MARPOL Annex III: Harmful Substances Carried in Packaged Form
Package and CTU marking follows specific IMDG provisions, including the 5 L/5 kg package exception; spill reporting follows MARPOL Article 8/Protocol I and is coordinated with SMS and safety reporting.
Operational Explanation
Determine from the Dangerous Goods List and special provisions whether a substance is a marine pollutant. Package marking and CTU placarding/marking have distinct rules. An IMDG exception may apply to packages of liquids ≤5 L or solids ≤5 kg net mass where general packaging provisions are met; do not automatically extend it to the CTU.
Regulatory Reference
MARPOL Annex III and IMDG Code for harmful substances in packaged form. Incident reporting: MARPOL Article 8 and Protocol I, A.851(20) guidelines as amended, and current national operational contact points.
Scope of Application
Packages, CTUs and bulk containers with marine pollutants under DGL and applicable provisions. The 5 L/5 kg exception is limited to packages within its conditions; CTU marking is checked separately.
Procedure / How to Complete It
- Determine marine-pollutant status from DGL and special provisions.
- Apply package mark and CTU placarding/marking under their respective rules.
- Assess the ≤5 L liquid or ≤5 kg net solid package exception only where general packaging provisions are met.
- On spill activate emergency response/SMS and protect people and ship.
- Assess reportability under MARPOL Article 8/Protocol I and coastal/port duties; report without delay to applicable recipients/contact points.
- Coordinate safety, dangerous-goods and pollution reporting without duplication or omitted recipients.
Practical Example
Small inner packages may meet the 5 L/5 kg exception if all conditions are satisfied; that does not automatically decide CTU marking. On release, the ship uses a coordinated SMS flow and national contact points, not a presumed separate Annex III notice in every case.
What Typically Goes Wrong
Always marking every package without checking the exception, extending a package exception to the CTU or creating two separate reports solely because material is Annex III.
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| 'MARINE POLLUTANT' marking not applied because it is considered redundant relative to the primary IMDG class labelling | Non-compliance with MARPOL Annex III even when the IMDG safety classification is correct | Always apply the specific marine pollutant marking when required, in addition to, not instead of, the primary class labelling |
| Transport documentation showing only the primary IMDG hazard classification, omitting marine pollutant status | Documentation incomplete for the purposes of MARPOL Annex III | Check and explicitly include marine pollutant status in the documentation, when applicable |
| Notification procedures in the event of a spillage at sea limited to safety emergency management alone, without the specific notifications required by MARPOL Annex III | Failure to comply with specific environmental notification obligations in the event of a spillage | Integrate the specific notification procedures for the spillage of substances classified as marine pollutants into the contingency plan |
What the PSCO Checks
Operational Tips
- Do not treat marine pollutant classification as a secondary detail relative to the primary IMDG hazard class: it requires its own marking and documentation.
- Always check the marine pollutant status of every substance carried, regardless of its primary hazard class, since the two classifications follow different logics.
- Integrate notification procedures for the spillage of marine pollutants into the contingency plan, distinct from the safety emergency response alone.
Preparation checklist
- Marine-pollutant status checked
- Package mark and CTU marking separated
- 5 L/5 kg exception used only within scope
- Emergency/SMS response ready
- MARPOL Article 8/Protocol I assessed
- Current contact points and coordinated reporting
FAQ
Related Topics
Last substantive revision of this page: 31 August 2026 · page fingerprint ad52565f6f09