Operational Guide · Registers & Logbooks

# Cargo Record Book (Record Book for Noxious Liquid Substances)

The mandatory record book for tankers carrying noxious liquid substances in bulk: how to complete it, and why the Category X prewash is the point most closely scrutinised during inspection.

MARPOL Annex II Cargo Record Book NLS chemical tanker

## Operational Explanation

The Cargo Record Book documents every operation involving noxious liquid substances (NLS) carried in bulk: loading, internal transfers, discharge, tank cleaning and the discharge of residues, whether ashore or, where permitted, at sea within the limits set for the substance's category.

NLS substances are classified into four categories (X, Y, Z, OS) according to their level of risk to the marine environment: Category X carries the strictest constraints, including mandatory prewash before departure from the discharge port.

## Regulatory Reference

MARPOL Annex II (Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk): governs the classification of substances (Categories X, Y, Z, OS), the discharge limits for residues, the prewash requirement for Category X, and the content of the Cargo Record Book, to be completed according to the approved format and kept on board.

## Scope of Application

Every tanker certified to carry noxious liquid substances in bulk (chemical tanker), under the International Pollution Prevention Certificate for the Carriage of Noxious Liquid Substances in Bulk (NLS Certificate).

## Procedure / How to Complete It

1. Verify the category (X, Y, Z, OS) of every NLS substance loaded, according to the NLS Certificate and the applicable IBC Code lists.
2. For Category X residues: carry out the mandatory prewash before departure from the discharge port, according to the ship's Procedures and Arrangements (P&A) Manual.
3. Record every operation (loading, internal transfer, discharge, washing, discharge of residues) in the Cargo Record Book, with quantity, date, time and position.
4. Have every entry signed by the officer responsible for the operation, and every page by the Master.
5. Keep the Cargo Record Book on board for the required period, available for PSC inspection.

### Diagram: mandatory prewash for Category X residues (MARPOL Annex II)

## Practical Example

Example entry: "Category X prewash carried out in accordance with the P&A Manual, tank no. 3, residues discharged ashore down to an analysed concentration ≤0.1% by weight, as confirmed by the terminal surveyor. Tank washings discharged ashore until completely empty."

## Real Cases

PSC inspections on chemical tankers frequently focus on cross-checking the Cargo Record Book, the P&A Manual approved for the specific ship, and the shore discharge documentation: inconsistencies between these documents, especially for Category X residues, are among the most serious environmental deficiencies found on this type of ship.

## Common Mistakes Mistake Library

Mistake | Consequence | How to avoid it
--- | --- | ---
Category X prewash not carried out, or not compliant with the ship's specific P&A Manual | Serious violation of MARPOL Annex II, a high-severity environmental deficiency | Follow exactly the procedure in the P&A Manual approved for the ship, not a generic procedure
Cargo Record Book not signed by the responsible officer or by the Master | PSC deficiency for an invalid record | Systematically verify the required signatures on every entry and page
No verification of residue concentration before considering the Category X discharge complete | Discharge stopped prematurely, breach of the 0.1% threshold | Always wait for the surveyor's analytical confirmation before considering the prewash complete

## PSC Observations

PSCOs on chemical tankers check the consistency between the Cargo Record Book, the P&A Manual and the shore discharge documentation, paying particular attention to operations involving Category X substances.

## Operational Tips

- Always follow the ship's specific P&A Manual for the prewash, not a generic procedure applied to other ships.
- Do not consider a Category X discharge complete without the surveyor's analytical confirmation of the residue concentration.
- Systematically verify that every entry and page of the Cargo Record Book is signed as required.

## Checklist

- NLS category of every substance verified against the NLS Certificate/IBC Code
- Category X prewash carried out according to the ship's specific P&A Manual
- Residue concentration verified analytically before concluding the discharge
- Every entry in the Cargo Record Book signed by the responsible officer
- Every page signed by the Master

## FAQ

What are the NLS substance categories under MARPOL Annex II?
Category X (highest risk, discharge at sea prohibited except after prewash and shore discharge of residues), Category Y, Category Z (decreasing risk, with more permissive discharge limits) and OS (Other Substances, not classified as harmful).
Is prewash always mandatory for Category X?
Yes, except for specific exemptions provided for certain Category X products when the tank will be reloaded with the same product or a compatible one, according to the provisions of the approved P&A Manual.
Does the Cargo Record Book replace the Oil Record Book on a chemical tanker?
No: they are separate records. The Oil Record Book covers operations with hydrocarbons (MARPOL Annex I, e.g. fuel and oily residues), while the Cargo Record Book specifically covers operations with noxious liquid substances (MARPOL Annex II). A chemical tanker may require both.
🎬 Additional photos, videos and interactive diagrams for this topic will be available in a future version of the platform.

## Related Topics

Tank Cleaning Loading/Discharging Plan IBC Code and Operations on Chemical Tankers

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