Redefining Risk: The IMDG Amendment 42-24 for Carbon & Charcoal Ocean Transport

This essay examines why the change matters, what it entails, and how proactive risk analysis can prevent future disasters, a message all stakeholders shall heed.

In 2025-2026, the global maritime supply chain faces one of its most consequential regulatory shifts in a generation — the mandatory enforcement of Amendment 42-24 of the International Maritime Dangerous Goods (IMDG) Code, specifically affecting the classification and carriage of carbon and charcoal (UN 1361/1362). This change, precipitated by cargo fires, container losses, and near-miss incidents in recent years, demands a paradigm shift in how the industry understands and manages self-heating substances at sea.

A Wake-Up Call: Real-World Safety Failures

Globally, carriers and port authorities have recorded an increasing number of self-heating incidents involving charcoal and carbon cargoes. These materials — ubiquitous in industrial processes, filtration media, and consumer products — can undergo spontaneous ignition if improperly packed or thermally unstable.

In 2023 alone, multiple incidents were reported in major transshipment hubs where containers loaded with apparent “low-risk” charcoal spontaneously combusted during storage or transit. Though none resulted in loss of life, they caused:

• Container fires

• Quarantined terminal operations

• Costly emergency responses

• Ship schedule disruptions

Investigations revealed inadequate weathering, poor temperature control, and lack of DG classification as common root causes. In several cases, consignments exempted from dangerous goods documentation based on outdated provisions were later found to exceed safe self-heating thresholds.

These events were not isolated anomalies, they highlighted systemic risk in assuming charcoal/carbon cargoes are benign without rigorous scientific and regulatory compliance.

IMDG 42-24: Turning Science into Safety

Risk Analysis: From Compliance to Operational Assurance

A Strategic Imperative for Industry Leaders

---

IMDG 42-24: Turning Science into Safety

To address these risks, the latest IMDG Code amendment introduces two critical safety pillars for carbon and charcoal shipments:

1. Mandatory Dangerous Goods Classification (UN 1361/1362):

   Charcoal and other carbon materials can no longer be treated as non-DG based solely on selective test results. They must be declared as Class 4.2 self-heating substances unless stringent criteria are met and documented.

   
   

2. Enhanced Pre-Shipment Controls (SP 978/SP 979):

   Weathering for ≥14 days after production, or packing under inert gas with ≥24 hours storage

   Mandatory temperature check (≤40 °C) at the point of packing

   UN-approved packaging and container headspace requirements

   Detailed Dangerous Goods Declaration (DGD) including production/packing dates and packing temperature.

Mandatory Dangerous Goods Classification

(UN 1361/1362)

Charcoal and other carbon materials can no longer be treated as non-DG based solely on selective test results. They must be declared as Class 4.2 self-heating substances unless stringent criteria are met and documented.

Enhanced Pre-Shipment Controls

(SP 978/SP 979)

• Weathering for ≥14 days after production, or packing under inert gas with ≥24 hours storage

• Mandatory temperature check (≤40 °C) at the point of packing

• UN-approved packaging and container headspace requirements

• Detailed Dangerous Goods Declaration (DGD) including production/packing dates and packing temperature

These measures are rooted in decades of materials science and thermal hazard analysis, acknowledging that charcoal/carbon’s porosity and reactive surface area can catalyze internal heat generation unless controlled

Risk Analysis: From Compliance to Operational Assurance

Regulatory compliance alone is not risk management. Companies must adopt evidence-based safety evaluations at every stage — from factory kilns to container terminals.

Source Control: Understanding Material Behavior

Carbonaceous materials are thermodynamically dynamic. Weathering reduces volatile components, but only empirical monitoring (e.g., thermocouple loggers) can prove thermal stability. This data must be integrated into:

• Supplier quality protocols

• Pre-shipment inspection checklists

• Automated temperature logging systems

Failing to manage source risk is not just a regulatory breach — it’s a latent hazard.

Process Control: Data-Driven Packing Decisions

Temperature compliance checkpoints should be:

• Documented with calibrated instruments

• Linked with production batch data

• Cross-verified by independent auditors

Packing decisions must not be based on visual inspection alone. Scientific data is the new currency of safe ocean transport.

Carrier & Terminal Integration

Lines are already refusing bookings or requiring pre-audited shipper credentials. Terminals demand advanced documentation before acceptance. A scientific approach to risk analysis — with documented temperature profiles and weathering logs — will differentiate compliant shippers from those facing delays and financial penalties.

A Strategic Imperative for Industry Leaders

The IMDG 42-24 changes are not bureaucratic red tape — they are evidence-based safeguards grounded in materials science and incident data. Embracing them proactively yields:

• Enhanced safety for crews and terminals

• Reduced risk of container fires

• Faster carrier acceptance and fewer operational holds

• Competitive advantage in compliance maturity

Industry leaders must view these requirements not as a burden, but as an opportunity to elevate safety culture and operational excellence.