Why coal cargoes continue to drive disproportionate risk

Coal remains one of the most widely traded solid bulk commodities worldwide. Despite its long history in maritime transport, it continues to generate a disproportionate number of incidents, claims and near misses. Fires, explosions, self-heating and liquefaction events still occur with regularity.

For vessel owners, operators, terminals and their insurers, coal represents a convergence of safety risk, operational disruption and claims exposure. The entry into force of the 2023 edition of the International Maritime Solid Bulk Cargoes (IMSBC) Code on 1 January 2025, followed by the adoption of Amendment 08 25, reinforces a long-standing message: coal should not be regarded as a routine cargo.

Why Coal Still Matters

Operationally, coal occupies a unique position. It may behave as a conventional dry bulk cargo, yet under certain conditions it presents hazards more commonly associated with dangerous goods. The IMSBC Code reflects this duality: coal may present both Group B (chemical) and Group A (liquefaction) hazards unless testing demonstrates otherwise.

For blended cargoes, a conservative assessment is required. Where liquefaction hazards cannot be excluded through testing and classification, the cargo should be treated as presenting both liquefaction and chemical hazards.

Coal’s physical characteristics, including particle size distribution, moisture content, bulk density and angle of repose, directly influence its behaviour during transport. Depending on its composition and loading condition, coal may emit methane, self-heat, generate flammable atmospheres, deplete oxygen, corrode ship structures, or liquefy when moisture exceeds the Transportable Moisture Limit. Each hazard carries distinct operational and commercial implications.

Regulation Catching Up With Operational Reality

The mandatory application of the IMSBC Code 2023 edition on 1 January 2025 reinforced the regulatory framework governing the carriage of solid bulk cargoes. It maintained established requirements relating to moisture management, gas monitoring, cargo declarations, hold preparation and cargo trimming, while incorporating amendments developed through ongoing operational experience and the continued review of bulk cargo risks.

Since 2019, coal has generally been treated as a cargo falling within both Group A and Group B unless competent testing demonstrates otherwise. This has increased the importance of accurate, timely and credible cargo information being provided to the Master.

Amendment 08 25 continues the trend towards greater specificity within cargo schedules and carriage requirements. While reducing ambiguity in certain areas, it also reinforces the need for owners, operators and terminals to scrutinise cargo documentation and investigate inconsistencies between declared cargo characteristics and observed condition. Early adoption of these provisions can strengthen both safety outcomes and claims defensibility.

The Persistent Risk Landscape

Despite regulatory developments, coal’s principal risk drivers remain unchanged:

• Liquefaction: Fine coal loaded near or above the Transportable Moisture Limit may shift during the voyage, reducing stability and, in extreme cases, leading to capsize.
• Methane emission: Methane accumulation in cargo holds can create flammable or explosive atmospheres, requiring continuous monitoring and controlled ventilation.
• Self-heating and spontaneous combustion: Rising carbon monoxide levels provide early indication of developing self-heating, requiring careful monitoring and controlled response.
• Corrosion: Certain coal types react with moisture to form acidic by products, requiring clean, dry bilges and systematic monitoring.
• Toxicity and asphyxiation: Oxygen depletion and hazardous gases necessitate strict monitoring and safe access procedures.

Effective risk control depends on disciplined execution across the entire cargo chain, from testing and declaration through to loading and voyage monitoring.

Operational Discipline as a Risk Control

Reviews of coal related incidents and claims consistently point to recurring failure patterns: moisture exposure during loading, late or generic cargo declarations, inadequate trimming and limited crew familiarity with coal specific requirements.

These are rarely isolated events. More often, they reflect systemic gaps in how cargo risk is identified, validated and monitored across the supply chain.

Across claims, the same drivers continue to emerge, including preventable exposure to rain, incomplete or delayed documentation and missed early warning indicators. These gaps not only increase operational risk but can significantly weaken a company’s position when a claim arises.

While the quality of shipper-provided information remains critical, shipboard oversight is decisive. Routine but timely checks, including moisture observations and atmosphere monitoring, provide early indication where cargo behaviour deviates from declared characteristics.

Where anomalies are identified, prompt escalation and thorough documentation are essential, both to manage the risk effectively and to ensure decisions can be defended if required.

From Compliance to Competence

Compliance alone is no longer sufficient. The organisations that perform most consistently in coal carriage are those that combine regulatory adherence with a practical understanding of cargo behaviour.

In many cases, incidents are not caused by a lack of rules but by a gap between compliance and understanding. When crews and operators understand how coal behaves in practice, they are better equipped to question cargo declarations, recognise early warning signs and act decisively.

In this context, the difference between a managed risk and a costly claim is rarely procedural. It lies in the ability to identify when cargo behaviour does not align with what has been declared and to act on that insight early.

Conclusion

Coal remains one of shipping’s most complex bulk cargoes. As regulatory scrutiny and claims analysis become increasingly data driven, treating coal as a routine cargo exposes stakeholders to risks that are well understood and increasingly difficult to defend.

Vigilance, competence and informed judgement are essential.

In this environment, independent technical insight plays an increasingly important role. Supporting owners, operators, terminals and insurers with cargo assessment, operational guidance and incident investigation strengthens decision making before, during and after loading, helping to reduce risk exposure and manage claims with greater confidence.

Written by: Panagiotis Kasionis, Maritime Consultant at BMT