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Home › Dangerous Goods & Chemical Cargo › CTU Code: Packing and Stowage of Cargo Transport Units
Operational guide · Operational procedure

CTU Code: Packing and Stowage of Cargo Transport Units

The packer checks and documents internal packing; terminal, carrier and ship perform external acceptance inspection of a sealed CTU without claiming to have checked its interior.

CTU Codecontainerpackingdangerous goods

Operational Explanation

The CTU Code allocates duties by function. The packer/filler checks internal suitability, distribution, securing, segregation, closure, marks/placards and seal. Terminal/carrier/ship check accessible documents and external condition at acceptance; a sealed CTU is not autonomously opened.

Regulatory Reference

The CTU Code (2014, developed by IMO/ILO/UNECE) is not mandatory in itself but is referenced as a good-practice reference by the IMDG Code for the packing of transport units; MSC.1/Circ.1498 provides complementary informative material.

Scope of Application

Packer/filler: internal packing. Terminal, carrier and ship at acceptance: documents, VGM where applicable, UN number/proper shipping name, marks/labels/placards, seal, external condition, leakage, odour, heat, deformation and other visible evidence.

Procedure / How to Complete It

  1. Packer: check CTU interior, distribution, securing, segregation and closure under CTU/IMDG Code.
  2. Packer: apply marks/placards and seal and produce correct documents.
  3. Acceptance: reconcile documents, VGM, UN/PSN, marks/placards and seal.
  4. Perform external acceptance inspection for damage, leakage, odour, heat and deformation.
  5. On inconsistency or hazard evidence place on hold/reject and activate Company/terminal and competent authority; do not open without reason, authority and procedure.

Practical Example

A sealed CTU has a missing placard and abnormal odour: the ship does not claim to have checked internal segregation and does not open it; it places the unit on hold and activates the competent procedure.

What Typically Goes Wrong

Numerous analyses of incidents on board container ships (including fire episodes linked to dangerous goods) have identified poor packing and securing inside the CTU, rather than misclassification alone, as a contributing factor: a correctly classified package that is poorly secured inside the container can still shift, be damaged and generate a leak or an ignition source during the voyage.

Common Mistakes Mistake Library

MistakeConsequenceHow to avoid it
CTU filled without a prior check of the structural integrity of the unitRisk of loss of tightness or structural failure during transportAlways inspect the CTU before filling it, even when supplied by a third party
Liquid dangerous goods stowed above solid goods in the same unitRisk of contamination or damage in the event of a leakAlways apply the liquids-below-solids stowage rule set out in the CTU Code
External placarding of the CTU not updated after changes to the contentsMisleading information for terminal personnel and emergency respondersCheck the consistency between external placarding and actual contents before final closure

What the PSCO Checks

Port State Control Officers (PSCOs) may check on a sample basis the integrity of CTUs containing dangerous goods, the consistency of external placarding with the transport documentation, and any visible signs of damage or cargo instability.

Operational Tips

Preparation checklist

FAQ

Can the ship confirm internal segregation in a sealed CTU?
No. It can check documents and external condition; internal packing belongs to the packer unless authorised opening follows an appropriate procedure.
Does visual inspection prove compliant packing?
No. It is an external acceptance inspection and cannot see the interior.
When may a CTU be opened?
Only with a reason, authority, risk assessment and appropriate procedure.

Related Topics

Dangerous Goods Manifest and Notification to Port AuthoritiesCargo Securing Manual and Cargo Lashing

Last substantive revision of this page: 31 August 2026 · page fingerprint 45bbf54c7a9e