In July 2021, at the 76th session of the Marine Environment Protection Committee (MEPC 76), the IMO adopted an amendment to the International Convention on the Control of Harmful Anti-fouling Systems on Ships (AFS Convention).

 

In addition to the already prohibited organotin compounds which act as biocides (try butyl tin, TBT) in anti-fouling systems, the ingredient cybutryne (CAS No. 28159-98-0) will be prohibited as per the amendments to the AFS Conven­tion entering into force on 1 January 2023.

 

The affected ship types and effective dates are listed in the table below:

 

Anti-fouling system	Control measures	Application	Effective date
Cybutryne CAS No. 28159-98-0	Ships shall not apply or re- apply anti-fouling systems containing this substance.	All ships	1 January 2023
Cybutryne CAS No. 28159-98-0	Ships bearing an anti-fouling system that contains this substance in the external coating layer of their hulls or external parts or surfaces on 1 January 2023 shall either: (1)         remove the anti-fouling system; or (2)         apply a coating that forms a barrier to this sub- stance leaching from the underlying non-compliant anti-fouling system.	All ships except: (1)                              fixed and floating plat- forms, FSUs and FPSOs that have been constructed prior to 1 January 2023 and that have not been in dry-dock on or after 1 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).	At the next scheduled renewal of the anti-fouling system after 1 January 2023, but no later than 60 months following the last application to the ship of an anti- fouling system containing cybutryne.

 

 

Surveys and certification requirements for AFS

 

• All ships should remove or seal such anti-fouling systems at the next scheduled renewal of the anti-fouling system after 1 January 2023, but no later than 60 months following the last application of such anti-fouling system prior to 1 January 2023.

 

• The section of the model form of the IAFS Certificate listing the compliance options for controlled anti-fouling systems on the ship have been modified to include extra cybutryne tick boxes.

 

• Owners/operators should be aware of vessels and fleet survey and docking schedules for anti-fouling purchases.  These should be accompanied by cybutryne-free statements from the manufacturers to obtain an AFS certificate from the attending surveyor.