NL 277/22 | MCI - International Convention on the Control of Harmful Anti-Fouling Systems on Ships, 2001 – Prohibition of Cybutryne in Anti-Fouling Coating Systems (Circular 270/2022)

Oct 19, 2022

Refers to: Ship Owners / Managers / Operators of CI flagged vessels, PHRS Surveyors / Representatives     

Action Date: 1st Jan 2023


On the 1st January 2023 amendments to the Anti-Fouling Systems (AFS) Convention, adopted through Resolution MEPC.331(76) will enter into force. The amendments introduce new requirements that ban the future installation of anti-fouling systems which contain a toxic substance called cybutryne (CAS No. 28159-98-0).

Ships shall not apply or re-apply anti-fouling systems containing cybutryne on or after 1st January 2023.

Ships bearing an anti-fouling system that contains cybutryne in the external coating layer of their hulls or external parts or surfaces on the 1st January 2023 shall either:

1. Remove the anti-fouling system; or

2. Apply a coating that forms a barrier to this substance leaching from the underlying non-compliant anti-fouling system.

The measures listed above must be put in place at the next scheduled renewal of the antifouling system after 1st January 2023, but no later than 60 months following the last application to the ship of an anti-fouling system containing cybutryne.

Existing coatings on the following ships are excepted from the requirements:

1. Fixed and floating platforms, Floating Storage Units, and Floating Production Storage and Offloading installations that have been constructed prior to 1st January 2023 and that have not been in dry-dock on or after 1st January 2023;

2. Ships not engaged in international voyages; and

3. Ships of less than 400 gross tonnage engaged in international voyages, if accepted by the coastal State(s).


Actions for ship owners and managers

Owners and managers of vessels with anti-fouling systems containing cybutryne are urged to get in touch with Maritime Cook Islands at, in order to arrange for an AFS survey and the issuance of a new revised AFS certificate.

The Circular 270/2022 can be found here.


Do not hesitate to contact us for more information you may need on the above.


October 19th, 2022 - PHRS Head Office