted finding of the responsible investigation authority. In some cases the official finding was probable rather than confirmed, particularly for vessels that sank in deep water with no wreck survey.
The regulatory requirements described here represent the general position under the IMSBC Code through mid-2026. Flag state implementation may lag IMO amendments, and the competent authority of the load port may apply additional or different requirements. Masters should verify the requirements applicable to the specific cargo, load port, and flag state for every voyage.
See also
Calculators
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