CARRIAGE OF MILITARY CARGO BY SEA: REGULATORY COMPLIANCE, SAFETY, AND BEST PRACTICES

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Published: 9 October 2025

Updated: 27 October 2025

INTRODUCTION

The transportation of military cargo by sea is an operation that requires meticulous planning and a robust understanding of regulatory frameworks, safety standards and security protocols. In an era of geopolitical tensions and increased demand for defence logistics, moving military goods – ranging from small arms ammunition and riot control agents to armoured vehicles and explosive ordnance – presents challenges far beyond those of ordinary commercial shipments. At the core of this process lies the International Maritime Dangerous Goods (IMDG) Code, developed by the International Maritime Organization (IMO). Though often treated as a compliance checklist, the IMDG Code is, in practice, a living document that sets the standard for maritime safety and risk management when dealing with hazardous cargoes, including military consignments. 

SANCTIONS, EXPORT CONTROLS AND DUE DILIGENCE

In addition to operational hazards, shipping military cargo involves navigating a complex web of international sanctions and export controls. Many defence-related items are subject to restrictions under UN Security Council¹ Resolutions, European Union regulations², or the laws of individual states such as the United States’ Office of Foreign Assets Control³ (OFAC). Operators are obliged to screen shippers, consignees and any intermediaries against relevant sanctions lists. Failing to do so can result in severe consequences, including seizure of the cargo, suspension of trading licenses, and the loss of protection and indemnity (P&I) insurance coverage. This article does not cover the necessary screening and sanction checks required, and it is therefore prudent to seek legal advice from counsel experienced in sanctions compliance before proceeding.

CLASSIFICATION OF MILITARY CARGO

One of the first and most critical steps in shipping military cargo is correct classification under the IMDG Code⁴. This is not merely an administrative formality. A proper UN number and Class/Division determine the packing instructions, vessel stowage and segregation, documentation, and the safety measures required on board⁵. For example, Class 1 covers explosives, subdivided into Divisions 1.1 through 1.6 to reflect different hazard levels⁶. Division 1.1 (mass‑explosion hazard) includes items such as UN 0006, Cartridges for weapons, with bursting charge (1.1E), which attract the strictest handling and stowage controls⁷. At the other end, UN 0012, Cartridges, small arms, typically Division 1.4S, presents only a minor explosive hazard with effects largely confined to the package⁸. Even “low‑risk” military goods must still be handled carefully. Misclassification or inadequate precautions can have serious consequences for ship and crew.

PACKAGING AND CONTAINER SELECTION

Packaging and container selection are equally vital. Military cargo is almost always transported in UN‑certified packaging, designed to contain the specific risks associated with each hazard class⁹. Munitions are typically packed in steel boxes lined with foam or other shock‑absorbing materials to minimise the chance of accidental detonation. These packages are then palletised for ease of loading and to maintain stability during transit. Containers used must display valid CSC plates confirming structural soundness and compliance with international standards¹⁰. High‑value or sensitive shipments should be secured with tamper‑evident seals¹¹, and many operators now fit tracking devices to containers carrying strategic materials¹². Regular inspections of these containers are critical: best practice calls for the crew to log inspections in the vessel’s records, supplemented by photographs to document container condition and seal integrity¹³.

DOCUMENTATION AND APPROVALS

Accurate documentation sits at the heart of compliance. Every consignment of military cargo must be accompanied by a Dangerous Goods Declaration that includes the UN number, proper shipping name, hazard class, packaging group and the net explosive quantity (NEQ) where applicable. But dangerous goods paperwork is only part of the story. Military shipments often require supporting authorisations, including export and import licenses, end-user certificates and approvals from relevant port or flag state authorities. Misdeclaration, whether deliberate or due to oversight, remains one of the greatest risks in this field. It can lead to cargo rejection, vessel detention, substantial fines, or even criminal liability for the parties involved. Given the stakes, many operators implement a secondary verification process to cross-check all documents before loading.

VESSEL SUITABILITY AND STOWAGE PLANNING

Beyond paperwork, vessel suitability is a fundamental concern. Not every ship is permitted or equipped to carry military explosives. A vessel’s Document of Compliance for Dangerous Goods specifies precisely which classes of cargo may be carried and under what conditions¹⁴. For instance, many vessels require Class 1.1 cargo to be stowed on deck due to the potential blast hazard, whereas Class 1.4 cargo may be stowed underdeck if segregation requirements and fire safety measures are in place. Stowage planning must also account for proximity to heat sources and crew accommodation spaces. Closed cargo units containing explosives are often required to be placed at least 2.4 m from heated fuel oil tanks, steam pipes, or other ignition hazards¹⁵. Lashing and securing arrangements, as detailed in the ship’s Cargo Securing Manual (CSM), must be followed rigorously. Heavy project cargo, such as , demands additional care, as their weight, high centre of gravity, and potentially non-standard shapes, can impact the vessel’s and may require special securing methods. Point loading, or concentrated weight in specific areas, must be accounted for to prevent structural damage. Before loading, the condition of the deck or hold should be thoroughly documented to ensure that any pre-existing damage is noted and to avoid responsibility for damage caused during the voyage. Crews must understand the impact on metacentric height (GM) and be prepared to adjust ballast or revise stowage plans to maintain safe trim and stability throughout the voyage¹⁶.

SECURITY AND THEFT PREVENTION

Security is a concern that extends well beyond the threat of accidental incidents. Military cargo is a target for theft, sabotage and smuggling. Criminal syndicates and politically motivated actors may attempt to access or divert such shipments, particularly at transshipment ports or during lengthy layovers. Operators are increasingly adopting layered security measures. Tamper-evident seals and high-security padlocks are now standard, as is real-time tracking to monitor container movements. In regions such as the Gulf of Guinea or the Horn of Africa, where piracy and armed robbery remain threats, shipowners frequently coordinate escorts with port authorities or deploy private maritime security teams (PMSTs). When using private security personnel, clear rules of engagement and strict adherence to flag state regulations are critical to avoid legal and insurance complications¹⁷. In addition to physical security measures, it is essential that crew members maintain discretion regarding the transport of sensitive military cargo. Discussions about the specifics of the shipment, including its contents, routes, or destinations, should be avoided in public forums, with external parties, or on social media. Taking pictures or sharing details for private use must be prohibited to safeguard against potential threats or leaks.

EMERGENCY PREPAREDNESS AND FIRE SAFETY

Emergency preparedness must be approached as a core component of any military cargo shipment. The crew must have access to Safety Data Sheets (SDS) for all hazardous materials on board, detailing the correct firefighting methods and first-aid measures¹⁸. The IMDG Emergency Schedules (EmS) guide remains the definitive reference for response procedures, outlining specific steps to manage fires, leaks, or explosions. For example, in the case of a fire involving chemical, smoke (CS) rifle grenades, the crew should be prepared to evacuate the area and take necessary precautions. If the situation allows, sheltering in the accommodation spaces is acceptable, if the ship’s fire suppression and detection systems are working properly. The ship’s fire suppression and detection systems must be fully operational and tested before departure and drills should be conducted so all personnel understand their roles in an emergency¹⁹. Personal protective equipment appropriate to the cargo, such as fire-resistant suits, breathing apparatus and chemical-resistant gloves, should be readily accessible and maintained in good condition. It is also important that smoking regulations are strictly followed, with designated smoking areas well away from the cargo holds and any hazardous materials to reduce the risk of fire.

INTERMEDIATE PORTS AND DUAL-USE CONSIGNMENTS

Military cargo voyages often involve intermediate port calls, and operators must verify that these ports permit the transit or temporary storage of such consignments. For example, under the US ‘Military Cargo Preference Act’, 100% of military cargo must be carried on US-flag vessels unless a waiver is granted, even when shipments move between foreign ports²⁰. This means routing through an intermediate port that cannot accommodate this requirement may trigger compliance or waiver issues.

Similarly, consignments classified as dual-use goods, i.e civilian items with potential military application, require additional scrutiny. Exporters and carriers should ensure appropriate dual-use export licenses are obtained and accepted by intermediate ports and customs authorities²¹. Failure to do so may result in rejection, detention, or sanctions exposure.

Port capability is also a consideration. Some major European and Asian terminals are developing dual-use logistics frameworks, including heavy-lift capacity, breakbulk areas, and civil–military interoperability agreements, to support such consignments²². Operators are advised to check whether intermediate ports are equipped and legally authorised to handle dual-use or sensitive cargo prior to planning the voyage.

CYBERSECURITY CONSIDERATIONS

A newer, but no less pressing, challenge is cybersecurity. As shipping operations have become digitised, attackers have found ways to exploit vulnerabilities in electronic documentation systems, container tracking platforms and even navigational software. There have already been cases where cybercriminals tampered with cargo manifests or disabled shipboard IT systems. When transporting military cargo, the stakes are especially high because a successful breach can reveal sensitive information or enable theft. Shipowners and operators should adopt comprehensive cybersecurity practices, including network segmentation, strict access controls, up-to-date software patches, and continuous monitoring for anomalies. The IMO’s guidelines on maritime cybersecurity (MSC-FAL.1/Circ.3²³) provide a useful framework to develop company policies and crew training programs. 

CONCLUSION

Ultimately, the safe carriage of military goods by sea is an exercise in integrated risk management. Compliance with the IMDG Code is only the starting point. Operators must also engage in meticulous planning, foster close cooperation with port authorities and flag states and instil a culture of diligence and accountability among all parties involved. From pre-shipment classification and packaging to mid-voyage monitoring and emergency preparedness, each stage demands attention to detail. Even minor oversights can have far-reaching consequences, not only for the safety of the crew and vessel but also for legal liability and international reputation.

In today’s environment, where supply chains are under scrutiny and geopolitical risks are rising, diligence is not optional. It is a professional obligation and a critical safeguard for all stakeholders. The successful movement of military cargo is rarely achieved by simply following checklists. Instead, it requires operators to anticipate problems rather than react to them, to verify rather than assume and to prepare rather than hope. When these principles guide practice, the carriage of military goods can be executed safely, efficiently and in full compliance with the law.

¹ United Nations – Sanctions (https://www.un.org/securitycouncil/sanctions/information)

² European Commission – EU trade relationships by country/region (https://policy.trade.ec.europa.eu/eu-trade-relationships-cou
try-and-region_en)

³ Office of Foreign Assets Control (https://ofac.treasury.gov/)

⁴ International Maritime Dangerous Goods (IMDG) Code, Vol. 1, Part 2 – “Classification”.

⁵ IMDG Code, Vol. 1, Part 7 – “Provisions concerning transport operations” (stowage, segregation, handling)

⁶ UN Recommendations on the Transport of Dangerous Goods – Model Regulations, Ch. 2.1.1 (definition of Class 1 divisions).

⁷ IMDG Code, Vol. 2, Dangerous Goods List, UN 0006 – “Cartridges for weapons, with bursting charge”, Class 1.1E.

⁸ IMDG Code, Vol. 2, Dangerous Goods List, UN 0012 – “Cartridges, small arms”, Class 1.4S.

⁹ IMDG Code, Vol. 1, Part 4 – Packing and tank provisions.

¹⁰ International Convention for Safe Containers (CSC) 1972, as amended – CSC plates confirm inspection and structural fitness

¹¹ ISO 17712:2013 – Freight container mechanical seals.

¹² U.S. Department of Defence, Defence Transportation Regulation, Part II, Cargo Movement, §203 – notes use of GPS tracking for sensitive shipments.

¹³ IMDG Code, Vol. 1, Part 7.5 – Surveys and inspections.

¹⁴ SOLAS Chapter II-2, Regulation 19 – Carriage of dangerous goods.

¹⁵ IMDG Code, Vol. 1, Part 7.2.7 – Separation from heat sources.

¹⁶ IMO Code of Safe Practice for Cargo Stowage and Securing (CSS Code), Ch. 2 – Ship stability.

[17] IMO MSC.1/Circ.1405/Rev.3 – Interim guidance to shipowners on the use of PCASP (Privately Contracted Armed Security Personnel) on board ships.

¹⁸ IMDG Code, Vol. 1, Part 5.4.3 – Requirement for Safety Data Sheets for dangerous goods on board.

¹⁹ SOLAS Chapter III, Reg. 19 – Emergency training and drills

²⁰ US Department of Transportation – Maritime Administration – Frequently Asked Questions (FAQs) – Cargo Preference (https://www.maritime.dot.gov/ports/cargo-preference/frequently-asked-questions-faqs-cargo-preference)

²¹ Bureau of Industry and Security – Dual Use Export Licenses (https://www.bis.doc.gov/index.php/all-articles/2-uncategorized/91-dual-use-export-licenses)

²² Xpert Digital – Dua-use heavy-load container terminals – For the EU internal market and Europe’s military defense security (https://xpert.digital/en/dual-use-heavy-duty-container-terminals)

²³ International Maritime Organization – Guidelines on Maritime Cyber Risk Management (https://wwwcdn.imo.org/localresources/en/OurWork/Security/Documents/MSC-FAL.1-Circ.3-Rev.3.pdf)

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